PhD Thesis

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Subject: search.filters.subject.Plant breeding and genetics

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Now showing 1 - 6 of 6
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    Introgression of TY-2 gene for resistance to tomato leaf curl virus(ToLCV) into tomato variety anagha through marker assisted backcross
    (Department of plant breeding and genetics, college of agriculture, Vellayani, 2023-09-16) Bhaskar Reddy, S; Beena Thomas
    The present research work entitled ‘Introgression of Ty-2 gene for resistance to Tomato leaf curl virus (ToLCV) into tomato variety Anagha through marker assisted backcross’ was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during the year 2019-2023, with an objective to develop high yielding and ToLCV resistant backcross progenies by introgression of Ty2 gene into tomato variety Anagha through marker assisted backcross and also to understand the nature and magnitude of gene effects of different yield related characters. The 17 BC2F1 lines containing Ty2 gene developed in the study can be carried forward for the development of a ToLCV resistant essentially derived variety (EDV). Pyramiding of resistance genes Ty-1, Ty-3, Ty-4, ty-5 or Ty-6 along with Ty2 may enhance the spectrum and durability of resistance. In generation mean analysis, additive and additive x additive gene effects are significant for attributes investigated. Non-additive gene effects were observed to be overpower additive gene effects. Hence, breeding procedure which could exploit non-additive gene action would be suitable for improvement. These methods are used for improvement followed by conventional selection.
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    Introgression of TY-2 gene for resistance to tomato leaf curl virus(ToLCV) into tomato variety anagha through marker assisted backcross
    (Department of plant breeding and genetics, college of agriculture, Vellayani, 2023-09-16) Bhaskar Reddy, S.; Beena Thomas
    The present research work entitled ‘Introgression of Ty-2 gene for resistance to Tomato leaf curl virus (ToLCV) into tomato variety Anagha through marker assisted backcross’ was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during the year 2019-2023, with an objective to develop high yielding and ToLCV resistant backcross progenies by introgression of Ty2 gene into tomato variety Anagha through marker assisted backcross and also to understand the nature and magnitude of gene effects of different yield related characters. The 17 BC2F1 lines containing Ty2 gene developed in the study can be carried forward for the development of a ToLCV resistant essentially derived variety (EDV). Pyramiding of resistance genes Ty-1, Ty-3, Ty-4, ty-5 or Ty-6 along with Ty2 may enhance the spectrum and durability of resistance. In generation mean analysis, additive and additive x additive gene effects are significant for attributes investigated. Non-additive gene effects were observed to be overpower additive gene effects. Hence, breeding procedure which could exploit non-additive gene action would be suitable for improvement. These methods are used for improvement followed by conventional selection.
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    Introgression of Saltol gene into rice variety Sreyas
    (Department of Plant Breeding and Genetics, College of Agriculture,Vellayani, 2023) Anju Mariam Joseph; Arya, K
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    Genetic diversity analysis for nutrient efficiency and identification of nutrient responsive genes in cassava (Manihot esculenta Crantz)
    (Department of Plant Breeding and Genetics, College of Agriculture,Vellayani, 2023) Swathy Sivan; Arya, K
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    Induction and evaluation of genetic variability in chethikoduveli
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Arya, K; Gopimony, R
    The present study "Induction and evaluation of genetic variability in Chethikoduveli (Plumbago rosea L.) was undertaken in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1995-1998. The study was undertaken through the conduct of two experiments. (i) Germplasm collection and evaluation (ii) induction of variability. Two noded semi-hardwood cuttings of seven ecotypes of Plumbago rosea and one related species, Plumbago zeylanica were used for the first experiment. The ecotype of P. rosea from College of Horticulture, Vellanikkara was used for the second experiment. The cuttings were treated with six doses of gamma rays (0.25, 0.50, 0.75, 1.00, 1.25 and 1.50 kR) and M I V I generation was evaluated. Pollen germination was not noticed in P. rosea whereas the pollen grams of P. zeylanica germinated. The germination of seeds was more quickly in scarified seeds of P. zeylanica than seeds with intact seed coat. All the pollination techniques failed to give any positive result on seed set in P. rosea. Normal pairing of chromosomes were observed in meiotic cells of both the species. All characters studied had significantly high genotypic correlation with yield. High estimates of heritability (broad sense) was observed for all characters studied. High estimates of heritability coupled with high genetic advance was observed for plant height and root length which indicate that direct selection for improvement of these traits will be effective. Path coefficient analysis showed that dry root yield had maximum direct effect on plumbagin content of roots and plant height had maximum direct effect on fresh and dry root yield. The index score for selection was highest for P zeylanica followed by the ecotype of P rosea from Kottayam. EDso of gamma rays for the stem cuttings of P rosea was 1.685 kR. The sprouting percentage of cuttings was significantly decreased with increased doses of mutagen. Progressive delay in sprouting was noticed as the level of dose increased. The percentage lethality was higher in mutagen treated population than in the control. The optimum dose for inducing maximum yield and yield attributing characters ranged between 0.70 kR and 0.85 kR of gamma rays. High yielding mutants were observed in plants treated with 1.0 kR of gamma rays. The highest values for yield and yield attributing characters were obtained for 0.75 and 1.00 kR gamma rays. Gamma rays at 1.0 kR was most effective in inducing variability for root yield.
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    Standardisation of in vitro techniques for rooting,hardening and micrografting in cocoa (Theobroma cacao L.)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Bindu, M R; Mallika, V K