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

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    Identification of superior tomato (Solanum lycopersicum L.) hybrids with high yield under water stress
    (Department of genetics and plant breeding, college of agriculture, Vellayani, 2023-11-14) Harisha, K.; Beena Thomas
    The present study, entitled “Identification of superior tomato (Solanum lycopersicum L.) hybrids with high yield under water stress” was conducted in the Department of Genetics and Plant Breeding, College of Agriculture, Vellayani during 2021–2023 with the objective of screening of tomato (Solanum lycopersicum L.) hybrids for high yield under water stress condition. The materials for research were chosen from a previous project in the Department of Genetics and Plant Breeding. The experimental material included ten F1 hybrids, viz., Vellayani Vijay x Palakkad local, PKM-1 x Kuttichal local, PKM-1 x Palakkad local, PKM-1 x Kottayam local, Akshaya x Kuttichal local, Akshaya x Palakkad local, Akshaya x Kottayam local, Arka Meghali x Kuttichal local, Arka Meghali x Palakkad local and Arka Meghali x Kottayam local. These hybrids were evaluated in both field and pots to identify the F1 hybrid combination with superior performance for yield under water stress condition. The field experiment was laid out in a randomized block design (RBD) with ten treatments and three replications, and the pot experiment was conducted in a completely randomized design (CRD) with ten treatments and three replications. Water stress was imposed by restricting irrigation once in three days from the flowering stage onwards in both field and pot experiments. The analysis of variance was carried out for the characters under study, viz., plant height (cm), number of primary branches per plant, number of days to 50% flowering, number of flower cluster per plant, number of fruits per cluster, number of fruits per plant, fruit weight (g), yield per plant (g), relative water content, membrane stability index, total soluble solids (0Brix) and total acidity in both field and pot experiments. A significant difference was noticed for all the characters of F1 hybrids in both field and pot experiments. The mean performance of the F1 hybrids for the characters under study was recorded. The highest yield per plant was shown by Akshaya x Palakkad local, which also showed the maximum value for other characters like flower cluster per plant, fruits per cluster and fruits per plant in both field and pot experiments under water stress condition. The F1 hybrid Arka Meghali x Kottayam local showed the minimum value for most of the characters in both field and pot experiments under water stress condition, hence it is noted as drought susceptible. Qualitative analysis was carried out for F1 hybrids. The Maximum total soluble solids was observed for PKM-1 x Palakkad local, and the maximum total acidity was shown by Arka Meghali x Kottayam local in the field under water stress condition. In the pot experiment, the maximum total soluble solids was recorded by Akshaya x Palakkad local, and the highest total acidity was recorded by PKM-1 x Kottayam local. Analysis of physiological traits showed that the F1 hybrid, Akshaya x Palakkad local recorded the highest relative water content and membrane stability index in both field and pot experiments under water stress condition, indicating that this F1 hybrid is tolerant to electrolyte loss under water stress condition. Genetic parameters were also estimated for all the characters under study. The highest PCV and GCV were shown by yield per plant, primary branches per plant, total acidity, and flower cluster per plant in the field experiment. The characters fruits per cluster and total acidity showed the maximum PCV and GCV in the pot experiment. Under both field and pot conditions, high heritability with high genetic advance was observed for yield per plant, flower cluster per plant, fruits per plant, fruits per cluster and fruit weight. Correlation and path analysis were also performed for the selected traits. All characters showed a significant positive correlation with yield per plant, except days to 50% flowering and membrane stability index, which showed a negative association with the yield per plant in the field experiment. In pot studies, all characters showed a positive association with yield per plant except membrane stability index, which showed a negative association with the yield per plant. The characters plant height, flower cluster per plant and fruits per plant showed a significant positive direct effects on yield per plant in both field and pot experiments. The present study revealed that the F1 hybrid Akshaya x Palakkad local showed superior performance for most of the characters in both field and pot experiments under water stress condition. Hence, this F1 hybrid is considered as water stress tolerant and can be utilized in further crop improvement programs.
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    Studies on induced mutations in rice (Oryza sativa L.)
    (Division of genetics and plant breeding ,Agricultural college and research institute , Coimbatore., 1971) Gopinathan Nair, V
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    Legume pod borer resistance and genetic divergence in domestic germplasm of yard-long bean (Vigna unguiculata ssp. sesquipedalis(L.) Verdc.)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2000) Vidya, C; Sunny K Oommen
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    Identification of stable male sterile lines and better combiners for exploitation of hybrid vigour in rice (Oryza Sativa L.)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Rosamma, C A; Vijayakumar, N K
    Investigations to identify stable male sterile lines and better combiners for the exploitation of hybrid vigour in rice were conducted at College of Horticulture, Vetlantkkara and at Agricultural Research Station, Mannuthy during 1994-98. The study included evaluation of cytoplasmic - genic male sterile (CMS) lines to identify stable lines, identification of maintainers and restorers for different CMS lines, inheritance of fertility restoration, studies on the genetic distance between maintainers and restorers and genetic analysis of the hybrids. Out of the ten CMS lines evaluated, seven were identified as stable for pollen and spikelet sterility behaviour. Studies on the floral traits which influence outcrossing expressed variation between CMS lines and between seasons. Jyothi, Aruna, Pavizham and Ptb 10 produced more number of sterile hybrids when crossed with CMS lines having WA cytoplasm and hence these varieties can be used as maintainers. More number of fertile hybrid combinations were produced by Annapoorna, Matta Triveni, Kanchana, IR 36 and Aiswarya indicating the use of these varieties as restorers for WA cytoplasmic source. All the genotypes under study produced sterile hybrids when crossed with CMS lines having O. perennis cytoplasm and no restorers could be identified for this new source of cytoplasmic male sterility. Inheritance studies on fertility restoration indicated polygenic mode of inheritance for this particular character. Forty four rice genotypes included in the hybrid rice breeding programme were grouped into nine clusters, each having different number of genotypes. Maintainers and restorers were distributed in different clusters and no direct relation could be established between heterosis and genetic distance of the parents. Genetic analysis of the 34 fertile hybrids resulted in the identification of five hybrids having significant positive standard heterosis. Among the male sterile lines IR 68890A was identified as the best combiner for most of the agronomic traits and IR 68890A/Aiswarya was the best specific hybrid combination. Magnitude of the gca variance was more than the variance due to sca for days to flowering, total duration, harvest index, 100 seed weight and other grain characters indicating predominance of additive variance for these characters. Variance due to sca was more for plant height, tillers per plant, total dry matter production, grain yield per plant, straw yield per plant, panicle length and filled grains per panicle indicating predornlnance of variance due to dominance and epistasis. Studies on association of characters in hybrids revealed that total drymatter accumulation, harvest index, number of filled grains per panicle, grain breadth, panicle weight, grain density, flag leaf area and leaf area index at 60 days after sowing were positively correlated with grain yield produced by the hybrids. Negative influence of sterile cytoplasm was identified for most of the agronomic attributes.