1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Identification of superior genotypes for yield and quality in red gram[Cajanas cajan (L.)Millsp.] suitable for Kerala(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2026-01-05) Shirsat Mahesh Santosh; Beena ThomasRed gram [Cajanus cajan (L.) Millsp.], commonly known as pigeonpea, is an important tropical and subtropical legume valued for its edible seeds. It serves as both a green vegetable and a split pulse (‘dhal’), being a rich source of protein, carbohydrates, vitamins, minerals, and essential amino acids such as lysine, methionine, and tryptophan. In combination with cereals, pigeonpea provides a nutritionally balanced diet and contributes to food security and sustainable smallholder farming systems. India is the largest producer of pigeonpea. It ranks second among pulses after chickpea, with major cultivation in Maharashtra, Karnataka, Madhya Pradesh, Uttar Pradesh, and Gujarat. In Kerala, however, despite being an integral part of the diet, commercial cultivation of pigeonpea is meagre. Therefore, the present research entitled “Identification of superior genotypes for yield and quality in red gram [Cajanus cajan (L.) Millsp.] suitable for Kerala” was undertaken in the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, during 2021-2025. In the first experiment, thirty genotypes originating from ICRISAT (Hyderabad), TNAU (Coimbatore), and IARI (New Delhi) were collected and evaluated in the field to study variability parameters and genetic divergence (D2). Analysis of variance revealed highly significant differences among genotypes for all 16 traits studied, indicating substantial genetic variability. The genotypic and phenotypic coefficients of variation (GCV and PCV) exhibited high values for traits such as the number of primary branches per plant, number of pods per plant, seed yield per plant, biological yield, and the content of total phenol, tannin, and methionine, indicating a strong potential for improvement through selection. High heritability coupled with high genetic advance as a percentage of the mean was observed for most traits, indicating the predominance of additive gene action, making direct selection effective. Correlation analysis revealed that seed yield per plant was positively and significantly associated with number of pods per plant, biological yield, harvest index, primary branches, and seeds per pod, while phenol content showed a significant negative correlation. Path analysis indicated that biological yield, flowering traits, and harvest index exerted strong positive direct effects on seed yield, whereas days to bud initiation and plant height contributed negatively. All thirty genotypes were assembled into six clusters using D² analysis. Cluster III had the highest number of genotypes (9), followed by cluster IV (5 genotypes), and clusters I, II, V, and VI each had one genotype. The highest intra-cluster distance was recorded in cluster IV and the lowest in cluster II, whereas the highest inter-cluster distance was observed between clusters I and VI, followed by clusters IV and V. Molecular diversity analysis among the 30 genotypes was conducted using 30 Simple Sequence Repeat (SSR) markers. Of these, 14 were polymorphic, 9 were monomorphic, and 7 markers failed to amplify. The Polymorphic Information Content (PIC) values of polymorphic SSR markers ranged from 0.12 (ASSR 363) to 0.50 (ASSR 281). The lowest Jaccard’s similarity coefficient was observed between genotypes ICPL 300 and ICPL 22081 (0.167). UPGMA cluster analysis grouped all 30 pigeonpea genotypes into six clusters, with Cluster I being the largest (12 genotypes), followed by Cluster III (11 genotypes), Cluster V (3 genotypes), Cluster IV (2 genotypes), and Clusters II and VI with one genotype each. Principal Coordinate Analysis (PCoA) confirmed the presence of considerable genetic diversity among the 30 red gram genotypes. Ten superior genotypes, viz., ICPL 11259, ICPL 11300, ICPL 11318, ICPL 11326, ICPL 20327, ICPL 22045, ICPL 22084, ICPL 22081, APK 1, and Pusa Arhar 16, were selected based on seed quality attributes and seed yield per plant. Phenological evaluation of these genotypes was conducted in the field for three seasons (Rabi, Summer, and Kharif). Seasonal evaluation revealed that seed yield per plant was highest during Kharif, though with high variability, whereas Rabi showed relatively stable but lower yields, and Summer provided balanced performance with moderate yield consistency. Among the ten genotypes, APK 1 and Pusa Arhar 16 consistently recorded high seed yield across all three seasons along with good quality traits and are suitable for cultivation in Kerala. Genotypes grouped in different clusters with maximum inter-cluster distances indicate high genetic diversity, which can be exploited in future breeding programmes to manifest heterosis and develop superior hybrids. Genotypes with high molecular diversity can serve as parental lines for making crosses with a broad genetic base, thereby enhancing the scope of genetic improvement.Item Morpho- molecular characterisation and hybridisation in Oncidium and equitant oncidium orchids(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2025-07-30) Aswini, M S; Beena ThomasThe present research programme entitled “Morpho-molecular characterisation and hybridisation in Oncidium and equitant Oncidium orchids” was carried out in the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2022-24. This research programme aimed to develop novel hybrids in Oncidium orchids as it is a less focused commercially important orchid species for crop improvement programmes. A total of twenty parental genotypes were collected from different nurseries across South India viz., Oncidium Jairak Fragrance (P1), Oncidium Jairak Fragrance OngKnot (P2), Oncidium J.F. Ha-Nu-Man (P3), Oncidium J.F. Pra-Lak(P4), Oncidium J.F. Montho (P5), Oncidium Guan Shin Rouge Ruby (P6), Oncidium Spacerace coco (P7), Brassia arcuigera (P8), Oncidium Sharry Baby (P9), Oncidium Yuan Nan Gold (P10), Oncidium Winterwonder white fairy (P11), Oncidium Kampangsan White (P12), Oncidium Golden Shower (P13), Oncidium Hybrid Miltasssia Sheloib Tolkein (P14), Oncidium Narisara SS (P15), Miltasia Royal Robe (P16), Oncidium Gum Pagan (P17), Oncidium Wild Cat 'Golden Red Star', Tolumnia Jairak Firm Sweet Pink (P19) and Tolumnia William Thurston (P20) were chosen for the research. They were subjected to evaluation for various qualitative and quantitative traits. Evaluation of parents was done for twenty-four quantitative traits. In addition, sixteen quality traits were also estimated in all the parental genotypes. In this study, for most of the traits, genotypic variance was observed close to the phenotypic variance, indicating that genetic factors predominantly control the variation in these traits. The PCV and GCV values were high for petal width, indicating substantial variability. Heritability was high (>60%) for nearly all traits, such as plant height, number of flowers per inflorescence, flower length, flower width, petal length, petal width, lip length, lip width, vase life and longevity of flowers in the stalk. Meanwhile, all the floral traits had high genetic advance as a percentage of the mean, indicating significant potential for improvement through selection, making them prime candidates for targeted breeding efforts. Overall, this analysis highlighted the strong potential for genetic enhancement of these traits in future breeding programs. In the correlation analysis, longevity of flowers in stalk or inflorescence exhibited a strong significant and positive correlation with vase life and length of inflorescence both at genotypic and phenotypic level. In the path analysis study, petal length stood out with the highest positive direct effect, making it the primary trait associated with enhancing the longevity of flowers. In this research programme, twenty parents were subjected to the molecular polymorphism study with the aid of twenty-five different ISSR (Inter Simple Sequence Repeat) markers. The ratio of absorbance at 260 nm and 280 nm (A260/A280) of all twenty extracted DNA samples of parents ranged between 1.80 and 2.03, indicating nearly 100% purity for the samples. The concentration of samples ranged between 445 and 1553 µg/ml. In this polymorphism study, UBC 844, UBC 824, UBC 807, UBC 818 and UBC 810 have shown higher PIC value. The percentage of polymorphic loci was found more for the primers UBC 807, UBC 808 and UBC 899 followed by UBC 810 and UBC 824. Further, hybridisation was carried out with the best ten genotypes selected based on flower synchronisation, flowering nature and variability studies. A total of seventy- three cross combinations were attempted based on flower synchronisation and flowering nature. P3, P4, P5, P8, P9, P10, P12, P16, P18 and P19 were the parents involved in the hybridisation process. Incompatibility reactions were noticed at different stages ranging from flower abscission before the onset of any visible post-pollination change to instances during the development of the capsule (seed pod). All the five cross- combinations obtained (P3 x P9, P10 x P5, P12 x P19, P19 x P5 and P5 x P19) were germinated successfully, sub-cultured at respective periods and planted successfully after the evaluation of plantlets. Oncidium species exhibit both self-incompatibility and interspecific pollination barriers, critical for maintaining genetic diversity and hybrid vigour. Following successful pollination, the developing capsule underwent several changes before harvest. Initially, the ovary showed slight enlargement and turned green. The longest capsule was obtained for the cross P10 x P5 (O. Yuan Nan Gold x Oncidium Jairak Fragrance Montho) and the shortest capsule was obtained for the cross P19 x P5 (Tolumnia Jairak Firm Sweet Pink x Oncidium Jairak Fragrance Montho). The cross combination P10 x P5 (O. Yuan Nan Gold x O. Jairak Fragrance Montho) recorded the highest days in this process and the lowest by P19 x P5. The total days required for green capsule harvest in successful crosses was minimum in the cross-combination P19 x P5. Orchid seeds are difficult to germinate naturally since it is devoid of natural storage organs for food reserves and the embryo is naked. In vitro germination using media like MS supplemented with benzylaminopurine (BAP) and Indoleacetic acid (IAA) has shown promising results. Out of five cross combinations in different bottles, all the combinations exhibited greening thereby initiating protocorm formation. In vitro propagation study revealed that the shortest time for initial germination was observed in P19 x P5 (Tolumnia Jairak Firm Sweet Pink x O. Jairak Fragrance Montho) (less than 1 month), while the longest is in P12 x P19 (1 month and 3 weeks). The fastest time for deflasking is also seen in P19 x P5 (O. Kampangsan White x Tolumnia Jairak Firm Sweet Pink) (7 months and 1 week), whereas the longest is in P12 x P19 and P5 x P19 (8 months and 1 week). This variation highlighted the influence of genetic combinations on growth stages in Oncidium orchid cross-combinations. Wide variation in days for different stages was noticed among different cross-combinations. The total days for initial germination ranged from 4 weeks to 1 month and 3 weeks. Further, days to protocorm formation varied from 1 month 4 weeks to 3 months and 1 week. The first leaf initiation started in 3 months and 2 weeks and ended up to 3 months and 4 weeks. Shoot initiation occurred from 4 months, 2 weeks of culturing to 5 months and 3 weeks of culturing. The roots were finally produced in 6 months to 6 months and 3 weeks. The deflasking was done for each cross-combination from 7 months, 1 week to 8 months, 1 week. Deflasked plantlets were subjected to morphological evaluation. Among the five cross combinations, P5 x P19 (Oncidium Jairak Fragrance Montho x Tolumnia Jairak Firm Sweet Pink) was observed as the longest plantlet for leaf length, root length, a greater number of roots and a higher root diameter. This indicated robust growth in seedling height, potentially due to favourable genetic combinations. The longest leaf reflected that superior leaf development is beneficial for photosynthesis and vigour. The longest root aids for better root extension, nutrient and water uptake. In conclusion, this research on Oncidium and equitant Oncidium orchids successfully integrated morpho-molecular characterisation, hybridisation and in vitro propagation to develop novel hybrids with significant genetic potential. Molecular diversity analysis using ISSR markers facilitated parental variability analysis, while hybridisation efforts yielded five promising cross-combinations, with P5 x P19 (Oncidium Jairak Fragrance Montho x Tolumnia Jairak Firm Sweet Pink) emerging as the most robust in terms of seedling vigour, leaf and root development and overall growth performance making it a promising candidate for further development. The study also optimised in vitro propagation protocols, ensuring successful germination and plantlet establishment. These findings underscore the potential of Oncidium orchids for commercial breeding, paving the way for further genetic enhancement and large-scale propagation.Item 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, GThe 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.Item 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, GThe 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 occurrenceItem Development of high yielding backcross inbred lines stacked with drought yield QTLs in rice (Oryza sativa L.)(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2025-01-13) Pooja Pavithran; Adheena Ram, AThe present study entitled “Development of high yielding backcross inbred lines stacked with drought yield QTLs in rice (Oryza sativa L.)” was carried out at the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2022-2024 with an objective to identify high yielding drought tolerant rice lines from BC₂F₃ lines of Manu Ratna stacked with drought yield QTLs. The BC₂F₃ population used in the study were derived from the cross between Manu Ratna and Improved White Ponni stacked with drought yield QTLs qDTY ₁.₁ and qDTY₁₂.₁ developed as a part of PhD project of this department. The field evaluation was conducted at Integrated Farming System Research Station, Karamana where BC₂F₃ lines were screened under water stress conditions. In the laboratory experiments, the selected BC₂F₃ lines were analysed for biochemical and physiological characteristics and the BC2F4 lines were further screened for drought stress tolerance using PEG 6000. One thousand fifty BC₂F₃ plants from 10 different families, along with parents Manu Ratna and Improved White Ponni, were raised in family block design with three replications for each family. Water was withheld for fourteen days to induce drought stress during panicle initiation stage. Biometric observations were recorded from 210 BC₂F₃ plants, selected based on early flowering, plant height, higher number of productive tillers and leaf rolling score. Analysis of variance showed significant differences between the families. Based on plant height, earliness of flowering, number of productive tillers and leaf rolling score, 20 plants were selected. Among these, MIB29-2-3-1, MIB-29-2-3-21, MIB-29-8-4-4, MIB-29-8-5-10, MIB-29-8-5-30, MIB-29-85-35 and MIB-84-3-3-4 showed superior performance for yield traits viz. number of productive tillers per plant, panicle length, number of spikelets per panicle, number of filled grains per panicle, grain yield per plant, 1000 grain weight, grain length and grain width. The selected 20 plants of BC₂F₃ generation were analysed for biochemical and physiological parameters viz relative water content, cell membrane stability index, total chlorophyll content, proline content and peroxidase activity. Analysis of variance showed significant differences among the selected lines for these biochemical and physiological parameters. Among the lines, MIB-29-8-5-35, MIB-29-2-3-1, MIB-84-3-3-4, MIB-119-5-7-33 and MIB-29-8-5-10 showed superior performance for all biochemical and physiological characters. Seeds from the selected superior 20 BC₂F₃ plants were further screened for drought stress tolerance at different PEG 6000 concentrations. The experiment was conducted using factorial completely randomized design with two factors and three replications. The main factor was 20 lines while the second factor was PEG concentrations with three levels (0, 10 and 15%). The observations on root length, shoot length and number of seeds germinated were observed. The computed parameters recorded include germination percentage, mean germination time, germination index, root shoot ratio, germination stress tolerance index, fresh weight stress tolerance index, dry weight stress tolerance index and seedling vigour index. The analysis of variance also showed a significant difference among the 20 lines for all the traits except mean germination time and root shoot ratio. Based on the mean performance of the lines under drought stress induced by PEG, MIB-29-2-3-1, MIB-29-8-5-35, MIB-43-5-3-66 and MIB-119-5-7-33 were found to have seedling stage drought stress tolerance. High PCV and GCV were observed for the characters such as root length, shoot length, root shot ratio, germination stress tolerance index, dry weight stress tolerance index and seedling vigour index. Mean germination time showed a high PCV and a moderate GCV. The characters such as number of seeds germinated, germination per cent and germination index showed a moderate PCV and GCV. The characters viz. root length, shoot length, germination stress tolerance index, fresh weight stress tolerance index, dry weight stress tolerance index and seedling vigour index showed a high heritability along with high genetic advance, which indicated that selection based on these traits would be effective. Correlation analysis identified a significant positive genotypic and phenotypic correlation between root length, shoot length and fresh weight stress tolerance index with seedling vigour index. Path analysis showed that shoot length had a positive high direct effect on seedling vigour index and a high indirect effect on seedling vigour index through root length.Among the selected lines, MIB-29-2-3-1 and MIB-29-8-5-35 had higher yield, superior performance for biochemical and physiological character under field study and better seedling stage growth traits under PEG induced drought stress. Hence, these lines can be advanced to further generations through pedigree method of breeding for developing high yielding drought tolerant varieties. These lines can also be further advanced through backcross to develop bold red kernel rice varieties.Item Phenotyping and marker assisted screening of rice (Oryza sativa L.) germplasm for sheath blight(Rhizoctonia solani kuhn) resistance(Department of Genetics and Plant Breeding, College of Agriculture,Vellayani, 2024-12-16) Bandela Chandana.; Adheena RamThe study entitled “Phenotyping and marker assisted screening of rice (Oryza sativa L.) germplasm for sheath blight (Rhizoctonia solani Kühn) resistance” was carried out at the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2022 to 2024 with an objective of artificial screening and identification of rice genotypes for sheath blight resistance and validation with molecular markers linked to reported QTLs of sheath blight resistance. The phenotypic screening for sheath blight resistance was conducted, using thirty rice genotypes and different biometric, biochemical and computed parameters were analysed. Analysis of variance revealed significant difference for all the biometric characters except number of tillers per plant. All the biochemical parameters such as peroxidise, catalase, polyphenol oxidase and phenylalanine ammonialyase showed an increase in biochemical activity in genotypes under stress but only phenylalanine ammonialyase showed significant difference among them. Studies on phenotypic coefficient of variation and genotypic coefficient of variation revealed high variation for lesion height, number of grains per panicle, number of unfilled grains per panicle and grain yield per plant. In general, PCV values were higher than GCV for all characters indicating the influence of environment towards total variance. High heritability with high genetic advance was noticed for days to heading, days to 50 per cent flowering, number of productive tillers per plant, stem thickness, panicle length, number of grains per panicle, thousand grain weight and grain yield per plant indicating the influence of additive gene action and suitability of these traits for selection. Panicle length, days to 50 per cent flowering, number of tillers per plant and thousand grain weight had significant positive correlation with grain yield per plant where as plant height and lesion height were negatively correlated with grain yield per plant. The days to 50 per cent flowering has a strong positive direct effect on grain yield per plant and days to heading through the days to 50 per cent flowering showed a strong indirect effect on grain yield per plant. Based on genetic divergence analysis 30 genotypes were grouped into four clusters. Cluster III with nine genotypes was the largest followed by cluster I (eight genotypes) and cluster IV (seven genotypes). The clusters II had the least number of genotypes (six). Based on the inter-cluster distances, clusters III and IV had the lowest divergence (6.50) while clusters I and IV recorded the highest divergence (11.41). The highest intra cluster distance was noticed among genotypes of cluster IV (6.32) and the lowest was noticed among genotypes of cluster II (5.36). The genotypes Remanika, Chenthadi, Krishnanjana, Panchami, Karishma, Revathy, White Ponni and Bhadra in the cluster I had the highest mean value for days to heading, days to 50 per cent flowering, number of tillers per plant, number of productive tillers per plant, stem thickness, panicle length, number of grains per panicle, thousand grain weight and grain yield per plant. Based on scoring of sheath blight severity and percentage disease index the genotypes Gouri, Chenthadi, Krishnanjana, Panchami, White ponni, VYT-1, Chenkayama and Onam were found to be resistant for sheath blight. Moderate resistance to sheath blight was shown by the cultivars Karishma, Revathy, Bhagya, VYT-7, Karuna, Sreyas, Prathyasa, Karthika, Chettivirippu, Makom, Uma and Bhadra. The 15 SSR markers linked to the reported sheath blight QTLs used for validation were polymorphic with the PIC value ranging between 0.17 (RM16200) and 0.63 (RM71). RM105 linked to qShB9-1 had the maximum number of alleles (4). The cluster analysis for marker data grouped the rice genotypes into two major clusters with cluster II having the highest number of genotypes. The high yielding rice genotypes Chenthadi and Krishnanjana were identified as resistant to sheath blight based on phenotypic and genotypic data. These genotypes can be used as donors for sheath blight resistance in future breeding programmes.Item Locating superior segregants with high yield and drought tolerance in yard long bean [Vigna unguiculata ssp. sesquipedalis (L.) Verdcourt](Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2024-10-22) Noru Raja Sekhar Reddy; Beena ThomasYard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt), a member of Fabaceae, holds a significant position among legume vegetable crops. Climate change induced drought can significantly impact its cultivation, yield, and production. Among abiotic stresses, drought is severe and affects the quality of the pods, reducing their size and nutritional content, ultimately leading to decreased growth and yield. This study was entitled “Locating superior segregants with high yield and drought tolerance in yard long bean (Vigna unguiculata ssp. sesquipedalis (L.) Verdcourt)”. The study was conducted in Department of Genetics and Plant Breeding at College of Agriculture, Vellayani, from 2022 to 2024. The research comprised of three main experiments: evaluation of F2 segregants in the field, a laboratory analysis of screening of F3 seeds for drought stress tolerance using PEG, and evaluation of F3 segregants in the field. The previous Ph.D. research work entitled “Gene action and gene expression analysis in yard long bean (Vigna unguiculata ssp. sesquipedalis (L). Verdcourt) for drought tolerance” done in the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani formed the materials of research work. The materials consisting of 200 seeds of yard long bean collected from F1 segregants from the cross of Katampally Local (Drought tolerant) ×Vellayani Jyothika (High yielding) were used for the present study. The collected 200 F2 segregants were evaluated for yield and various yield-related traits from September to December 2023. The seeds were sown at a spacing of 1.5 m х 0.45 m, and cultural operations were adopted as per the “Package of Practices Recommendations Crops 2016” of Kerala Agricultural University. From five superior segregants (F2-3, F2-79, F2-106, F2-130, and F2-184) the seeds were collected named as F3-1, F3-2, F3-3, F3-4, and F3-5. The collected seeds were used for laboratory experiment to assess drought tolerance by inducing osmotic stress in the laboratory. In the laboratory experiment, these five segregants were further assessed under drought stress conditions using two concentrations of PEG 6000 (-0.75 bar and -1 bar). Based 88 on germination percentage, root length, and seedling vigour index-I, F3-1 and F3-3 were identified as drought tolerant genotypes. The second field experiment (season - 2) involved the evaluation of the F3 segregants in a compact family block design with five progenies and five replications from February to May 2024. The seeds were sown at a spacing of 1.5 m х 0.45 m. The analysis of variance between families revealed that the mean sum of squares due to families was significantly different for all traits except pod width among all five families. The Bartlett’s test for homogeneity of error variances of five families indicated that error variances were homogenous for all characters except pod length, pods per plant, yield per plant, and crop duration. Genetic parameter analysis performed for five F3 families in traits like pod length, pod weight, pods per plant, yield per plant, and crop duration showed high phenotypic and genotypic variation, along with high heritability and genetic advance, indicating their suitability for selection. In the present investigation, the correlation studies indicated a significant positive correlation was shown by the characters like, pod weight, pods per plant, pod length, pod width, and harvest index with yield per plant. However, days to 50% flowering, crop duration, and vine length showed a significant negative correlation with yield per plant. Path analysis of the eight characters showing significant correlation with yield per plant revealed that the pod weight (1.09) and harvest index (1.03) exhibited a very high direct effect on yield per plant. The highest direct effect on yield per plant was shown by days to 50 % flowering (0.87) and pod width (0.79). A high indirect effect on yield per plant was shown by pod weight (3.32) through vine length. In conclusion, in field experiment (season-1) of evaluation of F2 segregants for yield and other related traits, genotypes F2-3, F2-79, F2-106, F2-130, and F2-184 were identified as superior for yield and other related traits out of 200 segregants. Genotypes F3-1 and F3-3 were identified as drought tolerant ones based on germination percentage, root length, and seedling vigour index-I in the laboratory experiment. In field experiment (season-2) of evaluation of F3 segregants for yield and other related traits, among five F3 families, F3-1 was identified as superior for yield and other related parameters. Within each family, superior progenies were progeny-1 (F3-1), progeny-1 89 (F3-2), progeny-2 (F3-3), progeny-3 (F3-4), and progeny-4 (F3-5). Based on the laboratory study, F3-1 was recognized as a superior segregant with drought tolerance. In field experiment, progenies from the F3-1 family showed high yield. These F3-1 segregants can be used in future breeding programmes for varietal development of yard long bean with high yield and drought tolerance.Item Genetic improvement through physical mutagenesis in Gladiolus grandiflorus L.(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2024-11-28) Aiswarya Raj, P T.; Beena ThomasThe present study entitled “Genetic improvement through physical mutagenesis in Gladiolus grandiflorus L.” was carried out in the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2022-24. This study aimed to develop novel ornamental characters in gladiolus through physical mutagenesis. The research programme involved two experiments. The first experiment was the determination of LD50 for gamma rays and the second was the induction of physical mutation through gamma irradiation in gladiolus. Corms of gladiolus varieties, Arka Amar and Arka Thilak were irradiated with gamma ray of doses 25, 40, 55 and 70 Gy using a gamma chamber with 60Co as the radiation source. Each dosage was applied to eight corms of both varieties. The survival rate of the plants decreased significantly with increasing radiation doses. The LD50 values were determined as 58.22 Gy for Arka Amar and 58.31 Gy for Arka Thilak through probit analysis. Based on the LD50 value, effective doses were fixed. Along with control, 45, 50, 55, 60 and 65 Gy were decided as treatments for both varieties. Corms of gladiolus varieties were then treated with effective doses of gamma radiation as estimated from the first experiment to induce physical mutagenesis. Six treatments of each varieties were evaluated in FCRD with three replications. The observations on quantitative characters and qualitative characters were recorded. All the characters exhibited significant differences among treatments. Most of the characters showed significant differences among varieties and in their interactions with treatments. The characters like number of leaves per plant, plant height, length and diameter of the floret, and rachis internodal length were the highest in Arka Thilak treated with 45 Gy. In Arka Amar, length of leaf blade and field life were the maximum at 45 Gy, and a greater number of florets per spike was observed at 50 Gy. Among the treatments, lower doses (45- 50 Gy) promoted better growth and development, whereas higher doses (60-65 Gy) had detrimental effects. 99 Among the varieties, Arka Amar exhibited variations in the predominant flower colour, resulting in the production of novel colour mutants at higher doses of gamma radiation. Corms treated with 50 Gy produced a dark pink flower with white colour in the central portion. Also, corms treated with 55 Gy showed a pink colour with light yellow shade in the central portion and a dark pink colour flower with golden yellow shade in central portion was observed in 60 Gy and 65 Gy treatments. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for the number of spikes per plant, number of cormels per corm, number of florets per spike, days to sprouting, plant height and number of leaves per plant. Low PCV and GCV were recorded in days to spike initiation and field life. High heritability along with high genetic advance was observed in days to sprouting, number of leaves per plant, length of leaf blade, width of leaf blade, plant height, days to full emergence of spike, spike length, length of the floret, diameter of the floret, number of florets per spike, rachis internodal length, corm weight and number of cormels per corm. This indicates that additive gene action plays a significant role in the expression of these traits. Hence, selection for these traits would be effective. The correlation studies showed a significant positive correlation for spike length with number of florets per spike, length of floret, diameter of floret, plant height, number of leaves per plant, length of leaf blade, corm weight, field life and rachis internodal length. However, days to sprouting and days to spike initiation showed a significant negative correlation with spike length. Path analysis revealed that the length of the floret and number of florets per spike exhibited the highest direct effect on spike length. A high indirect effect on spike length was shown by diameter of the floret through length of the floret. In conclusion, novel colour mutants were obtained in Arka Amar, and also ornamental traits such as length and diameter of the floret, number of spikes per plant, spike length, rachis internodal length, field life, and number of florets per spike were improved with novel variations through gamma irradiation. Lower doses, such as 45 Gy and 50 Gy, were found to be more effective for the development of novel ornamental traits in gladiolus. 100 These treatments can be used in future breeding programmes to improve economically important floral traits. The best treatment combination obtained in this study was Arka Amar with 50 Gy as it produced novel colour mutants along with more number of flowers and more number of spikes per plant. These colour mutants can be multiplied through in vitro techniques.Item Development of high yielding phyllody tolerant varieties in sesame (Sesamum indicum L.)(Department of Genetics and Plant Breeding, College of Agriculture,Vellayani, 2024-02-12) Shrithar Bhalaji, B K; Lovely, BA research programme was carried at the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during the period 2021-2023 with the objective of developing high yielding varieties of sesame with tolerance to sesame phyllody and enhanced oil content . The best performing lines identified during the previous study entitled “Potential of Sesame (Sesame indicum L.,) genotypes with respect to yield and phyllody tolerance in Onattukara Region” were used as female lines and the varieties which showed phyllody tolerance were used as male tester parents for studying the combining ability and heterosis by adopting line x tester mating design to elucidate the gene action and identify the superiorly performing crosses. The hybrids produced were subjected to hybridity confirmation using 30 polymorphic SSR molecular markers which are having more than 80% PIC values. The produced twelve F1 along with its parents were evaluated for the biometric parameters including days to first flowering , days to fifty percent flowering, number of capsules per plant, capsule length, plant height, number of primary branches, seed yield per plant, number of seeds per capsule, dry pod weight, 1000 seed weight, days to maturity, seed yield per plant and biochemical parameters for phyllody tolerance including enzyme activities of peroxidase and polyphenol oxidase using experimental design randomised block design. Phyllody tolerance was phenotypically scored and the disease intensity and vulnerability index were also estimated to identify the tolerant crosses. Statistical analysis including Anova for line x tester mating design with parents and heterosis was performed using TNAUSTAT software. Significant positive GCA effects observed for capsules per plant in parent Ayali 1, capsule length in Thilathara, Ayali 1, 1000 seed weight in Thilak, seed yield per plant in Ayali 1, PO activity in Thilathara, Thilarani, Ayali 5, PPO activity in Thilathara, Kayamkulam 1 and Ayali 5. Significant specific combining ability was also observed for some characters. Significant positive heterosis was observed for the character number of primary branches in cross Thilarani x Ayali 1, capsules per plant in Thilarani x Ayali 1, capsules per plant in Thilarani x Ayali 5 and Kayamkulam 1 x Ayali 2, oil content in Thilak x Ayali 1, PO activity in Thilathara x Ayali1, Thilathara x Ayali 5, Thilarani x Ayali 2, Thilarani x Ayali 5, Thilak x Ayali 1, Thilak x Ayali 2, Kayamkulam 1 x Ayali 1, Kayamkulam 1 x Ayali 5.Item Identification of maker-trait associations for yield and drought tolerance in greengram (Vigna radiata) using SSR markers(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2025-01-03) Amritha, K Binukumar.; Lovely, BThe study entitled “Identification of marker-trait associations for yield and drought tolerance in greengram (Vigna radiata) using SSR Markers” was conducted at the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2022-2024 with an objective of assessing genetic diversity among greengram accessions for yield and drought tolerance using SSR markers to identify superior climate resilient genotypes. The research programme encompassed of three experiments. In the first experiment, drought tolerance of 50 greengram genotypes was evaluated under laboratory and pot conditions using polyethylene glycol (PEG) 6000 treatments and controlled water stress. Morpho-physiological and biochemical traits were assessed, revealing significant differences in drought tolerance indicators among the genotypes. High heritability and genetic advance were observed for all the characters studied except seedling shoot length, root-shoot ratio and total chlorophyll. Correlation and path analysis revealed strong positive relationship between root traits and proline content, emphasizing its importance in drought tolerance. The genotypes were categorized based on germination drought tolerance index and root length drought tolerant index values as highly susceptible, susceptible, moderately susceptible, moderately tolerant and tolerant. Andhra local, ML 1415, Co 8, C4 PDM 139 and VBN 5 emerged as promising candidates for drought tolerance based on both the drought tolerance indices. In Experiment II, a field trial was conducted from June to September 2024 to evaluate yield-related traits in 40 selected genotypes, using Randomized Block Design (RBD) in three replications. The genotypes were evaluated for various biometric and biochemical traits and significant differences were observed for all the traits. The study found high heritability coupled with high genetic advance for traits such as the number of primary branches, plant height, number of pods per plant, individual pod weight, hundred seed weight and seed yield per plant, highlighting the strong potential of these genotypes for yield improvement. A significant positive correlation was shown by number of pods 178 per plant, number of seeds per pod, pod length, individual pod weight and hundred seed weight with seed yield per plant. Path coefficient analysis also revealed that the number of pods per plant had the highest direct effect on seed yield per plant followed by pod length, individual pod weight and hundred seed weight. The genetic divergence analysis grouped the 40 genotypes into six clusters based on biometric and biochemical traits indicating high diversity between the clusters. Cluster I, with 17 genotypes was the highest and included the identified drought-tolerant genotypes, while Clusters II, with 15 genotypes and cluster V, with 3 genotypes were characterized by high-yielding genotypes. Discriminant function analysis further validated the selection, and based on the selection index value the genotypes IPM 2057, Kozhikode local, Kayamkulam local, Co GG 912 and EC 398884 were identified as high yielding superior genotypes. In Experiment III, SSR markers were used to genotype 50 greengram accessions, with seven of ten markers revealing polymorphism. Out of the 10 markers, CEDG 014 produced highest percentage of polymorphism information content (PIC) value, while CEDG 008 produced the lowest. The Jaccard's similarity coefficient was computed utilizing the DNA banding patterns derived from the selected greengram genotypes and polymorphic SSR markers. The greengram genotypes were categorized into two distinct clusters based on their genotypic data: cluster one comprised of single genotype, cluster two included majority genotypes. The cluster 2 was again divided into 2 sub-clusters, in which the sub-cluster 2 comprises the identified drought tolerant and superior high yielding greengram genotypes. The study revealed, the genotypes, Andhra local, Co 8, ML 1415, C4 PDM 139 and VBN 5 as drought tolerant superior genotypes while, IPM 2057, Kozhikode local, Kayamkulam local, Co GG 912 and EC 398884 as high yielding superior genotypes. The genotypes Kozhikode local and Kayamkulam local were found to be moderately tolerant to drought and high yielding. The clustering of the genotypes using SSR markers also grouped them into a single cluster. The superior genotypes identified can be 179 recommended for future hybridization programmes as parents to develop a variety with high yield and drought tolerance in greengram.The research programme encompassed of three experiments. In the first experiment, drought tolerance of 50 greengram genotypes was evaluated under laboratory and pot conditions using polyethylene glycol (PEG) 6000 treatments and controlled water stress. Morpho-physiological and biochemical traits were assessed, revealing significant differences in drought tolerance indicators among the genotypes. High heritability and genetic advance were observed for all the characters studied except seedling shoot length, root-shoot ratio and total chlorophyll. Correlation and path analysis revealed strong positive relationship between root traits and proline content, emphasizing its importance in drought tolerance. The genotypes were categorized based on germination drought tolerance index and root length drought tolerant index values as highly susceptible, susceptible, moderately susceptible, moderately tolerant and tolerant. Andhra local, ML 1415, Co 8, C4 PDM 139 and VBN 5 emerged as promising candidates for drought tolerance based on both the drought tolerance indices. In Experiment II, a field trial was conducted from June to September 2024 to evaluate yield-related traits in 40 selected genotypes, using Randomized Block Design (RBD) in three replications. The genotypes were evaluated for various biometric and biochemical traits and significant differences were observed for all the traits. The study found high heritability coupled with high genetic advance for traits such as the number of primary branches, plant height, number of pods per plant, individual pod weight, hundred seed weight and seed yield per plant, highlighting the strong potential of these genotypes for yield improvement. A significant positive correlation was shown by number of pods 178 per plant, number of seeds per pod, pod length, individual pod weight and hundred seed weight with seed yield per plant. Path coefficient analysis also revealed that the number of pods per plant had the highest direct effect on seed yield per plant followed by pod length, individual pod weight and hundred seed weight. The genetic divergence analysis grouped the 40 genotypes into six clusters based on biometric and biochemical traits indicating high diversity between the clusters. Cluster I, with 17 genotypes was the highest and included the identified drought-tolerant genotypes, while Clusters II, with 15 genotypes and cluster V, with 3 genotypes were characterized by high-yielding genotypes. Discriminant function analysis further validated the selection, and based on the selection index value the genotypes IPM 2057, Kozhikode local, Kayamkulam local, Co GG 912 and EC 398884 were identified as high yielding superior genotypes. In Experiment III, SSR markers were used to genotype 50 greengram accessions, with seven of ten markers revealing polymorphism. Out of the 10 markers, CEDG 014 produced highest percentage of polymorphism information content (PIC) value, while CEDG 008 produced the lowest. The Jaccard's similarity coefficient was computed utilizing the DNA banding patterns derived from the selected greengram genotypes and polymorphic SSR markers. The greengram genotypes were categorized into two distinct clusters based on their genotypic data: cluster one comprised of single genotype, cluster two included majority genotypes. The cluster 2 was again divided into 2 sub-clusters, in which the sub-cluster 2 comprises the identified drought tolerant and superior high yielding greengram genotypes. The study revealed, the genotypes, Andhra local, Co 8, ML 1415, C4 PDM 139 and VBN 5 as drought tolerant superior genotypes while, IPM 2057, Kozhikode local, Kayamkulam local, Co GG 912 and EC 398884 as high yielding superior genotypes. The genotypes Kozhikode local and Kayamkulam local were found to be moderately tolerant to drought and high yielding. The clustering of the genotypes using SSR markers also grouped them into a single cluster. The superior genotypes identified can be 179 recommended for future hybridization programmes as parents to develop a variety with high yield and drought tolerance in greengram.