1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1
Browse
7 results
Search Results
Item Functional trait variations and drought tolerance among teak (Tectona grandis Linn.f.) provenances(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2024-11-27) Muhammed Ajsal, K K; Delphy RochaThe present study investigated, functional trait variations among six provenances of Tectona grandis L. f, in the 90 year old provenance trial plot at Aravallikavu, Nilambur consisting of Anamalai, North Burma, Nilambur, South Bombay, South Burma and Travancore provenances. In addition, genetic diversity among these six teak provenances using ISSR markers and drought tolerance of these six provenances were also studied. Functional traits such as height, GBH, crown width, and self-pruning activity of teak provenance showed significantly different variation. However, leaf thickness not showed significantly different variations among the provenances. The South Burma provenance showed highest height (28.48m), crown width (9.05m) and self-pruning activity (0.82), whereas Nilambur provenance showed highest GBH of 168.06cm. The South Burma provenance showed highest stem straightness. In addition, foliar nitrogen concentration showed significantly different variations among the provenances. South Bombay provenance showed highest leaf nitrogen concentration of (2.54%). However, both phosphorous and potassium concentration did not significantly vary among provenances. Genomic DNA from six teak provenance was extracted using the modified CTAB protocol, yielding DNA concentrations ranging from 117.3 to 284.11 ng µL-1, with OD260/280 values between 2.06 and 2.21. Amplified bands resulted in 37 observed alleles, of which 32were polymorphic, demonstrating genetic diversity, while 5 were monomorphic. The Jaccard dissimilarity coefficient between Anamalai and South Bombay was 0.43, suggesting their genetic similarity. Whereas highest dissimilarity was observed between South Bombay and South Burma with coefficient of 0.67. Morpho-physiological and biochemical responses of teak ramets to drought stress were evaluated. Based on morphological indicator (percent leaf retained), Anamalai and South Bombay provenances were classified as "moderately Tolerant," whereas South. Burma was "Susceptible". Photosynthesis varied, with South Bombay maintaining the highest rate (3.27μmol CO2 m-2 s-1) and Travancore exhibiting the lowest (1.75μmol CO2 m-2 s-1) under xvi drought. Provenance displayed diverse responses under drought for relative water content (56.61%- Travancore to 84.62%-South Bombay) and total chlorophyll content (4.94 mg g⁻¹ South Bombay to 2.84 mg g⁻¹-Travancore). Maximum proline was produced by South Bombay (9.11μg g-1). Similarly, South Bombay displayed higher peroxidase activity (8.53μmol min-1). Hierarchical cluster analysis categorized teak provenances into Susceptible (Nilambur and Travancore), Moderately Tolerant (North Burma and South Burma), and Highly Tolerant (Anamalai and South Bombay) categories. The study enhances understanding of the functional trait, genetic variations and drought tolerance of six teak provenances contributing valuable information for breeding programs and sustainable forest management. The multidisciplinary approach integrating physiological, biochemical, and genomic analyses offers a comprehensive framework for understanding and improving teak cultivation, ensuring sustainable production in the face of environmental challenges.Item Stress proteomics on the application of defense hormones in swietenia macrophylla king seedlings(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2025-01-13) Karthik, K C; Manju Elizabeth ,PClimate change poses severe challenges to ecosystems, agriculture, and forestry by intensifying extreme weather events like droughts, floods, and heat waves, compromising plant health, productivity, and ecosystem stability. Additionally, climate induced salinity stress, driven by rising sea levels and increased irrigation, disrupts plant water and nutrient absorption, stunts root growth, and causes ion toxicity, reducing forest productivity, especially in tropical and subtropical regions. In response to these stresses, plants activate intricate defense mechanisms that mitigate damage and facilitate adaptation to adverse conditions. The defense hormones like Jasmonic Acid (JA) and Salicylic Acid (SA) play a vital role in enhancing plant resilience by regulating the expression of stress-related genes, promoting the production of protective proteins, and initiating physiological adjustments that optimize water-use efficiency and sustain cellular balance. This study investigated the effects of defense hormones, JA and SA, on mahogany seedlings, a species valued for its rapid growth, high-quality wood, workability, and durability. The research aimed to understand the role of JA and SA in alleviating drought and salinity stress and explore the associated stress proteomics, offering valuable insights into adaptive responses and resilience of mahogany seedlings to abiotic stress. The effects of various concentrations of JA and SA on the growth and development of six-month-old mahogany seedlings were investigated. Seedlings were treated with foliar applications of JA and SA at six different concentrations (0.2 mM, 0.4 mM, 0.6 mM, 0.8 mM, 1 mM and control), with measurements taken every 30 days over a 150-day period. The results indicated that JA at 0.6 mM (T4) and SA at 0.8 mM (T5) were the most effective treatments, leading to optimal growth performance. These treatments significantly enhanced overall plant vigor, promoting stability as indicated by the sturdiness quotient and improving seedling quality. The findings demonstrate the potential of JA and SA in enhancing mahogany growth, particularly under stress conditions, highlighting their promising applications in forestry practices. xviii The effectiveness of JA and SA in alleviating drought and salinity stress in mahogany seedlings was thoroughly examined. Drought stress was induced by withholding irrigation until wilting, while salinity stress was applied using a 100 mM NaCl solution (EC = 6 dS/m) over four days. Following stress induction, JA and SA were applied to leaves to enhance acclimatization and recovery, with measurements taken under normal, stressed, and 8-day post-hormone application conditions. Results indicated that JA at 0.6 mM significantly enhanced leaf retention and shoot production under drought and salinity stress conditions. It also improved photosynthetic rates and chlorophyll pigments during recovery compared to control seedlings. In contrast, control seedlings demonstrated higher proline accumulation during recovery from both stress types than those treated with SA and JA. The defense hormone JA at 0.6 mM is highly effective in alleviating drought and salinity stress, while SA (0.8 mM) was particularly effective against drought stress. Both hormones significantly influenced morphological, physiological, and biochemical adaptations in response to stress. A comparative proteomic analysis of mahogany seedlings was performed under normal, stress, and recovery conditions (48 hours post-hormone application). Results indicated that JA (0.6 mM) significantly influenced protein expression, effectively mitigating drought and salinity stress, while SA (0.8 mM) was particularly effective against drought stress. Each stress condition produced unique protein expression profiles, reflecting hormone-specific responses. Key proteins identified included Heat Shock Proteins and Heat Stress Transcription Factor 4a for drought stress, and Cation/H⁺ Antiporter and Guanine Nucleotide-Binding Protein for salinity stress, emphasizing their roles in enhancing stress resilience and recovery. xixItem Screening and QTL mapping for drought tolerance among the plus trees of Tectona grandis L.f.(Department of Forest Biology and Tree Improvement, College of Forestry ,Vellanikkara, 2024-03-23) Aswath, M N.; Santhoshkumar, A VThe present study investigated standardization of the Miniclonal propagation technique, assessing genetic diversity among accessions using ISSR markers, screening plus trees for drought stress and recovery, and discovering Single Nucleotide Polymorphisms (SNPs) through Genotyping by Sequencing in plus trees of Tectona grandis L. f. The study attempted to map the QTLs associated with drought tolerance, providing valuable insights into the genetic basis of this trait in teak. The effects of auxins on epicormic shoot production and rooting were evaluated to select the best hormone combination. The shoot production varied among the auxins and their concentrations. Indole-3-butyric acid (IBA) at 4000 mg L-1 showed optimal shoot production, enhancing rooting potential, with the highest rooting percentages observed at 49.19% for 4000 mg L-1 IBA and 41.71% for 3000 mg L-1 IBA. The cuttings treated with 1-Naphthaleneacetic acid (NAA) showed only 5.61 to 14.01% rooting, whereas a combination of IBA and NAA encouraged the callusing. The size of the cuttings affected the rooting potential, and the rooting percentage showed a significantly positive correlation with shoot diameter (r=0.89). Further, epicormic shoot and root production was observed to vary significantly among the accessions. Aravallikkavu (10.67) and Top slip-6 (8.33) exhibited the highest epicormic shoot numbers, while Nedumkayam-1 displayed minimal shoot production. Nellikutha-6 showed the highest rooting percentage (57.11%), contrasting with Nellikutha-2 (22.50%). Subsequently, ten accessions were successfully propagated for further investigations. Genomic DNA from ten accessions was extracted using the modified CTAB protocol, yielding DNA concentrations ranging from 166.7 to 269.4 ng μL-1, with OD260/280 values between 1.86 and 2.08. Amplified bands resulted in 212 observed alleles, of which 199 were polymorphic, demonstrating genetic diversity, while 13 were monomorphic. The Jaccard similarity coefficient between Topslip-6 and Topslip-10 was 0.361, suggesting their genetic similarity. Accessions 6, 4, 10, 8, and 7 displayed coefficients of 0.504, 0.476, 0.465, and 0.440, respectively, indicating close relationships. Morpho-physiological and biochemical responses of teak ramets to drought stress were evaluated, indicating varying tolerance levels among accessions. Based on morphological indicator (percent leaf retained), accessions Topslip-6, Topslip-10, and Shankaramthode-1 were classified as "Highly Tolerant," whereas Nellikutha-2 was "Highly Susceptible". Photosynthesis varied, with Topslip-6 maintaining the highest 2 m-2 s-1) and Nellikutha-2 exhibiting the lowest (1.200) under drought. Accessions displayed diverse responses under drought for Fv/Fm (0.819- Topslip-10 to 0.309-TC11) and chlorophyll content (1.573- Nedumkayam-1 to 4.342 - TC4). Maximum proline was produced by Topslip-6 -1), whereas -1 -1) produced minimal proline. Similarly, Accession 8 produced lower glycine content -1), and Topslip-10 exhibited -1. Cluster analysis revealed distinct groupings, with PCA aiding accession selection based on performance indices, categorizing teak accessions into Highly Susceptible (Nellikutha-2), Susceptible (Nedumkayam-2 and Nellikutha- 1), Moderately Tolerant (Topslip-6, TC4, Nedumkayam-1, and Shankaramthode-1), and Highly Tolerant (Topslip-10, TC11, and Topslip-6) categories. Genotyping based on Illumina-assembled genomic sequences for diverse accessions was carried out. Variant calling on ten genomes yielded 7,518,960 variants and filtered down to 3,665 SNPs. GWAS identified 19 significant SNPs linked to drought tolerance, supported by QQ and Manhattan plots. BLASTX and UniProt annotations unveiled genes associated with stress resistance, organ formation, and metabolic processes. QTLs on Chromosome_1 (BLH9, POX), Chromosome_4 (DXS, TKL), and Chromosome_11 (MFS, MIK2) were implicated in diverse physiological functions. BLH9 is implicated in plant organ and shoot formation, xylem development, morphogenesis, and meristem activity. DXS is involved in chlorophyll biosynthesis and terpenoid biosynthesis. MFS regulates stomatal closure, while MIK2 is associated with various cellular responses, including cellular and root activity. The study enhances understanding of the genetic basis of drought tolerance in teak, contributing valuable information for breeding programs and sustainable forest management. The multidisciplinary approach integrating physiological, biochemical, and genomic analyses offers a comprehensive framework for understanding and improving teak cultivation, ensuring sustainable production in the face of environmental challengesItem Soil nutrient dynamics in a second rotation monocropped teak plantations(Kerala Agricultural University, 2022) Santhosh, D T; Santhoshkumar, A VTeak is considered the most valuable tropical timber species and is known as the "King of Timber". Kerala has 76,710 ha of pure teak plantation and 14,440 ha of teak plus softwood planting, accounting for 49.08 and 9.24 percent of the state's total plantation area, respectively. Kerala's teak plantations productivity has been declining and a large-scale drop in teak plantation productivity in the replanted teak regions, referred to as ‘Second rotation decline’ is being observed. In this context, a field study on “Soil nutrient dynamics in a second rotation monocropped teak plantations” was conducted in selected plantations from Thrissur and Chalakkudy Forest Divisions to investigate the quantity and intensity of soil nutrients among second rotation teak plantations. The study site was divided into five age classes (0-10, 10-20, 20-30, 30-40 and 40-50 years) and 6 replications (sample plots) were laid out in each age class forming a total of 30 sample plots (6 sample plots x 5 age classes). Sample plots of size 24m x 24m were laid randomly and total tree height and girth at breast height were measured in the field. Surface soil (0-30cm) samples were collected from each plot. Teak foliage sampling was done by collecting the index leaf (second fully opened leaf from the bud). Ground vegetation sampling was carried out by harvesting all vegetation from randomly laid out 1m x 1m plots from each sample unit. Soil sampling was also carried out from open barren lands from both the forest divisions. The collected soil was analysed for physical properties like particle size distribution/texture and chemical properties like soil pH, CEC, exchangeable bases, extractable acidity, organic carbon, quantity and intensity factors of N, P, K, Ca, Mg, S, Na, Fe, Zn, Cu, Mn, Al, Ni, Cd, Pb and also the critical limits with reference to teak. Quantity of C, N, P and K were estimated from teak foliage and ground vegetation following standard procedures. The results showed that among the plantations studied in Thrissur and Chalakudy divisions, there were differences in terms of soil chemical properties in 100 plantations of different age classes. However, definite pattern of concentration of elements with respect to the age of the plantations was lacking. The intensity factors of nutrients too showed no pattern or trend with reference to the age of the teak plantations. The variation in ion concentration in soil solution was not influenced by the quantity or labile pool of the element. The soils from teak plantations were observed to have more concentration of nutrients compared to barren land. All the observed soil parameters were well within the range required for the optimal growth of teak. However, there was also variation in terms of the concentration of the elements. Attempts to relate soil parameters to site productivity yielded no relevant associations, implying that the decline in productivity may be due to poor management rather than nutrient depletion. There was significant management inconsistency among the plantations, which significantly influenced the potential utilization of site resources for optimal teak development. Significant variation in the content of C, N, P and K were observed in teak foliage of various age classes. A decrease in N, P, and K content was observed in the foliage with an increase in age. The content of C, N, P and K in the ground vegetation samples of different age classes showed no pattern in trend with respect to the age of the teak plantations. Further extensive studies on the soils from teak plantations in the state in terms of ion activity to obtain better knowledge in terms of nutrient deficiency and toxicity with a particular focus on improving productivity of teak plantations is also required. The results of this study also point to an imperative necessity to study other factors apart from soil that affect teak productivity.Item Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2022) Shifin S Ravuther; Binu N KamalolbhavanThe present study titled “Progeny testing and genetic diversity analysis in plus trees of Melia dubia Cav.” was carried out from 2020 to 2021 with the objective of progeny evaluation in 25 half sib plus trees identified from different part of Kerala, by studying the growth performance of its seed progeny planted at college of forestry germplasm field. The study also includes exploring the genetic diversity of these 25 plus tree seed progenies along with analysing the caryophyllene content, one of the economically important phytochemical compounds present in M. dubia. The plus tree seed progeny differed significantly in morphological traits like height, collar girth, volume and physiological parameters like photosynthetic and transpiration rate, stomatal conductance, chlorophyll content and relative water content. The progeny FCV-MD-03 of Tholpetty in Wayanad district performed better in growth parameters viz., height (5.61 m), collar girth (0.42 m) and tree volume of (0.017 m3 ). The variability study indicated that the morphological trait (volume) and physiological trait (stomatal conductance) exhibited higher PCV and GCV. From the heritability estimation it was observed that the most heritable morphological trait was collar girth followed by the plant height. For the physiological parameter, transpiration rate (0.91) was the most heritable trait followed by the chlorophyll content. These morphological and physiological traits were positively correlated implicating the significance of physiological parameters as source to identify better progeny. Path analysis on morphological trait has showed that the collar girth had the highest positive direct effect on the plant volume. Genetic variation study in 25 plus tree progenies using ISSR primer produced 164 amplicons which estimates viz., percentage of polymorphism (68%), polymorphism information content (0.70 to 0.83), Nei’s gene diversity (31%). The dendrogram obtained by using UPGMA classified the 25 accession of M. dubia into 2 distinct clusters. Cluster I constitute population from Wayanad and the rest of the 136 population in cluster II. Based on the genetic variation observed, superior seed sources can be identified and tree improvement programme could be developed for the conservation and further development of M. dubia. Standardization of HPLC for the quantification of caryophyllene phytochemical in M dubia was studied. Significant variation was observed for the total caryophyllene content for the different accession of M dubia seed progeny. The maximum quantity was observed in FCV-MD-08 (16.4 %) of Pothundy in Palghat district followed by FCV-MD-3 of Tholpetty in Wayanad.Item Genetic diversity and domestication of Pyrenacantha volubilis Wight, an anti cancer drug yielding plant(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2020) Arjun Ramachandran; Santhoshkumar, A VItem Field performance of arbuscular mycorrhizal fungi on vegetative growth of mahogany (swietenia macrophylla king.) seedlings(Department of Forest Biology and Tree Improvement, College of Forestry, Vellanikkara, 2018) Satyabrata Nayak; Santhoshkumar, A VA study was conducted to determine the efficiency of arbuscular mycorrhizal fungi (AMF) on the vegetative growth of mahogany (Swietenia macrophylla King.) seedlings under field conditions at College of Forestry nursery and Instructional farm of Kerala Agricultural University, Vellanikkara, Thrissur district, Kerala during 2015-2017. Three AMF species used in the study were Funneliformis mosseae (Fm), Acaulospora mellea (Am) and Glomus etunicatum (Ge). The study was carried out in two parts. The first experiment was conducted in nursery for three months and the second experiment was conducted in the field for six months. In the nursery experiment, the AMF were applied to the seedlings either individually or in combinations (Fm, Am, Ge, Fm + Am, Am + Ge, Ge + Fm, Fm + Am + Ge) at three different doses (5 g, 10 g and 15 g) and laid out in a factorial CRD with control as 21+1 treatment combinations and three replications. The purpose of the nursery experiment was to choose the best four treatments for out-planting in the main field. It was found that the AMF species used in the nursery significantly influence the biometric characters (height, collar diameter and number of leaves) of the seedlings when compared to control. However, the AMF treatments did not differ among themselves. There was significant differences among different doses of AMF. The seedlings growth increased when the doses of AMF increased. From the result, Fm (15 g), Am (15 g), Ge (15 g) and Fm + Ge (15 g) were chosen as treatments for seedlings for the second experiment. The field experiment was laid out in a randomized block design with five treatments (four chosen treatments from nursery + control) with three replications. The observations like height, collar diameter, number of leaves, photosynthesis rate, stomatal conductance, transpiration rate and leaf temperature were recorded at 30 days interval. Soil nutrient analysis was done before and after the planting of ii the seedlings. Plant’s nutrient analysis were done after the completion of the experiment. It was found that inoculation with AMF, did not result any significant differences in height, collar diameter, number of leaves, stomatal conductance and leaf temperature. However, the AMF had significant influence on photosynthesis rate and transpiration rate on the seedlings at later stages of the experiment. From soil nutrient analysis, it was found that total N, available P, available K and organic carbon content increased with AMF inoculation. The soil pH changed from 5.46 to 5.94. From plant nutrient analysis, it was found, that there were no significant effect of AMF on K and N content of the seedlings. However, the P and C content of the seedlings increased due to AMF. The root colonisation percentage and total spore count were found to be low in all treatments. These values were significantly higher in seedlings inoculated with AMF than the non-inoculated seedlings. From the study, it was concluded that increasing doses of AMF can increase S. macrophylla seedlings growth in nursery. The AMF did not affect the growth of seedling during first six months of field experiment. But, some physiological parameters like photosynthesis rate and transpiration were influenced by the AMF at later stages of the growth. It may be pointed to the fact that AMF experimented could not establish in the field as evidence by low root colonisation percentage. This may be because of the soil reaction which was acidic in nature and was not suitable for AMF to establish since AMF require neutral medium for its better growth and development. Arbuscular mycorrhizal fungi helped in improving the pH of soil along with other nutrient contents (N, P, K and organic C). The seedlings were benefitted from AMF as their P uptake was increased. Further studies are required to identify better native species of AMF for S. macrophylla in acidic ultisols of Kerala.