Browsing by Author "Gayathri, G"

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Assessment of genetic variability in fodder oats (Avena sativa L.) for yield and quality
(Department of Genetics and Plant Breeding , College of Agriculture, Vellayani, 2024-01-08) Annem Sethuvardhan Reddy; Gayathri, G
The current research program, entitled “Assessment of genetic variability in fodder oats (Avena sativa L.) for yield and quality.” involved the study of thirty fodder oat genotypes collected from AICRP Forage Crops and Utilization, Ludhiana Centre under Punjab Agricultural University. This research was conducted in the hill zone at the Regional Agricultural Research Station at Ambalavayal and the plains at the Instructional Farm in College of Agriculture, Vellayani, during Rabi 2022-23. The fodder oat genotypes were evaluated using a Randomized Block Design (RBD) with three replications. The primary objective of this investigation was to assess the genetic variability in fodder oats and develop a selection index for identifying accessions with high yield and nutritional quality. The fodder oat accessions were harvested during the milky stage of grain filling. Quantitative characters like days to first flowering, days to 50% flowering, number of tillers per plant, number of leaves per plant, green fodder yield per plot, dry matter yield per plot, leaf dry weight per plant, stem dry weight per plant, plant height, days to maturity, leaf-stem ratio, ratoon green fodder yield per plot, crude protein content, crude fibre content, total phenolic content, condensed tannin content, total antioxidant content and phytate content were recorded in all accessions. Statistical analyses, such as analysis of variance, genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability, genetic advance, correlation studies, path analysis, cluster analysis and discriminate function analysis were conducted to determine the extent of variation among the existing oat genotypes. The analysis of variance showed significant differences among the studied traits across different genotypes, indicating variability for effective selection. For green fodder yield in the hill zone, the genotypes OL-12, OL-1937, OL-1980, and OL-1963 performed the best with yield ranging from 8.78kg to 8.46kg per plot, while OL-13, OL-1949, and OL-1896 had the lowest yields ranging from 5.75kg to 6.15kg per plot. In case of plains, the highest green fodder yield was observed in JHO-822(3.5kg per plot). Regarding nutritional traits, OL-1931-1 had the highest crude protein content of 16.15 per cent, while OL-1963 had the lowest of 10.97 per cent. Maximum crude fiber content was in OL-1964 (28.02 per cent), and minimum in OL 1952 (15.97 per cent). Total phenolic content was highest in OL-11 and lowest in OL-1963. Condensed tannin content peaked in OL-15, and total antioxidant content was highest in OL 15 and lowest in OL-125. The anti-nutritional character phytate content was lowest in OL-1974 and highest in OL-1976-1. At Instructional Farm, Vellayani, only 12 genotypes managed to reach maturity stage, and their yield was significantly lower ranging from 3.5kg to 2.2kg plot, which was less than 50 per cent compared to the high ranges in Ambalavayal. Among these 12 genotypes, JHO 822 demonstrated superiority in all yield-contributing traits. Genetic variability parameters such as genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability (h2) and Genetic Advance (GA) were studied to find genetic variability present in the genotypes. In the present study, PCV is higher than GCV for all the characters that were recorded, indicating the role of the environment in the expression of these characters. High heritability coupled with high genetic advance was observed for the characters number of tillers per plant, number of leaves per plant, leaf dry weight per plant, stem dry weight per plant, plant height, leaf stem ratio, crude protein content, total phenolic content, condensed tannin content, total antioxidant content and phytate content, which indicates the presence of additive gene action and hence selection based on these characters will be effective for the genetic improvement of the genotypes. The correlation analysis revealed that the trait green fodder yield was correlated positively and significantly with number of tillers, number of leaves, dry matter yield per plot, leaf dry weight, stem dry weight and plant height was correlated negatively and significantly with trait leaf stem ratio. Path analysis divulged that a beneficial positive direct effect on green fodder yield was reported by days to 50% flowering, number of leaves, stem dry weight, leaf dry weight, plant height and days to maturity. While negative direct effect was recorded for days to first flowering, number of tillers, dry matter yield and leaf stem ratio. The residual effect in path analysis (phenotypic) was 0.3644, so about 63% of the total variation in GFY can be explained by the ten characters taken for study. The genetic diversity analysis classified the 30 genotypes into seven clusters following the Euclidean square method, with cluster I being the largest (14 genotypes), followed by clusters II (8 genotypes), IV (3 genotypes), III (2 genotypes), and clusters V, VI, and VII (1 genotype each). The maximum intra-cluster distance was observed in cluster IV, followed by clusters II, I, and III. The highest inter-cluster distance was observed between clusters IV and VII, followed by clusters I and VII. For a successful breeding program, genotypes should be chosen from clusters with the highest degree of divergence. The study found significant genotypic variation for all the examined characteristics. Based upon Selection Index score the genotypes OL-15, JHO-822, and OL-9 exhibited superiority in terms of yield and yield-attributing characteristics, ranking in the top three positions. These superior genotypes can be considered as potential parents for future breeding projects after assessing their combining ability or advanced to further trials for variety development.
Enhancing fruit set and yield of tomato (solanum lycopersicum L.) in polyhouse using artificial pollination and growth regulators
(Department of Vegetable Science, College of Agriculture , Vellayani, 2018) Gayathri, G; Rafeekher, M
Heterosis breeding in sesame (Sesamum indicum L.).
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Gayathri, G; Dijee Bastian
The study entitled ‘Heterosis breeding in sesame (Sesamum indicum L.)’ was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara. The objectives of the study were to collect and evaluate different genotypes of sesame for morphological traits and yield attributes, to identify useful parents producing heterotic crosses and developing hybrids in sesame. The study also intended to develop male sterile lines in sesame through interspecific hybridization with Sesamum malabaricum. Sesamum indicum and Sesamum malabaricum accessions were collected from Kerala and Tamil Nadu and evaluated for their morphological traits. Wide range of variation was noticed for characters like plant height, number of days to flowering and seed yield per plant which contributed maximum to genetic divergence. The genotypes studied were grouped into six clusters. High genotypic coefficient of variation (GCV) was recorded for number of capsules per plant, plant height, seed yield per plant and number of branches per plant. High heritability with high genetic advance as per cent of mean was recorded for number of days to flowering, plant height, number of branches per plant, number of capsules per plant and seed yield per plant. This indicates that the characters are governed by additive gene effects and selection for these traits will be effective. Association analysis revealed that seed yield per plant was correlated to plant height, number of capsules per plant and number of days to flowering. Path coefficient analysis indicated maximum positive direct effect by number of capsules per plant, capsule length, plant height and 1000 seed weight on seed yield per plant. In order to develop hybrids, fourteen parents were selected based on the per se performance of the genotypes. They were crossed in line X tester mating design. Forty eight hybrid combinations obtained were raised in the field along with the parents and evaluated for their heterosis and combining ability effects. Parental genotypes AVTS-06-5, AVTS-06-10, IVTS-06-12, KYM-1, Tilak and TMV-6 were identified as high combiners based on general combining ability (gca) effects. Two combinations viz. AVTS-06-5 X KYM-1 and IVTS-06-12 X TMV-3 had significant values of per se performance, specific combining ability (sca) effects and standard heterosis for seed yield per plant. They can be evaluated for their hybrid vigour over locations and seasons. The crosses AVTS-06-5 X TMV-3, AVTS-06-5 X TMV-6 and TCR 3279A X KYM-1 have been identified as potential cross combinations for isolation of promising segregants as the parents involved in these crosses had high significant gca effects for seed yield per plant but the hybrids recorded non significant sca effects. Interspecific hybridization between S.malabaricum and S.indicum was attempted to develop male sterile lines. Seed set was noticed in three interspecific hybrids which failed to germinate due to embryo abortion. Hence these embryos were rescued and raised in vitro to obtain the hybrids.
Identification of core set in fodder cowpea(Vigna unguiculata (L.) WALP) germplasm accessions
(Department of Plant Breeding and Genetics, College of Agriculture ,Vellyani, 2022-01-15) Amritha, Varanya; Gayathri, G
Identification of fodder Bajra (Pennisetum glaucum (L.) R.Br.) for yield and quality for AEU 8(southern laterite)
(Department of Plant Breeding and Genetics, College of Agriculture ,Vellayani, 2023-01-16) Byrapuram Arani Jyothi; Gayathri, G
Pearl millet (Pennisetum glaucum (L.) R. Br.) is a dual-purpose crop generally grown as a cereal or as fodder crop, belonging to family Poaceae, having chromosome number 2n=14. It is grown extensively as a fodder and grain crop during the Kharif season having low rainfall withstanding drought and adverse agro climatic conditions. Understanding the type and degree of variability present in the breeding materials as well as the extent to which the desired traits are heritable will help in achieving genetic improvement for quantitative trait in fodder bajra. In order to plan the breeding strategy of the crop, this requires clear knowledge of the inheritance pattern of the main quantitative traits that provide fodder. Therefore, the present research was conducted in order to comprehend the genetic variability present in the genotypes and inheritance pattern of various fodder yields and the contributing characteristics. The present study was undertaken for “Identification of fodder bajra (Pennisetum glaucum (L.) R. Br.) for yield and quality for AEU 8 (Southern Laterite)” was conducted at Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. 30 genotypes of fodder bajra collected from IIMR, Hyderabad were evaluated in Randomized Block Design with three replications. The present investigation was done for the assessment of the genetic variability and development of selection index in fodder bajra accessions for yield and nutritional quality. The crop was harvested at 50% flowering stage. Observations were recorded for various qualitative and quantitative characters, viz. Plant stand after germination, number of tillers per plant, number of leaves per plant, internodal length, days to first flowering, days to 50% flowering, green fodder yield per plot, dry matter yield per plot, leaf dry weight per plant, stem dry weight per plant, plant height, days to maturity, ratoon green fodder yield per plot, crude protein content, crude fibre content, total phenolic content, total flavonoid content, total antioxidant content. Statistical tools such as analysis of variance, genotypic coefficient of variation (PCV), phenotypic coefficient of variation (GCV), heritability, genetic advance, correlation studies, path analysis and cluster analysis were carried out to find out extent of variation present in existing genotypes. Analysis of variance revealed significant differences for all traits studied among the genotypes. This reveals the presence of variability among the genotypes and hence selection can be effective in the population. Maximum green fodder yield was recorded by the genotype 2021K-135 (8.96 Kg/plot), IIMRAVS6 (8.93 Kg/plot), IIMRAVS8 (8.68 Kg/plot) and 2021K-126(7.86 Kg/plot). Minimum green fodder yield was observed by the genotypes IIMRAVS11 (2.77Kg/plot), 2021K-OPB2 (3.76 Kg/plot) and 2021K-OPB1(4.08 Kg/plot). Ratoon green fodder yield was observed to be maximum in the genotypes 2021K-132 (3.11 Kg), 2021K-129(3.00) and IIMRAVS10(2.62 Kg). Minimum ratoon green fodder yield was noticed in the genotypes IIMR AVS 21(1.25 Kg), IIMRAVS11(1.38 Kg) and 2021K-137(1.39 Kg). Highest crude protein content was observed in the genotype IIMR AVS3 (15.40%), followed by IIMRAVS9 (13.65%) and IIMRAVS8 (12.95%). Lowest crude protein content was recorded in the genotypes 2021K-126 (4.50%), 2021K-137(4.550%) and 2021K-OPB2 (4.553%). Maximum crude fibre content observed in the genotypes IIMR AVS1 (50 %), 2021K-132 (49.5%) and 2021K-138 (49.0%). Minimum value was reported by the genotype 2021K-129(20.0%), 2021K-131 (20.0 %) preceded by the genotypes 2021K-140 (20.503%) and IIMRAVS8 (21.0%). Genetic variability parameters such as genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV). Heritability (h2 ) and Genetic Advance (GA) were studied to find genetic variability present in the genotypes. In the present study, PCV is higher than GCV for all the characters which were recorded, indicating the role of environment in the expression of these characters. The low PCV and GCV were recorded for days to 50% flowering, days to maturity, days to first flowering, number of leaves per plant, internodal length, plant stand after germination. Low PCV and GCV estimates for these traits indicate a narrow range of variability for these characters and limited scope for selection. High heritability coupled with high genetic advance was observed for the characters total antioxidant content, crude protein, total phenolics content, crude fibre, total flavonoids content, ratoon yield per plot, green fodder yield, dry matter yield, number of tillers per plant, leaf stem ratio and stem dry weight which indicates presence of additive gene action and hence selection of these characters will be effective for the genetic improvement of the genotypes. The correlation studies showed highly significant positive association of green fodder yield with number of tillers per plant, dry matter yield and leaf dry weight and positive association with plant height, number of leaves per plant, internodal length, stem dry weight and leaf stem ratio. The path-coefficient analysis suggested the importance of leaf dry weight dry matter yield, number of tillers per plant, internodal length and number of leaves per plant as they showed direct positive effect on green fodder yield. The genetic diversity analysis classified 30 genotypes into five clusters following Euclidean² method containing one to eleven genotypes. The cluster I was the largest (11) followed by cluster IV (10), cluster V (5), cluster II (3) and cluster III (1). Maximum intra cluster distance was observed in the genotypes falling under the cluster I followed by V and IV. Highest inter cluster distance was observed in the genotypes falling under the cluster III and V, followed by II and III. For a breeding programme to be successful, genotypes should be chosen from clusters with the highest degree of divergence. For all of the characters examined, the study found that there was a significant amount of genotypic variation. The genotypes 2021K-135, IIMRAVS6 and IIMRAVS8 were shown to be superior in terms of yield and yield-attributing characteristics. These superior genotypes can be used as parents in upcoming breeding projects or advanced for more trials for variety development.
Population structure analysis in stylo [Stylosanthes sp.] using SSR markers
(Department of Plant Biotechnology, College of Agriculture , Vellayani, 2022-10-27) Fathima Zahra ,P M; Gayathri, G
Stylosanthes is a dominant pasture legume growing in tropical and subtropical regions of India and is extensively applied as forage and cover crop in agricultural systems. The fundamental concern with Stylosanthes is the restricted number of superior varieties. The genus Stylosanthes under the family Fabaceae comprises approximately 50 spp. distributed worldwide in the tropics among which S. scabra, S. seabrana, S. hamata and S. guianensis are predominant. The current study entitled “Population structure analysis in Stylo [Stylosanthes sp.] using SSR markers” was undertaken at College of Agriculture, Vellayani, Thiruvananthapuram to assess the genetic variability among Stylosanthes accessions using SSR markers and to construct the population structure of Stylosanthes genotypes thereby delimiting these species. In this study, 19 accessions of Stylosanthes which belong to the genotypes S. scabra, S. seabrana, S. hamata and S. guianensis were collected from IGFRI, Jhansi, Kerala Livestock Development Board and centres under AICRP on Forage Crops and Utilisation. The 19 accessions were characterized using fifty seven molecular markers and correlated with the available phenotypic data. The purity and concentration of DNA ranged from 1.63 to 1.96 and 525 ng/µl to 3024 ng/µl respectively, indicates that a good quality DNA obtained from the Stylosanthes species. Forty nine markers showed amplification and produced a total of 120 alleles among the 19 Stylosanthes accessions. Forty one showed polymorphic bands and they produced a total of 101 polymorphic alleles. The highest number of alleles was produced by gSsb-16 (6 alleles) and the polymorphism information content (PIC) for these markers revealed that gSsb-11, eSgu-29 and eScap-24 (0.48) have the highest PIC followed by gSsb-16 (0.477). S. hamata (T5) and S. seabrana (T18) showed more than one allelic band in a maximum number while S. seabrana Phule Kranti (T9) showed only one allelic band with the entire set of polymorphic markers A Bayesian model population structure study of these 19 Stylosanthes accessions using STRUCTURE v2.3.4 showed the existence of three gene pools (number of sub-population, k = 3). Also, the dendrogram generated using NTSYSpc v2.02e, based on 41 markers distinctively demarcated Stylosanthes accessions into five clusters indicating its vast genetic diversity in the 91 population. A maximum genetic similarity of 85.37% was shown by two pairs of accessions namely S. scabra ILCA140 (T1) with S. seabrana (T19) and S. scabra Fitzroy (T7) with S. seabrana (T13). A minimum genetic similarity of 48.78% was shown by S. guianensis CIAT (T10) with S. hamata (T11). Variance components analysis of seven phenotypic characteristics showed that the values of PCV and GCV was higher for leaf breadth, green fodder yield per plot and dry fodder yield per plot; high heritability coupled with high genetic advance was noted for green fodder yield per plot and dry fodder yield per plot. Cluster analysis based on phenotypic data divided the 19 Stylosanthes accessions into five clusters. The highest similarity was observed in S. scabra DRSS4-RRR94197 (T4) with S. seabrana (T14) at a similarity coefficient of 0.71. In the study, S. scabra with S. seabrana showed the highest genetic similarity within the genotypes in terms of molecular and phenotypic cluster analysis and the grouping was performed irrespective of the origin of genotypes. A better performance in phenotypic traits and molecular analysis was noticed in S. guianensis Reyan (T8) and S. guianensis CIAT (T10) showing their suitability in fodder improvement programmes of Stylosanthes species. Overall, the level of genetic variability and 76.9 per cent average polymorphism indicated by the primers in the current study suggests that SSR markers can be utilized for fodder improvement and genetic resource management and utilization. For proper validation of the results obtained, cytological studies of the Stylosanthes accessions, increasing the number of accessions in the different species and evaluation of more SSR markers need to be done.
Standardisation of in vitro propogation techniques in thathiri (Woodfordia fruticosa (L.) Kurz.)
(Department of Plant Breeding and Genetics, College of Horticulture,Vellanikkara, 2005) Gayathri, G; Arya, K
Variability assessment of fodder cowpea (vigna unguiculata (L.) walp) for mosaic resistance using SSR markers
(Department of Genetics and Plant Breeding, College of Agriculture,Vellayani, 2025) Kavya Suresh, S S.; Gayathri, G
The study entitled “Cultivation of Trametes spp. and assessment for laccase activity and cytotoxicity” was conducted at Department of Plant Pathology, College of Agriculture, Vellayani during 2023-2025 with the objectives of standardization of cultivation of Trametes spp. for laccase activity, polysaccharide production and assessment of its cytotoxicity. Survey was conducted at different locations of Thiruvananthapuram, Kollam and Pathanamthitta districts (AEU-1 and 2) for the collection of native Trametes sp. and five mushrooms were obtained viz, M1. M2, M3, M4 and M5. These native mushrooms were isolated and made into pure culture. Cultural characterization of all the isolates (I1. I2, I3, I4 and I5) was carried out using Potato Dextrose Agar (PDA) and observations on mycelial characters, growth rate, and time taken for complete growth in Petri dish (9 cm) were made. Among the isolates I4 was found to be best in terms of the mycelial characters and growth. The molecular characterization was conducted using LSU primers and confirmed the identity of I4 as Trametes sp. (PVO12560). This isolate was selected and compared with Trametes versicolor (DMRO-211). The physiological studies to identify the best media was carried out with I4 and T. versicolor on five different media viz., Potato dextrose agar (PDA), Malt extract agar (MEA), Peptone potato dextrose agar (PPDA), Potato malt agar (PMA) and Czapek Dox agar (CDA). MEA medium recorded the highest mycelial growth rate (1.80 cm day-1) and minimum of 5 days for complete growth in Petri dish for both the isolates. This was followed by PPDA and PMA in I4 and T. versicolor respectively. The optimum temperature for the growth of both the isolates were evaluated at range of 15°C to 35°C in MEA medium. Both the isolates showed optimal growth at 30°C. Higher and lower temperatures (35ºC and 15ºC) were inhibitory for the mycelial growth of I4 while growth was observed in T. versicolor at 15 and 35º C. The cultures of both isolates exhibited rapid growth when incubated at 30ºC. The optimal pH was assessed using MEA medium adjusted to a pH range of 4.5 to 8.0. Isolate I4 demonstrated the highest growth within the pH range of 5.5 to 6.5, whereas T. versicolor showed optimal growth between pH 5.5 and 6.0. Both isolates exhibited growth reduction at pH levels below 5 and above 7. 93 Four different substrates viz., paddy grains, wheat grains, sorghum grains and sawdust (supplemented with 10% rice husk) were evaluated as spawn substrates for the growth and colonization of I4 and T. versicolor. Sorghum grains were observed to be the most suitable substrate, with short spawn run period of 10 days for I4 and 9.75 days for T. versicolor. Substrates suited for sporocarp production of I4 and T. versicolor was evaluated using different media viz., paddy straw, sawdust (amended with 10% rice bran and wheat bran 10%), sawdust + paddy straw (2:3), and spent mushroom substrate. Among these, sawdust amended with 10% rice bran was found to be the efficient substrate for both species. I4 completed spawn run in 38 days and produced 42.7 g of sporocarps, while T. versicolor took 39.5 days for spawn run and yielded 29.5 g. Sawdust supplemented with wheat bran resulted in significantly lower yield. The substrates paddy straw and spent mushroom substrate failed to produce any sporocarp attributed to heavy contamination and poor mycelial colonization. Polysaccharide content was estimated from dried fruiting bodies, where I4 yielded 62.1 % and T. versicolor yielded 56.9 %. GC-MS analysis of mushroom extracts revealed diverse bioactive compounds in both species, including polysaccharides, fatty acids, phenols, and organic compounds. Of these several compound beta D glucopyranose and 1,3,5, cyclohexanetetrol has been reported to possess anticancerous, antioxidant and antimicrobial properties. The isolate I4 exhibited the highest laccase activity during the mycelial stage (64.197 U ml⁻¹), followed by pin head formation stage (52.957 U ml⁻¹) and young fruiting body stage (45.980 U ml⁻¹). T. versicolor exhibited the highest laccase activity at the pin head formation stage (55.863 U ml⁻¹) followed by young fruiting body stage (46.420 U ml⁻¹,) and mycelial stage (41.720 U ml⁻¹). The cytotoxic activity of both isolates was determined using the MTT assay against human colon cancer (HCT-116) cell lines. The ethanolic extract of I4 demonstrated an IC50 value of 371.85 μg mL⁻¹, while T. versicolor showed slightly higher cytotoxicity (308.44 μg mL⁻¹). The present study concluded occurrence