PG Thesis

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

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    Combination breeding for high protein cowpea (Vigna unguiculata L. Walp)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Sarath, P S; Jiji Joseph
    Cowpea (Vigna unguiculata L. Walp) is one of the most important legume crops grown in India. It is a versatile pulse crop owing to its nutritional value, weed smothering nature, drought tolerant characters, soil restoring properties and multi-purpose uses. Protein deficiency has been reported to be one of the main nutritional problems in the developing world. About one billion people are reported to be suffering from protein deficiency and malnutrition worldwide. Studies have revealed that protein content in cowpea grain ranges between 18 to 40 per cent depending on the genotypes. Identifying high yielding varieties of cowpea with high protein content will not only contribute to food security and alleviate poverty but could also contribute to the alleviation of protein deficiencies. Review on the earlier research pointed to poor emphasis on the genetic improvement of cowpea for improved protein content. Hence, the present study was envisaged to combine the high protein trait with high yielding genotypes. The study was grouped under three experiments, i) Evaluation of cowpea genotypes, ii) Hybridisation of the selected genotypes in line x tester design, iii) Evaluation of F1 hybrids. The experiments were conducted at College of Horticulture, Kerala Agricultural University, Vellanikkara during 2014-2015. All the crop management practices were followed as per KAU (2011). Evaluation of cowpea genotypes revealed that there was wide variability for all the traits studied except branches per plant among bushy and semi trailing types of cowpea. In trailing type, variability was observed for plant height, number of pods per plant, pod weight grain yield per plant and seed protein content. Among the twenty two genotypes evaluated, ten genotypes that exhibited a protein content of above 25 per cent were selected for hybridization programme. The selected genotypes (Vellayani Jyothika, Bhagyalakshmi, Anaswara, Kanakamony, Lola, Vyjayanthi, AV-5, PKB-3, PKB-4 and Sharika) were hybridized in line x tester (6 x 4) design. High magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance was observed for plant height, grain yield per plant and length of pods were observed in parents and hybrids suggesting scope for genetic improvement of these traits through selection. Seeds per pod and protein content exhibited low PCV and GCV but high heritability and low genetic gain, indicating that these traits were governed by non-additive gene action and therefore breeding method other than simple selection is required. Combining ability analysis revealed that higher magnitude of specific combining ability (SCA) variances than the general combining ability (GCA) variances for the traits like pods per plant, length of pod, test weight, grain yield per plant and seed protein content indicating preponderance of non-additive gene action in the inheritance of these traits. Higher estimates of GCA variances over SCA variances for plant height, days to flowering, days to first harvest, days to last harvest, pod-weight and seeds per pod implies the preponderance of additive gene action in controlling these traits. The hybrids were ranked based on mean value, sca effects and estimates of heterosis for the traits like days to flowering, pods per plant, seeds per pod, test weight, grain yield per plant and protein content. Four hybrids with the lowest scores were selected. Hybrids H2 (Vellayani Jyothika x PKB-3), H10 (Anaswara x PKB-3), H11(Anaswara x PKB-4) and H12 (Anaswara xSharika) were found to be the most promising. The transgressive segregants with high yield and protein content can be identified on further evaluation of the segregating population from the above hybrids
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    Genetic make up of yield and yield attributes in a six parent dialiel cross of tomato
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1998) Siby Varghese; Chadramony, D
    An experiment in tomato (Lycopersicon esculentum Mill.) was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1995-96, with the objective of estimating the combining ability of parents, and gene action involved in the inheritance of different yield attributes. The study was conducted in a diallel model, using three bacterial wilt resistant varieties and three popular varieties. The three bacterial wilt resistant varieties were Sakthi, Arka Alok and Arka Abha. The three popular varieties were LE 79-5, LE 373 and PKM 1. These six parental varieties and fifteen hybrids were planted in the field in Randomised Block Design., with three replications. Observations recorded were plant height, number of branches per plant, spread of the plant, number of leaves per plant, number of days taken for first flowering, number of days taken for first harvest, duration of harvest, single fruit weight, fruit size, number of fruits per plant, fruit yield per plant, pericarp thickness, locules per fruit, number of seeds per fruit, reaction to pests and diseases, colour at collar of fruits and fruit cracking. Analysis of variance revealed highly significant differences among the genotypes for all the characters except for number of locules per fruit. Both g.c.a. and s.c.a. were significant for all these characters. The additive to \1 \3«;6 • dominance variance ratio indicated a preponderance for non-additive gene action in the characters such as spread of the plant, number of days for first flowering, number of days for first harvest and duration of harvest, and a preponderance for additive gene action in the remaining characters. Combining analysis showed that Sakthi and PKM 1 were good general combiners with respect to fruit yield and other yield attributes whereas LE 79-5 and LE 373 ",!ere good general combiners for the different vegetative characters such as plant height, branches and leaves per plant. Among the fifteen hybrid combinations, significant S.C.a. and heterosis were observed in the hybrids such as Arka Alok x PKM 1, Arka Abha x PKM 1, Sakthi x Arka Alok, Sakthi x Arka Abha and LE 79-5 x LE 373. Among these hybrids Arka Alok x PKM 1 showed significance for fruit yield, individual fruit weight, size of fruit, plant height, leaves per plant spread of the plant and also showed resistance to mosaic, fruit rot and fruit borer. The hybrid Arka Abha x PKM 1 showed significance for fruits per plant, fruit yield per plant, plant height, leaves per plant and spread of the plant. The combinations Sakthi x Arka Alok and Sakthi x Arka Abha showed high s.c.a. and heterosis for fruit weight, fruits per plant and fruit size and also high heterosis for fruit yield per plant. LE 79-5 x LE 373 exhibited high s.c.a. for fruit yield per plant and heterosis for fruit number and fruit yield. Therefore, these hybrids can be utilized for further crop improvement programme.
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    Combining ability for biological nitrogen fixation traits and yield components in blackgram (Vigna mungo (L.) Hepper)
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1996) Beena Thomas; Sreekumar, S G
    The research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1995-96. The objective was to assess the general and specific combining abilities and gene action involved in the inheritance of biological nitrogen fixation traits and yield components in blackgram, as a preliminary step for developing high yielding varieties with good biological nitrogen fixation capacity. The five lines, three testers and their 15 combinations were evaluated in a replicated field experiment and data on twelve characters were collected and subjected to line x tester analysis. The best general combiners for important biological nitrogen fixation traits were COBG305 and Pant U19 among lines and T9 among testers. The hybrid combination Pant U19 x T9 was the best specific combiner for these characters. In the case of number of pods and grain yield per plant, among. lines WBG-13 and among testers T9 were the best general combiners. The hybrids, LBG 17 x VBN 1 and WBG 13 x AKU4 were the best specific combinations for these traits. Considering the mean performance, sea effect and standard heterosis percentage Pant U 19 x T9 was identified as the best hybrid combination for nodule weight and nitrogen content at 50 per cent flowering. Regarding yield, the best hybrid was WBG 13 x AKU4. These superior combinations can be utilized further for developing improved blackgram varieties.