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19993
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Subject: Genetics and Plant Breeding × End date: 1999 × Start date: 1999 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Estimation of combining ability and heterosis in snakegourd
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Radhika V S; KAU; Abdul Khader, K M
    A diallel analysis in snakegourd iTrichosanthes anguina. L.) was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during the period 1997-1999. The research work was taken up to assess the general and specific combining abilities, nature of gene action and also to estimate the heterosis for various characters. The six parents involved were selected from a previous D2 analysis conducted in the Department and were the most divergent ones. They are PI (Nedumangad local), P2 (Thrikkannapuram local), P3 (Kanhangad local - 3), P4 (Vlathankara local), Ps (Kaumudi) and P6 (Idukki local). The observations were recorded on yield and yield attributing characters. Significant differences were detected among the mean performance of the genotypes, for all the characters studied. The combining ability analysis revealed that the parent P, (Kaumudi) was the best general combiner for most of the yield and and yield contributing traits. The hybrids PI x Ps, P2 X P, and P2 x P6 were superior specific combiners in yield characters like mean weight of fruit, number of fruits per plant and fruit yield per plant respectively. The crosses involving P, and P6 were found to be good specific combiners for yield and yield contributing characters. The variance due to general and specific combining ability was significant in almost all the characters studied indicating the significance of both additive and non additive gene action in the characters. The sea variance was found to be more than gca variance in most of the characters studied indicating the predominance of non additive gene action. The ratio of additive to dominance variance was less than one in most of the characters again indicating the predominant influence of non additive gene action which strongly substantiated the validity of the heterosis breeding method in improving the crop. Manifestation of heterosis was seen for all the characters studied. Among the hybrids, P2 x Ps had the maximum standard heterosis for yield and yield related characters. The crosses PI x Ps, P, X P(, and P3 x P, also exhibited significant standard heterosis for these characters. In general the hybrids involving the parent Ps was found to be more heterotic.
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    ThesisItemOpen Access
    Intervarietal hybridization in Anthurium andreanum Linden
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Renu, R S; KAU; Mercy, S T
    The present study on evaluation of morphological characters and compatibility reactions among ten selected Anthurium andreanum varieties, was undertaken to analyse the scope for genetic improvement in this crop. The analysis of variance revealed significant variation among the ten varieties for the twelve quantitative characters studied. This reveals the high genetic potential for the improvement of this crop. Variability studies indicated that high phenotypic and genotypic coefficients of variation for the characters plant height, position of candle, days to initiation of female phase, number of days in female phase and spathe size. The characters with heritability coupled with high genetic advance values were plant height, spathe size, spathe-candle ratio, position of candle, number of flowers per candle and days to initiation of female phase, indicating additive gene action. Plant height was found to be positively correlated with number of leaves or spadices per year. Spathe size and candle length were positively correlated. Candle length had high positive genotypic correlation with position of candle and number of flowers per candle. Pollen fertility ranged from 42 per cent in Liver Red to 13.7 per cent in Mauritius Orange. Study of pollen emergence pattern revealed significant differences among the varieties. Pollen emergence was completely absent in Pompon Red, Nitta Orange and Midori Green during the period of study. Pollen production was high in the cooler months of October to December and was suppressed during the hot months of March to June. Cross compatibility analysis based on the results of intervarietal hybridisation was done using the three parameters; i.e., percentage of candles bearing fruits, percentage fruit set and percentage seed •germination. The percentage of fruit bearing candles were highest for Nitta Orange (51.93 per cent) and lowest for Mauritius Orange (9.51 per cent). The only two selfings that produced fruiting candles were LR x LR and DT x DT. The number of fruits per candle ranged from five to 183. The variety Pompon Red had the highest average number of fruits per candle and it was lowest for Lady Jane. The percentage of fruit set was below 50 per cent for all the crosses except PR x LR. The crosses involving Pompon Red as female parent had the highest percentage of fruit set. The number of days taken for seed germination varied from three to twelve days. The seed germination was highest (87.5 per cent) for the cross DT x MW. Among the varieties it ranged from 69 per cent in Tropical Red to 2.3 per cent in Midori Green. Seedling survival at four to six month stage was highest for the crosses of Mauritius Orange and the lowest for those of Midori Green. The cross TR x MW showed 100 per cent seedling survival. Scoring of the compatibility reactions based on fruiting candles, fruit set and seed germination, on a scale ranging from O to 9, showed the highest compatibility' score of nine for PR x LR and CR x MW crosses. The best female parents were identified as Nitta Orange, Liver Red and Pompon Red based on the overall performance. The analysis of the performance of varieties as pollen parents on the same basis showed that Ceylon Red, Merengue White and Liver Red are the best pollen parents. These observations showed that the performance of a variety as female parent was different from its performance as male parent. Only the variety Ceylon Red and Liver Red performed well both as female and male parent.
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    ThesisItemOpen Access
    Genetic analysis of segregating generation of inter varietal crosses in greengram
    (Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Ebenezer Babu Rajan, R; KAU; Wilson, D
    The research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, VelIayani during rabi season 1998-99, with the objective of identifying superior progenies in the F2 generation for yielding ability and nitrogen fixation 'potential. Seven parents and F 2 progenies of their 21 crosses of greengram were evaluated, adopting a randemised block design with three replications. The data collected for thirteen quantitative characters were analysed statistically. The genetic parameters, correlation and path coefficients were studied and a selection index was formulated to identify superior genotypes. The treatments showed significant difference for all the characters. High genotypic coefficient of variation was observed for weight of nodules in the root at 50 per cent flowering, dry weight of plants at maturity, nitrogen content of plants at maturity and grain yield. High heritability coupled with high genetic advance was observed for weight of nodules in the root at 50 per cent flowering followed by dry weight of plants at maturity, grain yield, number of pods, number of cIuslters per plant, harvest index, hundred grain weight, number of secondary roots at maturity, plant height and shoot/root ratio indicating additive gene action and reliability of these characters during selection programme for crop improvement. High positive genotypic correlation for number of pods per plant followed by number of clusters per plant, harvest index, plant height, hundred grain weight and number of seeds per pod indicated selection based on one or more of the above components may result in the improvement of grain yield. The path coefficient analysis revealed high positive direct effects of number of pods on grain yield. In addition hundred grain weight and number of seeds. per pod also showed positive direct contribution to grain yield. A selection index was constructed based on grain yield per plant and eight yield contributing characters identified through correlation and path analysis. Based on the selection index one of the parental varieties CoGG-902 ranked first followed by Pusa-9333 x NDM-88-14, Pusa-9333, KM-1285 x CoGG-902 and IlPRM-3 x LG-444 were identified as superior for yielding ability and nitrogen fixing potential.