1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

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Expression profiling of genes associated with nitrogen use efficiency in rice varieties under organic and conventional management
(Department of Molecular Biology and Biotechnology, College of Agriculture, Vellayani, 2024-05-02) Elizabeth Jose; KAU; Soni, K B
The study entitled “Expression profiling of genes associated with nitrogen use efficiency in rice varieties under organic and conventional management” was conducted in the Department of Molecular Biology and Biotechnology during 2019-2023. The objectives of the study were to identify differentially expressed genes associated with nitrogen use efficiency (NUE) in rice varieties under organic and conventional management and to find out the polymorphism in the gene sequences. A pot culture experiment was conducted in a completely randomized design with five replications. Four rice varieties namely Jaiva, Ezhome 2, Uma and Jyothi were compared under two nutrient management practices (KAU PoP, Adhoc Organic PoP of KAU) along with an absolute control. Under organic management, nutrients were applied on N equivalent basis. The observations on morphological, physiological, biochemical and yield parameters and expression of genes associated with NUE were taken at seedling, panicle initiation and grain filling stages. All rice varieties showed significantly taller plants, greater number of tillers per hill, higher grain and straw yields per hill with KAU PoP. Jaiva and Ezhome 2 showed a significantly greater number of productive tillers per hill (P=0.001 and P=0.02) under KAU PoP, and Ezhome 2 produced higher filled grains per panicle under organic PoP. Jyothi showed significantly higher root depth and root biomass per hill (46.34 cm, 18.6 g) under organic PoP. At the vegetative stage, all varieties except Jaiva and Uma, exhibited significantly higher photosynthetic rates under KAU PoP. The varieties Ezhome 2 and Uma showed higher leaf protein content under organic PoP. All rice varieties, except Ezhome 2, showed significantly higher amino acid content under KAU PoP. The nutrient management practices did not significantly affect the reducing sugar content in Jyothi, compared to other varieties which showed higher values under KAU PoP. All the varieties showed higher NUE with KAU PoP than organic PoP. Maximum NUE was seen in Jyothi (0.28 kg yield increase/g N applied) under KAU PoP. Variation in NUE under both nutrient management was found to be lesser in the variety Jaiva (23.8%). 195 Expression profiles of NUE-associated genes such as OsNRT1.1a, OsNRT1.1b, OsAMT1.1, OsAMT1.2, OsAMT1.3, OsNRT2.1, OsNAR2.1, OsGS1.1, OsNADH-GOGAT1 were analyzed at different stages of growth by performing RT-qPCR using SYBR Green dye and β-actin as the reference gene. At the three-week seedling stage, ammonium uptake and transporter genes OsAMT1.1, OsAMT1.2, and nitrate uptake and transporter gene OsNRT2.1 which are root-specific in nature, exhibited significantly higher expression under organic PoP in Jaiva and Jyothi. Jyothi also showed a significantly high expression of glutamine synthase gene, OsGS1.1 in the leaf and root tissues (0.72 and 8.28 folds respectively). OsNADH-GOGAT1, a gene associated with nitrogen assimilation exhibited significantly higher expression in the root tissues of all rice varieties, except Jaiva under organic PoP. At the panicle initiation stage, Uma and Jyothi showed comparatively higher expression of OsNRT1.1a, OsNRT1.1b, OsAMT1.1, OsAMT1.2, OSAMT1.3, OsNRT2.1, OsNAR2.1 and OsNADH-GOGAT1 under organic PoP. At the grain-filling stage, Uma showed significantly higher expression of OsAMT1.1 (3.19 folds), OsAMT1.2 (5.24 folds), OsAMT1.3 (7.65 folds), OsNAR2.1 (11.02 folds), OsNADH-GOGAT1 (2.2 folds) in root tissues under organic PoP. Jyothi, under organic management, showed significantly higher expression of the OsNRT2.1 gene (6.95 folds) in root tissues. In Jaiva, nitrogen assimilatory genes like OsGS1.1 and OsNADH-GOGAT1 showed higher expression in leaf and root tissues under PoP and for Jyothi, they were found elevated (P<0.005) under organic PoP. The full-length sequencing of differently expressed OsAMT1.1 of Jaiva yielded a sequence comprising 2671 bp. This is the initial comprehensive gene sequencing report for the OsAMT1.1 gene of an organic rice variety. It showed a similarity (99.7%) to that of NERICA L19 (O. sativa × O. glaberrima). Uma exhibited an insertion of 41 bp in the promoter region compared to the other three varieties. Furthermore, some single nucleotide polymorphisms were also identified in the promoter region of Jaiva, Ezhome, Uma and Jyothi. In conclusion, the present study explored the response of the key genes involved in the uptake, transport and assimilation of nitrate and ammonium under different nutrient management strategies in determining nitrogen use efficiency in rice varieties. 196 Jaiva and Jyothi exhibited superior efficiency in both nitrate and ammonium uptake, correlating with higher NUE and narrower yield gaps between organic and fertilizer-based management. In the initial stages of crop growth, an elevated expression of OsAMT1.1 and OsAMT1.2 was seen in Jaiva and Jyothi under organic management, whereas OsAMT1.3, which has a N-derepressible role was highly expressed in Uma under organic management. The variety, Uma was found to be less nitrogen-efficient and was highly influenced by ammoniacal fertilizer. Even though OsAMT1.1 and OsAMT1.2 were less expressed in the initial stages of Uma, a significant increase was observed in its later stages. OsNRT2.1 and its partner protein OsNAR2.1, which are important in regulating nitrate transport and signaling, were upregulated in Jaiva and Jyothi under organic PoP, influencing root development and contributing to superior agronomic use efficiency. The higher expression of OsGS1.1 in the seedling and grain filling stages of Jyothi under organic PoP contributed to grain development and filling, demonstrating better NUE and a reduced yield gap. Ezhome 2, by exhibiting higher OsGS1.1 expression at the seedling stage, displayed increased filled grains, emphasizing the significance of early gene expression in yield determination. Furthermore, OsNADH-GOGAT1's role in ammonia assimilation, productive tiller formation, and grain development was evident, with varieties like Ezhome 2 showcasing its positive impact on grain number and tiller productivity under organic PoP. The findings highlight the complexity of nitrogen response and metabolism in rice and emphasize the importance of nutrient management strategies in achieving optimal NUE and crop yield. The observed variations in the gene expression across different varieties and growth stages provide a foundation for further research and potential molecular interventions to enhance NUE in rice.
Assessment, mapping and modelling of soil carbon pools and stock in selected agro-ecological units of south Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture ,Vellayani, 2024-04-22) Bincy, B; KAU
A study entitled “Assessment, mapping and modelling of soil carbon pools and stock in selected agro-ecological units of south Kerala” was carried out to examine the impact of various agricultural land use systems on soil carbon fractions, pools and stock, soil aggregation, glomalin and polysaccharide contents, and to generate soil carbon maps using GIS and predict soil carbon changes in the future climate change scenario using modelling technique. The agro-ecological units (AEUs) of south Kerala namely, southern coastal plain (AEU 1), Onattukara sandy plain (AEU 3), southern laterites (AEU 8), south central laterites (AEU 9) and southern and central foothills (AEU 12) were selected for the study. In each AEU, different agricultural land use categories as described by IPCC for the carbon inventory such as, garden land (coconut), wet land (rice), fallow land (uncultivated) and plantation (rubber) were also selected. Soil profiles upto a depth of one meter was taken from the selected sites and samples were collected from various depth intervals of 0 to 25, 25 to 50, 50 to 75 and 75 to 100 cm. The surface soil samples (0 – 25 cm) were analyzed for soil properties such as pH, EC, CEC, texture, soil carbon fractions (organic, inorganic, water soluble, permanganate oxidizable, microbial biomass carbon and mineralizable carbon) and organic matter fractions (humic acid, fulvic acid and humin). The depth wise distribution of soil carbon pools (active, passive and slow carbon pools), bulk density and total organic carbon (TOC) were analyzed. Soil organic carbon stock, density, carbon indices (CPI, CLI, CMI, LQI, GWP) and carbon proportion/ turnover were computed. Soil aggregation was evaluated by analyzing water stable aggregates, mean weight diameter, macro-micro aggregate size distribution, aggregate associated organic carbon, glomalin and total polysaccharides in soil. GIS based thematic maps of soil organic carbon, stock, density and land quality were generated in ArcGIS 10.5.1 software. The soil organic carbon changes in the future climate change scenario were predicted using DNDC (Denitrification Decomposition) model. The results revealed that soil texture was loamy sand to sandy clay loam in AEU 1, sandy loam to sandy clay loam in AEU 3 and 9, sandy loam to sandy clay in AEU 8 and sandy clay loam to sandy clay in AEU 12. The sand fraction (45.32-80.34 %) was found to be more than silt (9.60 – 21.14%) and clay (8.87-39.15 %). The pH and EC of soils ranged 254 from 4.77 to 5.73 and 0.06 to 0.44 dS m⁻1 respectively. The CEC of soil varied between 2.60 and 6.69 c mol(p+) kg-1 with the highest value in rubber land use and the lowest in uncultivated land. Soil organic carbon (SOC) ranged from 0.34 to 0.73, 0.44 to 0.99, 0.40 to 1.09, 0.25 to 0.97 and 0.26 to 1.26 per cent in AEU 1, 3, 8, 9 and 12 respectively. Among the land uses, rubber land use recorded the highest SOC (1.03 %) followed by coconut (0.75 %) and rice (0.60 %) and the lowest SOC was observed in uncultivated land (0.34 %). The water soluble, permanganate oxidizable and the particulate organic carbon varied from 34.01 to 162.81 mg kg-1, 1.21 to 7.37 mg g-1 and 0.37 to 2.75 per cent respectively. The different AEUs and land uses followed the order AEU 12 > AEU 9 >AEU 8 > AEU 3>AEU 1 and rubber > coconut > rice >uncultivated land respectively. Similar trend was observed for microbial biomass carbon which ranged from 121.2 to 424.4 mg kg-1 with the highest value in AEU 12 and rubber land use. Percentage contribution of water soluble, particulate and permanganate oxidizable C to TOC was 0.31 to 0.43, 40.12 to 69.72 and 12.62 to 19.73 per cent respectively. The organic matter fractions viz. humic acid, fulvic acid and humin varied from 0.57 to 2.06, 0.73 to 2.33, 0.62 to 1.59 per cent respectively in different AEUs. The rubber land use showed significantly higher humic acid (1.72 %), fulvic acid (2.01 %) and humin (1.44 %) than coconut, rice and uncultivated land. Percentage contribution of humic acid, fulvic acid and humin to total organic matter ranged from 29.40 to 32.51, 32.30 to 36.42 and 26 to 29.25 per cent respectively. The active, slow and passive pools of carbon in soil ranged between 0.09 and 1.03, 0.17 and 0.78, 0.13 and 1.26 per cent respectively with the highest value in AEU 12 and the lowest in AEU 1. In different land uses it followed the order rubber >coconut> rice> uncultivated land. The soil carbon pool showed a gradual decline from 0 - 25 cm to 75 - 100 cm depth with a decrease of 0.82 to 0.14, 0.63 to 0.18 and 0.97 to 0.24 per cent for active, slow and passive carbon pools respectively. The passive pool of carbon (31.95 – 38.08 %) contributed more towards total organic carbon than active (23.64-37.66 %) and slow (22.73-32.12 %) pools. 255 With depth (0-25 cm to 75-100 cm) bulk density of soil increased from 1.38 to 1.66, 1.33 to 1.68, 1.35 to 1.64, 1.33 to 1.60 and 1.29 to 1.55 Mg m-3 in AEU 1, 3, 8, 9 and 12 respectively. Higher bulk density was observed in uncultivated land than rice, coconut and rubber land uses. The TOC in soil ranged from 0.72 to 2.80, 0.69 to 2.89, 0.79 to 3.46, 0.88 to 3.18 and 0.75 to 3.56 per cent in AEU 1, 3, 8, 9 and 12 respectively. In all the AEUs the highest TOC was registered from rubber land use followed by coconut, rice and the lowest from uncultivated land. The TOC content decreased with depth (0 - 25 cm to 75 - 100 cm) and the values were 1.99 to 0.95, 2.24 to 0.92, 2.45 to 1.05, 2.53 to 1.05 and 2.38 to 1.01 per cent for AEU 1, 3, 8, 9 and 12 respectively. Total soil organic carbon stock varied from 162.71 to 293.22, 175.80 to 275.79, 188.63 to 322.36, 199.73 to 331.48, 144.54 to 355.63 Mg ha-1 in AEU 1, 3, 8, 9 and 12 respectively with the highest stock in AEU 12. Among the land uses it followed the order rubber>coconut>rice>uncultivated land. SOC stock decreased from 0 to 25 cm to 75 to 100 cm depths and the values were 76.28 to 36.59, 79.97 to 35.88, 86.70 to 39.61, 88.10 to 39.48 and 79.90 to 35.80 Mg C ha-1 for AEU 1,3, 8, 9 and 12 respectively. The soil organic carbon density of the surface (0-25 cm) soil varied from 3.07 to 6.01, 3.68 to 5.76, 3.84 to 7.81, 4.19 to 7.19 and 3.27 to 6.96 kg m-2 in AEU 1, 3, 8, 9 and 12 respectively with the highest density observed for AEU 12. With respect to different land uses it followed the order rubber (6.96 kg m⁻2 )> coconut (5.86 kg m⁻2) > rice (5.10 kg m⁻2) > uncultivated land (3.61 kg m⁻2). The carbon indices such as lability, pool and management index ranged from 0.30 to 0.93, 0.19 to 0.51 and 5.55 to 38.42 respectively in different AEUs and were found to be the highest in AEU 12 and rubber land use. The land quality index based on SOC stock in kg m-2 was rated as medium (6 - 9 kg m-2 ) in all AEUs. The mineralizable C content in soil varied from 1.40 to 3.45, 1.18 to 3.41, 1.04 to 3.04, 1.23 to 3.35 and 1.01 to 3.02 mg g⁻¹ in AEU 1, 3, 8, 9 and 12 respectively. The highest value was observed from AEU 1 and rice land use. Similar trend was obtained for global warming potential of soils based on CO2 evolution which varied from 31.82 to 78.41, 26.89 to 79.02, 22.89 to 69.02, 28.03 to 76.06 and 22.96 to 68.64 in AEU 1, 3, 8, 9 and 12 respectively. The C proportion and turnover rates were in the range of 0.25 to 0.77 256 and 0.04 to 0.17 respectively. The C proportion was the highest in AEU 12 and rubber land use whereas the C turnover was the highest in AEU 1 and rice land use. With respect to aggregate distribution, the larger size fractions (5-8, 2-5, 1-2 & 0.5-1 mm) were found to be higher in rubber land use and the smaller size fractions (0.25-0.5 & 0.1-0.25 mm) were higher in rice land use. The macro aggregate fraction (> 250 μm) ranged from 22.60 to 75.70 per cent with the highest value in rubber land use while the micro aggregate fraction (53 – 250 μm) ranged from 10.78 to 56.46 per cent with the highest value in rice land use. The water stable aggregates and mean weight diameter were ranged from 22.60 to 34.31 per cent and 0.56 to 2.90 mm respectively and were the highest in rubber land use. The aggregate associated organic carbon was the highest in the size fraction of 1 to 2 and 0.5 to 1 mm (1.03-1.27 g kg-1) compared to other fractions. The organic carbon associated with macro (> 250 μm) and micro (53-250 μm) aggregates are in the range of 2.16 to 5.70 and 0.30 to 0.95 g kg-1 respectively with the highest value in rubber land use. The glomalin related soil protein ranged from 1.22 to 6.35 mg g-1 and polysaccharides from 2.12 to 9.24 mg g-1 . Irrespective of the AEUs the highest glomalin and polysaccharides were observed in rubber land use. The DNDC model predicted organic carbon changes in coconut land use systems in Thuravoor (AEU 1), Bharanikkavu (AEU 3), Ookkod (AEU 8), Karavaram (AEU 9) and Vellarada (AEU 12) under RCP 4.5 and RCP 8.5 future climate change scenario. The DNDC model predicted an increase in soil organic carbon status from 2020 to 2050 under RCP 4.5 and RCP 8.5 scenario but the rate of increase in soil carbon were more pronounced under 4.5 scenario where relatively lower CO2 emission was observed. The predicted SOC for 2050 under RCP 4.5 scenario were 1.26, 1.04, 1.44, 1.23 and 1.27 for Thuravoor (AEU 1), Bharanikkavu (AEU 3), Ookkod (AEU 8), Karavaram (AEU 9) and Vellarada (AEU 12) respectively. The organic carbon fractions, pools and stock were the highest in agro-ecological unit 12. Among the land uses, rubber contributed more to the SOC stock and pools indicating the prevalence of conducive environment for the buildup of carbon. The macro 257 and micro aggregates, aggregate associated carbon, glomalin, polysaccharides and C proportion were also higher in rubber land use indicating it as a potential carbon sink. Among the carbon fractions particulate organic carbon contributed more to total organic carbon. Among the carbon pools passive pool contributed more towards the total organic carbon. The carbon associated with larger fractions (1-2 mm and 0.5-1 mm) and macro aggregates (> 250 μm) were high in rubber land use indicating physical protection and sequestration in soil. The DNDC model predicted an increase in the SOC status from 2020 to 2050 under RCP 4.5 and RCP 8.5 scenario of future climate change.
Physiological and molecular assessment of abiotic stress tolerance in selectively fertilized coconut hybrids (Cocos nucifera L.)
(Department of Plant Physiology, College of Agriculture,Vellayani, 2024-03-14) Afna Mol, O P; KAU; Roy Stephen; Gladis, R
The present study entitled “Physiological and molecular assessment of abiotic stress tolerance in selectively fertilized coconut hybrids (Cocos nucifera L.) was carried out in the Department of Plant Physiology, College of Agriculture, Vellayani during 2018-2023. The objective of the study was physiological and molecular evaluation of selectively fertilized coconut hybrids for water stress and temperature stress tolerance and to assess genetic variability for temperature stress tolerance through pollen selection at critical temperature. The study consisted of four experiments. In the first experiment, 10 year old field grown coconut palms of the following varieties Kerasree (WCT X MYD)- 198 selectively fertilized, Keraganga (WCT X GB)-selectively fertilized, Kerasree (WCT X MYD) Hybrid, Keraganga (WCT X GB) Hybrid and West Coast Tall at Regional Agricultural Research Station, Pilicode, Kasaragod were used as the experimental material for the study. The experiment was carried out in Randomized Block Design (RBD) with four replications during 2019 March to 2019 April. Water stress was imposed by withdrawing irrigation from the field for one month and physiological and biochemical observations were made at 15 days interval .Then the palms were irrigated on 30th day and recovery responses were analysed on 15th day after the irrigation rescheduling. On physiological analysis, selectively fertilized Kerasree showed higher relative water content and epicuticular wax of the leaves. Keraganga selectively fertilized showed maximum photosynthetic rate and cell membrane stability index. Leaf temperature was minimum in Kerasree selectively fertilized hybrids followed by Keraganga selectively fertilized hybrid. WCT recorded higher transpiration rate followed by Kerasree selectively fertilized hybrid. Stomatal conductance was higher in WCT and then in Kerasree selectively fertilized hybrids. In all the parameters tested both the selectively fertilized hybrids responded positively towards drought than their normal hybrids and this was an indication of higher water use efficiency in them. Recovery response after rewatering was also higher in selectively fertilized hybrids than their normal hybrids. The biochemical parameters like chlorophyll content, antioxidant enzymes viz SOD and peroxidase activities were found maximum in Kerasree selectively fertilized hybrids under water stress condition. Recovery response of these parameters were also found elevated in Kerasree selectively fertilized hybrids. Also Kerasree selectively fertilized hybrids showed lowest membrane damage (lipid peroxidation value) compared with normal hybrids and WCT. Amount of proline in leaves was found higher in WCT, which was on par with Kerasree selectively fertilized hybrid and Keraganga selectively fertilized hybrid. 199 In the second experiment, molecular characterization was carried out in the above five treatments. Protein profiling of leaves was done in all the five treatments of experiment one, using SDS-PAGE, in which, there was variation in the intensity of large subunit (55 kDa) as well as small subunit (around16 kDa) of RuBisCO, among the treatments. The intensity of those bands were found higher in WCT and Kerasree selectively fertilized hybrid .The band expressed in selectively fertilized hybrid in between 26 kDa to 36 kDa was absent in other treatments.. SSR markers CncirE2, CncirE10, CncirE12 and CncirH4 were screened in five treatments and polymorphism was observed in CncirE2, CncirE12, and CncirE10. RNA-seq tranascriptomic analysis of Kerasree selectively fertilized hybrid in reference with Kerasree was done to identify the key differentially expressed genes (DEGs) responding to water stress tolerance in Kerasree selectively fertilized hybrid. A total of 16671 genes were found expressed in Kerasree SF differing from Kerasree. 9635 genes were upregulated and remaining 7036 genes were down regulated in Kerasree SF.Abiotic stress related genes like late embryogenesis abundant protein Lea5 and HSPs were found differently expressed in Kerasree S.F hybrid in response to water stress. Gene ontology of the identified genes revealed that in terms of biological processes the following were the most represented GO terms (GO:0006749, 24 proteins, GO:0006468, 23 proteins,GO:0009415,12). In cellular component (GO: 0016020, 31 proteins) and in molecular function (GO: 0005524, 56 proteins, GO: 0009408, 21 proteins) the above shown were the most represented GO terms. In experiment three, physiological assessment of temperature stress tolerance of selectively fertilized coconut hybrids was done. Pollen grains were collected from the selectively fertilized coconut palms during summer season. The pollen grains were incubated in specific pollen germination media and exposed to different temperature ranging from 35oC to 45oC for a period of 2 hours. The temperature at which only 20-30 % of pollen germinated was identified as the critical temperature stress for pollen germination. From the results obtained, both the selectively fertilized hybrid of Kerasree and Keraganga were noted with maximum critical temperature for pollen germination (42oC) followed by WCT (40oC).This indicated 200 the temperature stress tolerance of selectively fertilized hybrids over their normal hybrids. Pollen viability was found maximum in WCT followed by Kerasree selectively fertilized hybrid. Accumulation of starch was found significantly higher in Kerasree selectively fertilized hybrid and the protein in WCT. The fourth experiment was conducted to screen temperature stress tolerance of 30 coconut genotypes in Regional Agricultural Research Station, Pilicode for recognizing the temperature stress tolerance through critical temperature for pollen germination. Significant genetic variation in critical temperature was discerned among the treatments. Andaman ordinary and Tanjore coconut genotypes were observed with higher critical temperature (42oC) for pollen germination. Hence they can be used as a pollen parent in hybridization programs for developing temperature stress tolerance. The present study revealed that Kerasree selectively fertilized and Keraganga selectively fertilized hybrids of coconut were more tolerant to water stress than normal hybrids in terms physiological, biochemical and molecular parameters. Selectively fertilized hybrids developed through pollen selection at critical water potential also have temperature stress tolerance. By selective fertilization techniques it may be possible to add water stress and temperature stress tolerance traits to high yielding coconut hybrids.
Molecular diagnosis and management of Papaya ringspot virus causing papaya ringspot diseases
(Department of Plant Pathology, College of Agriculture,Vellayani, 2024-04-17) Josiya Joy; KAU; Radhika, N S
The research work entitled “Molecular diagnosis and management of Papaya ringspot virus causing papaya ringspot disease” was undertaken in the Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram, during 2019-24, with the objectives; molecular diagnosis and recombinant coat protein production of Papaya ringspot virus (PRSV), and evaluation of the efficacy of beneficial microorganisms and botanical inthe management of papaya ringspot disease (PRSD). Roving survey was carried out across five Agro-ecological units (AEUs) of Kerala. The disease incidence (DI) ranged from 50.25 per cent (Kayyur-Cheemeni) to 100 per cent (Kalliyoor, Venganoor, Balaramapuram, Pallichal, Kayamkulam, Mavelikkara, Velukkara, Irinjalakuda and Shoranur). Vulnerability index (VI) of the plants to PRSV in the surveyed locations ranged from 33.54 (Badiyadkka) to 98.22 (Kalliyoor). Serological and molecular detection confirmed the presence of PRSV in all the 20 symptomatic samples collected during survey. Phylogenetic tree constructed with the deduced amino acid sequences of CP gene of 11 Kerala PRSV isolates, revealed that Thiruvananthapuram isolates clustered together, indicating their relatedness during evolution. Mechanical inoculation on two months old Red Lady papaya seedlings under insect proof conditions was carried out to identify the most virulent PRSV isolate collected from different AEUs. At three months after inoculation (MAI), Kalliyoor isolate exhibited highest VI (96.63) followed by Alur (95.48) and Venganoor (95.22) isolates. The lowest VI was observed in Kayyur-Cheemeni isolate with 57.95 VI, followed by Cherpulassery (60.58). The recombinant coat protein of PRSV was induced in pLATE 31 expression vector with C terminal histidine tag, within BL21(DE3)pLysS expression host. PRSV recombinant coat protein was purified using Ni-NTA column chromatography. A single band was observed at 35 kDa in SDS-PAGE analysis and western blotting with PRSV antiserum, confirmed the presence of purified recombinant coat protein in the soluble fraction. Pot culture experiment was conducted to evaluate the management of PRSD using Piriformospora indica. The initial colonization of P. indica inside the papaya roots was observed five days after germination of the seeds grown in P. indica massmultiplied medium. Prophylactic colonization of P. indica exhibited lowest VI (23.10) and 68.27 per cent reduction in VI over control diseased plants at five months after PRSV inoculation (MAI). Double antibody sandwich - Enzyme linked immunosorbent assay (DAS-ELISA) at 5 MAI revealed lowest absorbance (0.23) indicating lowest virus titre in P. indica pre-colonized plants upon PRSV inoculation, compared to control diseased plants (1.23). The accumulation of reactive oxygen species (ROS) i.e., H2O2 and superoxides in the leaves were analyzed using DAB (diaminobenzidine) and NBT (nitro blue tetrazolium chloride) staining respectively. P. indica-colonized plants upon PRSV inoculation indicated a higher initial accumulation of ROS at three weeks after inoculation (3 WAI) and further reduction at 6, 9 and 12 WAI of PRSV, compared to control diseased plants. P. indica-colonized plants also exhibited enhanced antioxidant defence enzyme activity viz., catalase, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, glutamate synthase and superoxide dismutase compared to control diseased plants. Amongst PRSV inoculated treatments, P. indica pre-colonized plants exhibited highest number of leaves (20.86), leaf area (365.14 cm2), plant height (108.29 cm), stem girth (7.26 cm), shoot biomass (423.43 g), root biomass (133.96 g) and chlorophyll content (2.84 mg g-1 of fw) at five months after transplanting (5 MAT). Effect of P. indica, Bougainvillea spectabilis leaf extract (10 %) and Pseudomonas fluorescens (2 %) were evaluated against natural incidence of PRSD under field conditions at Instructional farm, College of Agriculture, Vellayani and Coconut Research Station, Balaramapuram, Thiruvananthapuram. P. indica-colonized plants exhibited lowest VI (37.63), with highest reduction in VI over control (53.85 %) followed by B. spectabilis treated plants (37.49 %) and P. fluorescens treated plants (33.31 %) at 12 months after planting (12 MAP). In DAS-ELISA, lowest virus titre with absorbance of 0.438 was observed in P. indica-colonized plants at 12 MAP, compared to the highest virus titre in control plants (1.267). B. spectabilis treated plants (0.596) also exhibited reduction in virus titre followed by P. fluorescens treated plants (0.625) at 12 MAP. P. indica-colonized plants exhibited enhancement in growth parameters viz., number of leaves (24.00), leaf area (1127 cm2), stem girth (42.74 cm) and plant height (207.39 cm) at 12 MAP. P. indica-colonized plants also enhanced the yield by 44.68 per cent followed by B. spectabilis treated plants (24.13 %) and P. fluorescens treated plants (17.99 %). Moreover, fruits from P. indica-colonized plants expressed significantly superior quality parameters. Thus, findings from the present study could aid in the preliminary detection and management of the virus, thus mitigating the widespread infection caused by PRSV. The recombinant PRSV coat protein produced in this study could be used for the development of PRSV antiserum. Additionally, our research highlights the efficacy of eco-friendly management strategies for papaya ringspot disease, with P. indica-colonization @ 106 cfu g-1 and also with four foliar sprayings as well as soil drenching of B. spectabilis leaf extract (10 %) applied at fortnightly intervals, starting from one month after planting. More field trials are to be conducted to integrate this strategy in integrated disease management (IDM) package for the effective and sustainable management of PRSD in papaya.
Piriformospora indica and its water diffusible exudates for the management of chilli anthracnose incited by colletotrichum capsici (Syd.) butler and bisby
(Department of Plant Pathology, College of Agriculture, Vellayani, 2024-07-05) Elizabeth, T Jojy; KAU
The research work entitled “Piriformospora indica and its water diffusible exudates for the management of chilli anthracnose incited by Colletotrichum capsici (Syd.) Butler and Bisby” was carried out in the Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram during 2017- 2023. The study was undertaken with the objective to evaluate P. indica- and its water diffusible exudates- primed chilli seedlings and plants against foliar infection of C. capsici; and study the biochemical and molecular mechanisms involved in this tripartite interaction. A survey conducted in the five agroclimatic zones (ACZs) of Kerala showed that the highest disease incidence (DI) and Percent Disease Index (PDI) were recorded at RARS, Pilicode (DI-90 & PDI-52.60) of northern zone, while the lowest DI was observed at farmer’s field, Kottarakkara (20%) and ORARS, Kayamkulam recorded the lowest PDI (23.63). Chilli anthracnose symptoms namely leaf spot, leaf blight, die-back, fruit rot and mummified fruits were observed in different survey locations of the five agroclimatic zones (ACZ) of Kerala. Nine C. capsici isolates and one isolate of C. gloeosporioides were obtained from the surveyed locations. All the C. capsici isolates produced sparse mycelial growth with concentric zonations of acervuli on potato dextrose agar (PDA) medium. The upper side of culture plates appeared in different shades of white and off-white to grey with regular or irregular margins, while the reverse side looked yellowish brown to black. Isolate Cc4 produced maximum mycelial growth diameter of 8.6 cm compared to 7.2 cm (minimum) in Cc2 on 7th day after inoculation (DAI). Further, microscopic characters such as mycelial width, size of conidia, acervuli, appressoria, number and length of setae were significantly different in the C. capsici isolates. The most virulent isolate of C. capsici was screened based on the lesion size produced on the artificially inoculated leaves and fruits of chilli var. Vellayani Athulya. On 7th DAI, Cc3 isolate of C. capsici produced maximum lesion size of 2.52 cm while isolate Cc4 produced minimum lesions (0.74 cm) on 292 inoculated chilli leaves. Similarly, tender, mature and ripe fruits of var. Vellayani Athulya inoculated with Cc3 isolate produced the highest lesion size (2.48, 2.34 and 2.56 cm respectively) and isolate Cc4 recorded the lowest lesions (1.62, 1.16 and 1.38 cm respectively) on 7th DAI. Thus, isolate Cc3 from Thrissur, was selected as the most virulent isolate of C. capsici. Ten selected KAU/ICAR released varieties of chilli were screened with Cc3 isolate by detached leaf and fruit inoculation method to identify the most susceptible variety. Leaves of Vellayani Athulya recorded the highest lesion size of 2.80 cm on 5 DAI compared to 1.66 cm (lowest) in Manjari. Maximum lesion size of 2.96 cm was observed on the tender fruits of Vellayani Athulya and minimum was recorded on Vellayani Thejus (1.52 cm). Lesions of 3.50 cm (highest) were observed on mature Vellayani Athulya fruits as against 2.00 cm on Manjari fruits. Similarly, ripe fruits of Vellayani Athulya recorded maximum lesion size of 3.46 cm and minimum in Vellayani Samrudhi (1.30 cm) at 7 DAI. Also, in the in vivo study, higher lesion size (3.00 cm) was observed in Vellayani Athulya fruits and lowest (1.62 cm) in fruits of Vellayani Samrudhi at 7th DAI. Standardization of P. indica-colonization in chilli var. Vellayani Athulya was done on plant nutrient medium (PNM) and chilli roots were sampled at different intervals viz., 3rd, 5th, 7th, 10th, and 15th days after colonization (DAC). Young, double-walled chlamydospores were observed within the root cells at 5 DAC. P. indica colonization gradually increased and reached a maximum of 100 per cent at 15 DAC. Dual culture of P. indica and C. capsici showed the appearance of inhibition zone (8.33 DAI) and antibiosis (12.67 DAI) at the point of interaction of the two fungi. Further microscopic observations revealed thickening and lysis of pathogen mycelium by P. indica. The growth of C. capsici was suppressed (3.85 cm) in dual culture compared to normal (6.28 cm) in control at 7th DAI. 57.22 per cent mycelial growth inhibition due to P. indica was observed at 15 DAI. Antagonistic property of P. indica-water diffusible exudates (Pi-WDE) against C. capsici was studied by in vitro poison food technique. Significant 293 differences were observed in the colour and nature of C. capsici growth on PDA media, added with different day-old Pi-WDE in comparison with control. Among them, ten day-old Pi-WDE recorded the highest inhibition (67.30 %) of pathogen mycelial growth whereas the lowest in one day-old Pi-WDE (9.29 %). Mass multiplication of P. indica in the portray medium was carried out. Rapid growth of the endophyte was recorded in a combination of farmyard manure (FYM) and coir pith (1:1), added with 2 per cent gram flour. P. indica completely covered the inoculated trays within 7 DAI. This medium was used to colonize chilli plants with P. indica for further experiments and thus, four treatments viz., P. indica alone (T1), C. capsici alone (T2), P. indica-primed seedlings + C. capsici (T3) and control (T4) were systematized for the in vitro and in vivo evaluation experiments. In vitro study of P. indica-primed chilli seedlings against C. capsici significantly reduced anthracnose lesion size and disease severity to 1.30 cm and 30.63 per cent respectively compared to 2.06 cm and 77.00 per cent in C. capsici alone at 7 DAI. Maximum root and shoot weight were recorded in the P. indicacolonized plants, irrespective of the pathogen. Pot culture experiment was also carried out in the chilli var. Vellayani Athulya. The development of anthracnose symptoms on leaves was delayed by 4 days in P. indica-colonized chilli plants as against 2 days in control. The lesion size and disease severity due to anthracnose was lower in P. indica-colonized chilli leaves (1.58 cm & 54.90 %) compared to C. capsici alone (2.86 cm & 85.20 %) at 10 DAI. Similarly, minimum lesion size and disease severity of 1.17 cm and 27.92 per cent was observed in fruits from pathogen inoculated P. indicacolonized chilli plants than in C. capsici alone (3.56 cm & 91.67 %) at 10 DAI. Field studies were conducted in rabi and summer seasons with two treatments viz., P. indica-colonized and non-colonized plants. P. indica-colonized chilli plants recorded lower anthracnose severity of 27.00 per cent in Rabi and 15.50 per cent in summer compared to 56.50 and 47.00 per cent respectively in control. P. indica colonization improved the biometric characters such as plant height, number of leaves, leaf area, number of secondary and tertiary roots, shoot 294 weight, root weight in primed chilli plants. In addition, yield of chilli was enhanced in endophyte-colonized plants compared to control. Biochemical studies on the mechanism of disease management in P. indica-colonized chilli plants at 0, 12, 24 and 72 hours after inoculation (HAI) showed increased activity of phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (PO). In contrast, the activities of 4-coumaryl CoA ligase (4-CL) and polyphenol oxidase (PPO) were enhanced in chilli plants inoculated with C. capsici alone. Isoenzyme analysis revealed higher induction of isoenzymes of PO and PPO in the P. indica-colonized plants compared to control. Enhanced induction of pathogenesis related (PR) proteins was noticed in the P. indica-colonized plants inoculated with the pathogen at 72 HAI. The capsaicin content was drastically reduced in C. capsici inoculated chilli fruits. However, fruits from P. indica-colonized plants had high capsaicin content (>30% over control) irrespective of infection. Molecular studies of the defense related genes revealed the positive role of P. indica in the management of anthracnose disease in chilli. P. indica reduced anthracnose symptoms in colonized chilli plants by the upregulation of genes involved in phenyl propanoid pathway (PAL1, 4-CL, CAD and CHS), jasmonic acid signaling pathway (PDF1.2 and AOS) and salicylic acid signaling pathway (PR1, EDS1 and PAL3); and downregulating the LOX gene involved in jasmonic acid signaling. In summary, P. indica and its WDE inhibited C. capsici under in vitro conditions. Anthracnose incidence and severity were considerably reduced in the treated chilli seedlings and plants compared to control. In addition, P. indica enhanced growth as well as yield in colonized chilli plants, thereby enhancing the fruit quality. Further, the endophyte improved disease resistance in chilli plants by increasing the defense-related enzyme activities and expression of defense genes. Thus, the root fungal endophyte, P. indica can be considered as an efficient biocontrol agent in the management of chilli anthracnose.
Technology assessment and refinement in coastal homegardens of Kerala: linkages with biodiversity and household livelihoods
(Department of Agricultural Extension Education, College of Agriculture , Vellayani, 2024-01-15) Roshni Thampi; KAU; Allan Thomas; Joy, M
The study entitled “Technology assessment and refinement in coastal homegardens of Kerala: Linkages with biodiversity and household livelihood” conducted from 2019 to 2023 focused on the primary objectives to assess crop diversity, identify the dominance of crops, delineate technology needs, sorter dimensions of technologies and analyze the adoption and technology gaps through action research for sustainable coastal home garden systems. The study also examined the social anthropogenic variables of coastal home garden farmers and explored the linkages between biodiversity and household livelihoods in terms of perceptions and practices by farmers. Constraints in the coastal home garden farming system as perceived by farmers and extension personnel were also studied. The study was conducted in homegardens of three coastal Agro Ecological Units (AEU 1- Southern coastal plains, AEU 3- Onattukara Sandy Plains and AEU 4- Kuttanad) of southern Kerala. 35 farmer respondents were chosen from the home gardens of selected panchayats, comprising 15 participants and 20 non-participants who had at least 25 cents. The total numbers of respondents for the study were 165 comprising 105 coastal home garden farmers, 30 Agricultural Officers and 30 Scientists. Within the framework of Participatory Technology Assessment and Refinement, a collaborative effort was made to select appropriate technology for the primary crops within specific AEUs. This encompassed the evaluation of technology for bittergourd in AEU 1, chilli in AEU 3, and cowpea in AEU 4. Furthermore, Front Line Demonstrations (FLDs) were conducted to showcase and validate KAU-proven technologies that were deemed suitable for these specific crops. The structural configuration in terms of dominance-biodiversity profile of crops in coastal home gardens of southern Kerala was studied under two aspects viz., numerical and economic dominance and the diversity profile of coastal homegardens in Kerala. The study revealed that in AEU 1, out of the 82 identified crops, the most dominant one was coconut (5.90) followed by bittergourd (5.81) whereas in AEU 3 a total of 78 crops were identified, of which the maximum dominance was noted with black pepper (5.65) followed by chilli (5.26). In AEU 4 a total of 85 crops were identified of which the maximum dominance was noted with cowpea (5.24). The study compared the mean diversity index across different AEUs and found that AEU 4 exhibited the highest diversity index at 1.547, followed by AEU 3 at 1.159, and AEU 1 at 1.058. When examining the crop-wise diversity profile of coastal AEUs, fruits had the highest diversity index at 0.998, followed by vegetables at 0.878, and spice crops at 0.850. Conversely, the lowest biodiversity index was recorded for tubers at 0.360 and ornamental plants at 0.357. In AEU 1, the maximum diversity index was observed for spices at 0.801, followed by vegetables at 0.770, and medicinal crops at 0.741, with tubers having the lowest diversity index at 0.350. In AEU 3 and AEU 4, the highest diversity index was noted for fruit crops at 1.181 and 1.164, respectively, while the lowest diversity index was recorded for medicinal plants at 0.225 and 0.226 respectively. One-way ANOVA analysis revealed no significant difference in crop diversity among selected AEUs, but there was a significant difference in crop-wise diversity for plantation crops, multipurpose trees, medicinal plants, tubers, and ornamental plants. In terms of region-wise biodiversity, the mid-regions had the highest diversity index at 1.433, while the courtyard of coastal home gardens had the lowest diversity at 1.117. The study on vertical diversification of crops in different coastal AEUs revealed that in AEU 1 maximum diversification was seen for banana with six levels of diversification whereas in AEU 3 maximum diversification was seen for banana and coconut with five levels of diversification. In AEU 4 the maximum diversification was seen for coconut and banana with four levels followed by cowpea and black pepper with two levels of diversification. The extent of horizontal diversification was also recorded and found that 40 % of the homegardens in AEU 1 had 5 tier diversification whereas in AEU 3, 60 % of the home gardens had 6 tier or more diversification. In case of AEU 4, 73.33% of the homegardens were having 6 and more tiers of diversification. The study revealed that a significant percentage (53.33%) of homegardens in all AEUs had six or more tiers of diversification. This study involved assessing the technology requirements for the top dominant crops in the selected AEUs. The study identified that in AEU 1, the maximum technology need was recorded with production practices of bittergourd (6.83), whereas in AEU 3, the highest technology need was noted with protection practices (leaf curl disease management) in chilli (6.67). In AEU 4, highest technology need was noted for production practices in cowpea (6.50). Based upon the technology needs of the dominant crops in different AEUs, FLDs were conducted in selected three homegardens on production aspects of bittergourd (AEU 1) and cowpea (AEU 4) and protection aspects for chilly (AEU 3). The FLD in all the AEUs of study clearly highlights that scientific approach in farming and correct use of technology in accordance to KAU POP will help the farmer to derive more profit through improved production. The B:C ratio for FLD studies on bittergourd cowpea was found to be higher (1.96 and 1.78) compared to farmers practices (1.37 and 1.42). Research showed that using scientific methods like KAU practices reduced leaf curl disease in chilli by 48.19%, emphasizing the importance of adopting these techniques. The study also examined how farmers adopted KAU practices. It was found that 77.14% of AEU 1 farmers had low adoption, while 74.29% of AEU 4 farmers had high adoption. In AEU 3, 51.43% had low adoption. The study also categorized farmers as innovators (0.95%), early adopters (16.19%), early majority (34.29%), late majority (32.38%), and laggards (16.19%). In the study, a reliable scale was developed to assess technology-related aspects in Kerala's coastal home gardens. The Single ANOVA tool helped choose indicators with a mean value below 4.49, resulting in 26 variables across 8 dimensions. For reliability, the odd-even split-half method was used, yielding a strong correlation of 0.846 for the half-test and 0.917 for the full test. Pearson's correlation coefficients also confirmed the scale's validity by exceeding 0.25 at a 0.05 significance level. The scale was administered to respondents and the results showed that participating farmers perceived economic dimensions (4.62), environmental dimensions (4.30), and psychological dimensions (4.31) as the most important. Non-participating farmers, on the other hand, considered economic dimensions (4.61), psychological dimensions (4.14), and human resource dimensions (4.12) to be significant. Extension personnel, in their evaluation, rated economic dimensions (4.28), human resource dimensions (4.04), and political dimensions (4.03) as the most important factors. Cluster analysis was done for different dimensions for different categories of respondents and it invariably shows interaction effects of different dimensions of technology. The analysis was done using Ward linkage with 26 indicators, representing 8 dimensions of technology in coastal homegardens. For participant farmers 3 clusters were identified. The first cluster comprised of 10 indicators viz., profit, sustainability, technical efficiency, interpersonal relationship, initial cost, bureaucratic support, perception of technology, coordination, supply chain and acquisition of information that showed strong association. The second cluster encompassed 12 indicators that demonstrated proficiency in areas such as credit access, effective decision-making, keen observability, viability, adept resource management, resource recycling capacity, reasonable price expectations, local resource utilization, ready availability, utilization of family labour, dependable delivery reliability, and skilled labour requirements. The third cluster, comprised of four dimensions, exhibited characteristics related to flexibility, strong social networking, effective budgeting abilities, and openness to utilizing open-source technology. Analysis of livelihood assets revealed that social assets scored the highest mean value (239.3) followed by human assets (227.3), physical assets (185.6), natural assets (172.3) and financial assets (176). ANOVA confirmed that there is significant difference between AEUs in case of all assets except human assets and Pearson correlation analysis was conducted to examine the strength and significance of the relationship between these variables. The results showed a moderate positive correlation (r = 0.311, p < 0.05) between total assets and biodiversity. This suggests that as the total assets of the communities increase, the level of biodiversity also tends to increase. The study delved into gender roles within various coastal home gardens, with a focus on dominant crops. In AEU 1, particularly in bittergourd cultivation, men were predominantly engaged in labour-intensive tasks like land preparation (54.29%) and drain preparation (85.71%). Women, conversely, played more active roles in activities such as weeding (51.43%), kitchen gardening (57.14%), and harvesting (51.43%). Both genders actively participated in operations like irrigation (62.86%), plant protection activities (57.14%), and post-harvest tasks (51.43%). In AEU 3, where chilli cultivation was highlighted, men took on tasks like drain preparation (62.86%) and fencing (74.29%), while women were prominently involved in sowing seeds (68.57%), planting seedlings (57.14%), plant protection (57.14%), kitchen gardening (54.29%), harvesting (74.29%), and post-harvest operations (62.86%). Both men and women contributed to activities like applying manure (62.86%) and fertilizers, as well as weeding (54.29%). In AEU 4, centered on cowpea cultivation, men primarily handled land preparation (60%). Interestingly, women took on most responsibilities related to cowpea cultivation including, applying manure (57.14%), sowing seeds (51.43%), planting seedlings (51.43%), applying fertilizer (57.14%), weeding (51.43%), kitchen gardening (57.14%), and harvesting (60%). Both genders were involved in applying irrigation (54.29%). A chi-square test assessed the significance of gender differences in home garden activities, revealing a strong association between gender and agricultural tasks. The calculated chi-square statistic was 192.78, surpassing the table value of 33.92 at a 0.05% significance level, affirming the substantial gender differences in home garden activities. The study identified a total of 22 constraints within coastal home gardens, which were rated by respondents. The most significant challenges reported by coastal home garden farmers were, lack of scientific knowledge (1031) followed by salinity issues (rated at 1010), flooding concerns (1008), ineffectiveness of plant protection methods at recommended dosages (rated at 969), insufficient knowledge about plant protection chemicals (960), the impact of climate change (948), and the absence of proper drainage systems (916), listed in descending order of importance. Key suggestions to improve coastal home gardens as perceived by farmers and extension personnel were, the creation of customized packages of practices tailored to the coastal home garden system, enhanced on-going support and guidance from extension agencies for the adoption of recommended scientific practices and the promotion of Farmer Producer Organizations (FPOs) to enhance post-harvest handling and marketing Social anthropogenic variables of coastal home garden farmers like age, education, gender, occupation, economic motivation, extension contribution, irrigation potential, information source utilization, credit orientation, training need, market orientation and adoption were also studied. In essence, the research revealed a multifaceted profile of dominance and diversity within the coastal home garden community. Furthermore, it outlined specific technology requirements, adoption patterns, and dimensions conducive to the development of coastal home gardens. Additionally, the study delved into aspects related to livelihood assets, gender roles, constraints, and provided valuable suggestions to promote the sustainability of coastal home gardens in the Kerala region.
Utilisation of male sterility and polyploidy for genetic improvement in targets spp.
(College of Agriculture,Vellanikkara, 2023-05-11) Shilpa, P; KAU; Sreelatha, U
Marigold (Tagets spp.) is a multifunctional annual crop which can be grown in wide range of climatic conditions. The area of this crop is being expanded with the wide use of marigold flowers in cosmetic, food coloring, poultry and pharmaceutical industries due to its high carotenoid content. Among 33 Tagetes species, African marigold (Tagetes erecta) and French marigold (Tagetes patula) are highly preferred for the commercial cultivation. Even though these two species together hold a large extent of area under cultivation in the country, prominent steps taken for the development of superior hybrids (inter varietal as well as inter-specific) from public sector is still narrower. One of the major reasons for this might be the complex flower structure of marigold as in any other Asteraceae crop. The way out from this problem is the utilisation of genetic male sterility that exists in Tagetes erecta. In this context, the study entitled “Utilization of male sterility and polyploidy for genetic improvement in Tagetes spp.” was undertaken in the department of Floriculture and Landscaping during 2019-2022. As a preliminary parental evaluation, 20 marigold genotypes with 12 testers (10 African marigold and 2 French marigold genotypes) and 8 male sterile lines were evaluated during 2019-20. The analysis on plant characters showed the superiority of the line KAU - Ms6 in terms of plant height (47.27 cm), plant spread (31.39 cm) and stem girth (2.98 cm) while Ms18 exhibited with the early flowering habit in terms of bud initiation (17.07 days) and 50 per cent flowering (24.33 days). Superiority with respect to floral characters viz., flower size and flower weight was observed in KAU - Ms42 (3.70 cm and 4.30 g respectively). The analysis on yield traits exhibited the superiority of the line KAU - Ms6 in terms of number of flowers (56.77) and yield per plant (119.91 g) while KAU – Ms42 with highest number of viable seeds per plant (60.17). The estimation of total carotenoids revealed that the line KAU – Ms18 produced maximum pigment (2.01 mg/g) while the lutein content estimated was highest in KAU – Ms5 (6.23 ppm). Among testers, KAU - M1 was marked with superiority in terms of plant spread (44.00 cm), stem girth (4.97 cm) and leaf area (47.14 cm2) while French marigold genotypes (KAU - M47 and KAU - M48) were recorded lowest plant height, spread, stem girth and leaf area. However, early flowering was noticed in the French marigold genotypes, KAU – M47 and KAU – M48, in terms of days to bud initiation (19.20 and 17.20 days respectively) and 50% flowering (22.67 and 32.00 days respectively), produced small sized flowers of 3.20 cm and 2.70 cm flower diameter and 1.27 g and 1.04 g flower weight respectively. Among the African marigold testers, KAU - M1 showed delayed flowering, large sized flowers (6.80 cm flower diameter) with highest flower weight (11.87 g). With regard to number of flowers and yield per plant, the genotypes KAU - M46 and KAU - M2 showed better performance (126.16 and 253.96 g/plant; 111.34 and 266.32 g/plant respectively). The estimated total carotenoids was maximum in KAU – M47 (4.86 mg/g) and lutein in KAU – M1 (10.23 ppm). The observations on the stem color and flower color revealed the difference among the genotypes. The flower color was almost similar for all the 8 genotypes (Orange N25 C and Orange N25 B) in male sterile lines, while in the case of testers, among African marigold types, almost all the genotypes were orange colored (Orange – N25 group), except KAU – M1 (Yellow 9 A) and KAU – M46 (White NN155 C). Based on the evaluation of parental genotypes, four lines (KAU - Ms6, KAU - Ms18, KAU - Ms24 and KAU - Ms42) and six testers (KAU - M1, KAU - M2, KAU - M4, KAU - M8, KAU - M40 and KAU - M47) were selected and a crossing block was established during 2020-21 in a line x tester model. The mean performance of twenty four hybrids highlighted the inter-specific hybrid ‘KAU - Ms6 x KAU - M47’ which showed very good hybrid vigour. The combining ability analysis revealed the best general combiners KAU - M47 for number of flowers and yield per plant (108.96 and 128.93 respectively) and KAU - M1 for yield per plant (42.07). Genotypes KAU - Ms18, KAU - Ms24 and KAU - M8 were estimated with highest GCA for total carotenoids (0.09, 0.17 and 0.09 respectively). According to RHS color chart, except in the case of interspecific hybrids, all the other crosses were found to be showing the flower color of ‘Orange – N25’ group with shade of A, B and C. The interspecific hybrids KAU – Ms6 x KAU – M47, KAU – Ms6 x KAU – M47, KAU – Ms24 x KAU – M47 and KAU – Ms42 x KAU – M47 showed double colored flower heads with shades of ‘Orange N25 B and Red 46 A’. The good specific combiners identified for number of flowers and yield per plant were KAU - Ms6 x KAU - M47 (86.17 and 207.65 respectively), KAU - Ms42 x KAU - M2 (41.26 and 125.14 respectively) and KAU - Ms18 x KAU - M40 (19.95 and 93.17 respectively). In terms of total carotenoids, KAU - Ms6 x KAU - M2, KAU - Ms18 x KAU - M4, KAU - Ms24 x KAU - M1, KAU - Ms24 x KAU - M40, KAU - Ms24 x KAU - M47, KAU - Ms42 x KAU - M2, KAU - Ms42 x KAU - M8 and KAU - Ms42 x KAU - M47 were estimated with best SCA. On the estimation of heterosis for number of flowers and yield per plant, the inter-specific cross KAU - Ms6 x KAU - M47 recorded superiority in terms of relative heterosis (RH – 254.87%), heterobeltiosis (HB – 159.48%) and standard heterosis (SH – 380.63%). Other crosses which exhibited significant SH for yield per plant were KAU - Ms18 x KAU - M1 (61.22%), KAU - Ms18 x KAU - M47 (60.74%), KAU - Ms24 x KAU - M1 (47.22%), KAU - Ms24 x KAU - M47 (36.47%), KAU - Ms42 x KAU - M1 (43.73%), KAU - Ms42 x KAU - M2 (70.93%) and KAU - Ms42 x KAU - M47 (38.88%). With respect to total carotenoid, the hybrid KAU - Ms18 x KAU - M4 exhibited highest significant heterosis (RH – 104.29%, HB – 11.89% and SH – 32.0%). Experiment on polyploidisation of male sterile lines (KAU - Ms6) using two different concentration of colchicine (0.05% and 0.1%) for 1, 3 and 5 hours was conducted. Among the treatments, the lower colchicine concentration for short duration (0.05% for 1 hour) resulted in highest survival of seedlings (37.00%) and potted plants (27.02%). The treatment with 0.05% colchicine for 1 hour exhibited the most dwarf, compact and sturdy plants compared to other treatments. The analysis of stomatal characters also revealed larger stomata and low stomatal density with higher concentration and duration of colchicine, with highest stomatal size of 35.97 μm length and 11.49 μm width. The lowest stomatal density was observed for the treatment 0.1% colchicine for 3 hours (107.39). The ploidy levels of the variants through flow cytometry detected tetraploids. From the overall performance the seed treatment with 0.05% for 1 hour could be observed as the best for tetraploid indction which recorded maximum survival of plants, compact sturdy growth and larger sized stomata. Vegetative propagation of male sterile lines through cuttings was experimented as an alternative to the sib-mating method of maintaining the male sterile lines. Herbaceous cuttings collected from KAU - Ms42 were treated with growth regulators NAA and IBA at 100, 200, 300 and 400 ppm concentrations. Among the treatments, of the highest per cent of rooting with good survival of plants in pots was observed with the NAA 300 ppm (50.83% and 74.12% respectively). Considering per cent rooting of cuttings and survival of plants after transplanting to pots, NAA 300 ppm could be recommended as the best treatment. The present investigation on “Utilisation of male sterility and polyploidy for genetic improvement in Tagetes spp.” resulted in two heterotic hybrids viz. KAU - Ms6 x KAU - M47 and KAU - Ms42 x KAU - M2, for loose flower as well as landscaping purpose while three hybrids for total carotenoid content (KAU - Ms24 x KAU - M40, KAU - Ms42 x KAU - M2 and KAU - Ms42 x KAU - M47).
Effectiveness of microfinance services for agri- enterprise development by the self help groups (SHGs) in kerala
(Department of Agricultural Extension, College of Agriculture,Vellayani, 2023-02-23) Reshma J Murugan; KAU; Sreedaya, G S
The present study entitled “Effectiveness of microfinance services for agro- enterprise development by the Self Help Groups (SHGs) in Kerala” was conducted with the objective to measure the effectiveness of microfinance services and to identify the sustaining as well as the impeding factors of microfinance services for agro- enterprise development by the Self Help Groups (SHGs) in Kerala. The study also measures the impact of microfinance services on the SHGs in terms of buying power, standard of living and propensity to save. The study was conducted in ex-post facto design, in the three purposively selected districts of the three zones of Kerala, namely, Thiruvananthapuram, Thrissur and Malappuram. Two blocks, from each of the selected districts, were identified through purposive sampling. Seven SHGs were selected from the selected two blocks of each district, through proportionate random sampling, forming 21 SHGs and ten members were randomly selected from each of these selected SHGs, constituting a sample size of 210 agripreneurs. Officials of Micro Finance Institutions (MFIs) supporting agro-enterprise development by SHGs of the three selected districts were also selected by random sampling forming a sample size of 30. Thus a total of 240 respondents from the three districts of Kerala constituted the sample size of the study. The data was collected through pretested interview schedules, focus group discussion, and delphi technique. The statistical tools used were frequency, percentage analysis, mean, standard deviation, factor analysis, correlation ,coefficient, principal component analysis, paired t test, independent samples t test, Garret ranking and Kendall’s coefficient of concordance. The effectiveness of microfinance services was the dependent variable and was measured using a scale developed for the purpose. The scale had five dimensions namely; microcredit, micro savings, delivery mechanism, repayment and training & advisory, which were delineated through factor analysis. The impact of microfinance services was measured by agripreneurs’ buying power, standard of living and propensity to save, the procedure developed for the purpose was used. Nineteen independent variables and nine intervening variables were selected after judges rating and relevancy scoring. The results revealed that the microfina nce services were found to be moderately effective for 52.38 per cent of the selected SHGs (11 SHGs) whereas it was found to be highly effective and least effective for 23.81 percent of the SHGs (five SHGs each) under study. An ‘independent samples t test’ conducted, to compare the entrepreneurial characteristics of the respondents of these two extreme categories, revealed that there was a significant difference in their entrepreneurial characteristics. This result indicated that the entrepreneurial abilities of the respondents largely influenced the effectiveness of microfinance services for agro enterprise development than other factors like the nature of agroenterprises which was usually selected through micro screening techniques. The Principal Component Analysis (PCA) of the five sub-dimensions of microfinance services indicated that, the first principal component accounted for the largest percentage variance in the microfinance services effectiveness scores of the SHG agripreneurs was contributed by the sub-dimension viz. ‘microcredit’ followed by ‘micro savings’ and ‘delivery mechanism’. Thus it was deduced that the ‘microcredit’ largely determine the effectiveness of microfinance services followed by the ‘micro savings’ and ‘delivery mechanism’. Impact of microfinance services on the members of SHGs, was measured in terms of buying power, standard of living and propensity to save. The average buying power of the respondents, before and after availing the microfinance services were Rs. 40872 (Forty thousand eight hundred and seventy two) and Rs.79879 (Seventy nine thousand eight hundred and seventy nine) respectively. The standard of living was measured in terms of nine dimensions like ‘employment days’, ‘food consumption pattern’, ‘housing type’, ‘clothing’, ‘health care’, ‘education of children’, ‘assets creation’, ‘hygiene and sanitation’ and ‘recreation’ using the procedure developed for the study. Before the commencement of microfinance services, 34.28 per cent, 41.90 per cent and 23.81per cent of the members of SHGs belonged to low, medium and high standard of living classes respectively, whereas it was 24.28 per cent, 46.19 per cent and 29.52 per cent respectively after availing the microfinance services. The propensity to save was measured in terms of number of ‘savings accounts’, ‘fixed deposit accounts’, ‘recurring deposit accounts’, ‘postal savings accounts’ and ‘chit fund accounts’ of the respondents before and after availing the microfinance services. The result also indicated that out of the different accounts, there was a sharp increase of 28.10 per cent in the ‘chit fund’ accounts of the SHG members after availing the microfinance services. The correlation analysis indicated that among the personal socio psychological characteristics, ‘age’ of the SHG members was negatively and significantly correlated with the effectiveness of microfinance services at five per cent level of significance. The variables such as ‘training received’, ‘deferred gratification’, ‘social capital’ and ‘assertiveness’ were positively and significantly correlated with the effectiveness of microfinance services at one per cent level of significance whereas ‘annual income’, ‘experience with microfinance services’ and ‘information seeking behaviour’ were positively and significantly correlated with the effectiveness of microfinance services at five per cent level of significance. The correlation analysis of the entrepreneurial characteristics of the SHG members and the effectiveness of microfinance services revealed that ‘achievement motivation’, ‘innovativeness’, ‘thrift tendency’, ‘strategic visioning’ and ‘internal locus of control’ were positively and significantly correlated with the effectiveness of microfinance services at one per cent level of significance, whereas ‘economic opportunism’ was positively and significantly correlated with the effectiveness of microfinance services at five per cent level of significance. It was also revealed that more than half of the SHG members (59.05%) were middle aged (35-50), three fourth were women (76.19%) and almost half were falling under high school level of education (47.14%). Majority of the respondents had medium ‘annual income’, ‘training received’, experience with microfinance services’, ‘indebtedness’, ‘deferred gratification’, ‘problem solving ability’, ‘social capital’, ‘assertiveness’, ‘information seeking behaviour’, ‘sense of empowerment’, ‘economic opportunism’, ‘achievement motivation’, ‘innovativeness’, ‘thrift tendency’, ‘strategic visioning’ and ‘internal locus of control’. The intervening variable group dynamics was measured using group characteristics namely, ‘group cohesion’, ‘adherence to group norms’, ‘group leadership’, ‘group interaction’, ‘team work’, ‘transparency’, ‘group achievement’, ‘decision making procedure’ and ‘need satisfaction’. Based on the group dynamics index, majority of the SHGs (66.67%) maintain medium ‘group dynamics’ followed by less (19.05%) and high (14.29%). There was a positive and significant correlation between the group dynamics and the effectiveness of microfinance services at one per cent level of significance. The inventorisation of Micro Finance Institutions in the three districts was done from the microfinance officials selected for the study and from the lead banks of the respective districts. It was observed in the study that the finance for SHGs were prominently provided by nationalized banks and Regional Rural Banks, even though there exist other options like small finance banks, private banks etc. The sustaining and impeding factors of microfinance services as perceived by the agripreneurs were identified through Delphi technique and its ranking was done through garette ranking. The sustaining factors identified were lower interest rate compared to other sources of finance (65.79), lack of collateral security (62.23), timely finance assistance for enterprise development (58.22), opportunity to self-employment (55.90), attainment of additional skills (41.27), easily available services (39.81) and less paper work on availing loans (39.10) and these were ranked from first to seventh positions respectively by agripreneurs. Inadequacy of loan amount (76.86) was the major impeding factor identified. Insensitivity of MFIs to the type of enterprises, business cycle and clients’ social economical and personal circumstances (65.90) was the next major impeding factor. The other factors viz., difficulty in maintaining group cohesion (53.66), unfair attitude of the officials involved in microfinance (51.38), failure to treat clients as individuals in repayment (47.58) and pressure of weekly repayments and savings (47.00) were ranked third, fourth, fifth and sixth respectively. The least ranked impeding factors were high transactions cost of microfinance services (32.06) and savings could be spent in repaying of loans of defaulters (24.49). The sustaining factors of microfinance services as perceived by officials were economic empowerment (68.30), creation of employment opportunities (67.70), women empowerment (66.50), rural upliftment (51.57), increased household income (44.63), better standard of living (42.63), creation of assets (32.30) and less number of borrowers falling in debt traps (26.37) and were ranked from first to eighth rank respectively. The study exposed that the major impeding factors as perceived by micro finance officials were defaults in repayments (67.40), over borrowing (66.60) and multiple lending (66.17), diversion of loan money to unproductive activities (65.37), poor adherence to rules and regulations (46.57), poor sustainability of SHGs (43.57), anticipation of SHGs in the writing off the loan amount by the MFIs (40.80), lack of product diversification (39.87), Lack of financial literacy (34.73) and lack of research and development (31.00) and these were ranked from first to tenth rank respectively. The suggestions for improving the microfinance services were collected from the agripreneurs and were ranked by Kendal’s coefficient of concordance. Restructure of loan repayment including fixation of payback period and provision of grace period for certain entrepreneurial activities (1.31), fixation of EMIs based on business cycle/season (2.31), release of loan as per client demand (4.05), lower interest rate for loans (4.26), more skill oriented trainings for SHGs (4.48), timely and quick disbursement of loans (4.90), providing trainings on management and marketing skills (7.00), high interest rate for deposits of SHGs (7.69), mutual support of SHGs in product marketing (9.42), MFIs should ensure the clients’ ‘rights’ to know regarding all the procedures and acts in microfinance services (9.58) and for innovative products, the risks of entrepreneurs should be taken into account by the officials (11.00) were ranked from first to eleventh positions respectively. The suggestions for improving the microfinance services were collected from the officials of MFIs and were ranked by Kendal’s coefficient of concordance. Proper utilisation of loan amount (1.97), eliminating the practice of multiple borrowing (2.00), ensuring better performance of SHGs by the utilization of advanced technologies (2.03), availing benefits of all the available Government schemes (4.97), federation of SHGs (5.00), capacity building (5.03), awareness creation on financial planning (7.97), enhancement of the social capital (8.34), digitisation of records (8.72) and market survey before commencement of the enterprise (8.97) were the suggestions ranked from first to tenth positions respectively. The study revealed that the microfinance services were found to be more effective for SHG members having good entrepreneurial characteristics and group dynamics. The nature of enterprise was crucial only for certain enterprises, as most of the enterprises were selected by micro screening techniques. The microfinance services had a positive impact on buying power, standard of living in terms of health, hygiene and sanitation, education, recreational facilities and the propensity to save. The major impeding factor was inadequate loan amount and insensitivity of microfinance services to nature of enterprises and business cycle. Interestingly, study revealed that the rate of the possession of assets like smart phone, television, refrigerator and vehicle was more compared to washing machine and grinder which revealed that though microfinance services play a pivotal role in the women empowerment and gender equity, the drudgery of women is still to be addressed. The study recommends financial literacy programmes and establishment of business schools for youth to develop their entrepreneurial traits. The commercial banks need to train members of SHGs on proper financial management. Strong Governmental intervention in private chit funds is required to protect the members of SHGs from exploitation as they preferred chit funds than any other saving methods after availing microfinance services.
Modeling the Impact of Climate Change on Net Primary Productivity (NPP) of Selected Forest Ecosystems in Nilgiri Biosphere Reserve,India
(Department of natural resource management, College of forestry ,Vellanikkara, 2023-01-11) Srinivasan, K; KAU
As an inevitable component of global terrestrial ecosystem, vegetation plays a crucial role in energy transfer, carbon cycle, water balance and climate regulation. Its response to environment change has been considered as one of the key fields of ecological research. Net primary productivity (NPP) is defined as the net amount of carbon taken in by plants via photosynthesis, and is equal to the difference between the carbon assimilated during photosynthesis and that released during plant respiration. The present study tried to investigate mainly the following events: i) Land use and land cover changes over the NBR, India over 18 years (2000 to 2018) using MODIS data wherein, we, estimated the LULC of NBR, identified the changes in LULC in 18 years, and checked the accuracy of the LULC of 2018 with ground truth data using kappa coefficient. In the study, the importance of monitoring of LULC changes is revealed by the decrement in areas of closed shrub lands and grasslands during the period 2000-2018. Also, the human activities within the buffer regions of the NBR were understood by the increment of areas of classes like croplands and cropland/natural vegetation mosaics during the study period; Secondly, (ii) Assessed the impact of climate change on NPP over NBR during the period (1981 to 2019): wherein, The NPP that were expected to realize in location as well as in different forested ecosystems of the region were estimated through satellite derived data using CASA model. The data taken for modeling study was for a period of 38 years i.e., from 2018 to 2019. It was observed that the mean NPP of NBR was ranging from 47.2 to 183.73 (g C m-2 month-1). NPP trend ranged from (-0.154 to 0.176) for the period. Seasonal NPP of post monsoon season (ON) showed an increasing trend of NPP highlighting the positive influence of precipitation on NPP. During the study period, the trends observed per year were 0.14 W m-2 decrease in solar radiation, 0.02 0C increase in Air temperature, 0.10 mm increase in Precipitation and 0.06 g C m-2 month-1 increase in NPP respectively. Moreover, the estimated NPP showed spatial variation across the region of different LULC. Very large NPP (>103 g C m -2 month -1) for Evergreen Broadleaf Forest together with its smaller counterpart (57 g C m -2 month -1) for Persistent Wetlands were estimated over study region among different LULC. Highest overall mean NPP was in the order EBF>CNVM > DBF=MF>WS; and finally we, predicted the present and future NPP (2018 to 2028) using SARIMAX (0, 0, 2) (1, 1, 0) time series model using the output of CASA model. We divided the data sets in to two parts viz., 1981 to 2018 and 2010 to 2018; first set to build the model (R 2 = 0.552) and the second set for validation of the fitted model. We took data 1981-2010 and forecasted the NPP for the rest Eight years taking the air temperature, precipitation and solar radiation (2010 - 2018) and compared with the observed values of NPP (CASA derived NPP from 2010 to 2018). As there was good correlation between the observed and the predicted (8 years) (r = 0.63), hence validated the model and used for future prediction. As there were no explanatory variables for prediction (Ten years), hence assumed that the same trend for each explanatory variable for next Ten years to make the forecast of NPP and hence fitted individual ARIMA model for each of the explanatory variables (Seasonal ARIMA) viz., solar radiation, air temperature and precipitation. Later on, We used the SARIMAX(0, 0, 2) (1, 1, 0) model for prediction using the forecasted individual explanatory variables for Ten years and finally derived equation for predicted NPP using estimate for lag values as mentioned in the model fit statistic of NPP based on SARIMAX (0, 0, 2) (1, 1, 0).
Bio-elicitation of Ashwagandha (Withania Somnifera (L.) Dunal) for improved growth, yield and secondary metabolite production
(Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Agriculture,Vellayani, 2024-10-10) Manisha Elza Jacob; KAU; Deepa, S Nair
The study titled “Bio-elicitation of Ashwagandha (Withania somnifera (L.) Dunal) for improved growth, yield and secondary metabolite production” was carried out in the Department of Plantation, Spices, Medicinal and Aromatic Crops, College of Agriculture, Vellayani, during December 2019 to September 2023 with the objective to study the effect of individual application of chitosan and the root endophytic fungus, Piriformospora indica and their combined application on plant growth, yield and secondary metabolite production in Withania somnifera. The study was carried out in W. somnifera as four experiments (i) Biopriming of seeds using chitosan, (ii) Bio-elicitation by foliar application of chitosan, (iii) Bio-elicitation using P. indica, and (iv) Bio-elicitation by combined application of chitosan and P. indica. The second experiment consisted of two parts, preparation of chitosan nanoparticles and foliar application of chitosan. In the first experiment, seeds of Ashwagandha were primed with fourteen treatments, comprising of four different concentrations of chitosan (0.5 mg mL-1, 1 mg mL-1, 2.5 mg mL-1, and 5 mg mL-1) for three different durations (2 h, 4 h and overnight), along with overnight hydropriming and control (without priming). Different germination and seedling growth parameters of the seeds and seedlings were recorded. The highest germination per cent (76.00) and survival per cent (73.33) were observed in the priming treatment chitosan 5 mg mL-1 for 4 h. This was on par with the treatment chitosan 5 mg mL-1 for 2 h (69.33) and hydropriming treatment (70.67) with respect to germination per cent. Hydropriming recorded the highest germination index (1.79) and the treatment chitosan 2.5 mg mL-1 for 2h recorded the highest allometric index (0.91). Respective results were on par with the priming treatment chitosan 5 mg mL-1 for 4 h. Hydropriming recorded the lowest mean germination time (8.83 days). The highest values of seedling vigour indices I (8890.00) and II (45.15) were also recorded in the treatment chitosan 5 mg mL-1 for 4 h. The duration of priming had a significant effect on seedling growth parameters. Overnight priming treatments with chitosan were found to have an inhibitory effect on germination and seedling growth parameters with values on par with or lower than that of the control. Based on the results, seed priming with chitosan 5 mg mL-1 for 4 h, was selected as the best priming treatment for further experiments in the study. The preparation of chitosan nanoparticles was carried out by ionotrophic gelation method by dropwise addition of tripolyphoshate (TPP) solution to chitosan solution, under stirring at room temperature. Eighteen treatments formed by three levels of chitosan (1 mg mL-1, 2 mg mL-1 and 3 mg mL-1), three levels of TPP (0.5 mg mL-1, 0.75 mg mL-1 and 1 mg mL-1) and two speeds of rotation (700 rpm and 800 rpm) were tried for preparing the nanoparticles. The absorption spectra of the resultant solutions were observed at eight different wavelengths, i.e., 200 nm, 220 nm, 240 nm, 260 nm, 280 nm, 300 nm, 320 nm and 340 nm. The factor combinations with chitosan 1 mg mL-1 and TPP 0.5 mg mL-1 at 700 rpm, chitosan 2 mg mL-1 and TPP 0.75 mg mL-1 at 700 rpm, and chitosan 3 mg mL-1 and TPP 1 mg mL-1 at 700 rpm had an absorption peak at 220 nm. These were further characterized for particle size and were observed to have mean particle sizes of 222.9 nm, 333.4 nm and 366.9 nm, respectively. As the particles formed by various chitosan - TPP combinations did not fall in the nanoscale range of less than 200 nm, the further experiments involving chitosan nanoparticles were carried out using commercially available chitosan nano particles of size 80 to 100 nm. In the experiment involving foliar application of chitosan, seeds primed with the best priming treatment selected (chitosan 5 mg mL-1 for 4 h) were sown in protrays and thirty-day old seedlings were transplanted to growbags. The eight treatments in this experiment consisted of chitosan and chitosan nanoparticles spray, each at three different concentrations (1 mg mL-1, 2.5 mg mL-1 and 5 mg mL-1). The primed and non-primed seeds (absolute control) without any foliar spray application served as the control treatments. The treatments were imposed as foliar spray at transplanting, 15, and 45 days after that. The treatment with chitosan 2.5 mg mL-1 was found to be the best in terms of parameters like plant height, number of leaves and leaf area, recording the values 123.67 cm, 178.83 leaves and 119.99 cm2 respectively, at harvest. The treatment with a higher concentration of chitosan nanoparticles (5 mg mL-1) recorded the lowest number of days to flowering from transplanting (30.67 days), and also a lesser number of days to fruitset from flowering (9.17 days). The highest number of branches (9.97) and flowering branches (8.15) at harvest were observed in the treatment, chitosan 1 mg mL-1. The treatment with the lowest concentration of chitosan nanoparticles (1 mg mL-1) recorded the lowest values in various growth parameters, viz., plant height, number of branches, number of flowering branches, leaf area and collar girth. With respect to biochemical parameters, the highest content of total proteins (7.12 mg g-1) and carbohydrates (22.41 mg 100 g-1) were observed in the treatment with chitosan nanoparticles 2.5 mg mL-1 at harvest. The treatment with chitosan 1 mg mL-1 recorded the highest peroxidase (32.35 U mg-1 protein), catalase (17.57 U mg-1 protein) and superoxide dismutase (1.68 U mg-1 protein) activities. Similar to growth parameters, chitosan 2.5 mg mL-1 recorded the highest leaf area index (25.75) and leaf area duration (1020.92 days). All the treatments involving chitosan as well as chitosan nanoparticles were observed to have significantly higher photosynthetic rate at harvest. The highest stomatal conductance (162.97 mmoles m-2 s-1) was observed in the treatment chitosan 1 mg mL-1, the highest proline content (44.03 μM g-1 tissue) was observed in the treatment chitosan nanoparticles 2.5 mg mL-1, and the highest cell membrane integrity (91.80 per cent) was observed in chitosan nanoparticles 5 mg mL-1 at harvest. This treatment also had the highest total chlorophyll content at harvest. The shoot weight was observed to be significantly higher in chitosan treatments over chitosan nanoparticles as well as the control treatments. However, with respect to the dry weight of shoot, the lowest concentration of chitosan nanoparticles (1 mg mL-1) was observed to be on par with chitosan foliar spray treatments. The treatments with chitosan nanoparticles were observed to give significantly higher berry weight and seed yield per plant over chitosan and control treatments. The root parameters, viz., root length, root diameter, root volume and root yield (fresh and dry) were also observed to be significantly higher in treatments with chitosan nanoparticles over that of chitosan and control treatments. Root being the officinal part of the plant, the secondary metabolite, withanolide content in it was recorded. The highest withanolide content was observed in the treatment chitosan 2.5 mg mL-1 (0.45 per cent), and was on par with the treatment chitosan 5 mg mL-1 (0.43 per cent). Withanolide yield per plant was the highest in the treatment chitosan nanoparticles 2.5 mg mL-1 (5.46 mg plant-1) which had 4.4 times increase in withanolide yield over control. This was on par with the treatment chitosan 5 mg mL-1 (4.99 mg plant-1) which had 3.9 times increase in withanolide yield over control. Among the foliar spray treatments, chitosan 5 mg mL-1 and chitosan nanoparticles 2.5 mg mL-1 were selected as the best two treatments in terms of higher withanolide yield, for proceeding to the combination trials. In the experiment involving application of P. indica, P. indica mycelium, culture filtrate and cell wall extract were applied to the plants raised from primed and non-primed seeds. The seedlings raised from the primed and non-primed seeds were transplanted at 30 days after sowing to growbags. P. indica mycelium was applied at transplanting; and P. indica culture filtrate and cell wall extract were applied as foliar spray at transplanting, 15 and 45 days after transplanting. With respect to growth parameters, the highest plant height (120.19 cm), number of flowering branches (7.25), leaf area (111.84 cm2) and collar girth (2.67 cm) were observed in the plants derived from primed seeds treated with P. indica mycelium. Significantly higher protein content and defense enzymes were observed in the plants raised from non-primed seeds treated with P. indica cell wall extract. Physiological parameters like leaf area index and leaf area duration were found to be the highest in the plants raised from primed seeds treated with P. indica cell wall extract (1.40 and 21.65 days) at harvest. The highest stomatal conductance (129.30 mmoles m-2 s-1), photosynthetic rate (26.60 μCO2 moles m-2 s-1), proline content (45.37 μM g-1 tissue) cell membrane integrity (70.06 per cent) and total chlorophyll content (2.44 mg g-1 fresh weight) were recorded in the plants raised from primed seeds treated with P. indica mycelium. Shoot weight per plant was found to be significantly higher in plants raised from both primed and non-primed seeds treated with P. indica mycelium. Number of berries per plant, berry weight and seed yield per plant were found to be significantly higher in plants raised from primed seeds treated with P. indica mycelium and culture filtrate. All the root parameters, root length, root diameter, root volume, root yield per plant (fresh and dry) were observed to be the highest in plants raised from primed seeds treated with P. indica mycelium. The withanolide content was observed to be significantly higher in the roots of plants raised from primed seeds treated with P. indica mycelium (0.35 per cent) and culture filtrate (0.37 per cent). The same treatments showed significantly higher withanolide yield of 4.05 mg (3.82 times increase over control) and 3.60 mg per plant (3.28 times increase over control), respectively. Thus, the plants raised from primed seeds treated with P. indica mycelium and culture filtrate were selected as the best two treatments in terms of higher withanolide yield, for proceeding to the combination trials. For the combined application of chitosan and P. indica, the best two treatments selected from the individual application of chitosan and P. indica were used for studying their combined effect on growth, yield and secondary metabolite production in W. somnifera. The highest plant height (91.86 cm), number of leaves (143.70), leaf length (17.01 cm), leaf breadth (9.48 cm), and leaf area (113.28 cm2) were observed in the combination treatment of chitosan 5 mg mL-1 and P. indica mycelium. The highest number of branches (8.25), flowering branches (7.60) and collar girth (2.42 cm) were observed in the combination treatment involving chitosan 5 mg mL-1 and P. indica culture filtrate. The same treatment recorded the highest protein content (8.45 mg g-1). The highest peroxidase activity (34.74 U mg-1 protein), catalase activity (14.67 U mg-1 protein) and superoxide dismutase activity (1.48 U mg-1) were observed in the treatment involving chitosan of 5 mg mL-1 and P. indica mycelium. The same treatment recorded the highest value with respect to physiological parameters, viz., leaf area index (19.53), leaf area duration (803.07 days), stomatal conductance (137.11 mmoles m-2 s-1), photosynthetic rate (33.73 μCO2 moles m-2 s-1) and total chlorophyll content (3.76 mg g-1 fresh weight). The highest proline content was recorded in the treatment involving chitosan nanoparticles 2.5 mg mL-1 and P. indica mycelium (34.22 μM g-1 tissue) and highest cell membrane integrity in the combination treatment of chitosan nanoparticles 2.5 mg mL-1 and P. indica culture filtrate (83.69 per cent). The shoot weight and all the root growth parameters, viz., root length, root diameter, root volume and root yield were found to be the highest in the combination treatment of chitosan 5 mg mL-1 and P. indica mycelium. The combination treatments involving chitosan nanoparticles 2.5 mg mL-1 and P. indica mycelium/culture filtrate had the highest number of berries, berry weight and seed yield per plant. Significantly higher withanolide content was observed in roots of the plants treated with chitosan 5 mg mL-1 and P. indica culture filtrate. Withanolide yield per plant was the highest in the treatment comprising chitosan nanoparticles 2.5 mg mL-1 and P. indica culture filtrate and was on par with the combination treatment of chitosan 5 mg mL-1 and P. indica mycelium/culture filtrate. In the study, it was observed that all the combination treatments gave better performance than the control in terms of root yield, withanolide content and withanolide yield per plant. The concentration of chitosan and exposure time of priming had a profound influence on seed germination and seedling growth parameters in W. somnifera. The bio-elicitors, chitosan/chitosan nanoparticles and P. indica when applied individually and in combination to chitosan primed seeds have been observed to enhance growth, yield and metabolite production in a dose dependent manner in W. somnifera.

1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

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