Dr. V. CHENGA REDDYBAYYAPU REDDY, K2017-10-112017-10-112015http://krishikosh.egranth.ac.in/handle/1/5810032878D5189The present study on “Genetic analysis of fibre quality traits in intra-specific hybrids of cotton (Gossypium hirsutum L.)” was conducted to elicit the information on the genetic diversity among the genotypes, character association, direct and indirect effects of yield components, type of gene action and combining ability effects in intraspecific hybrids of cotton, heterosis of hybrids, stability parameters of hybrids over environments for yield, yield components and quality characters and to identify the donor parents having favourable alleles. Ten parents (G. hirsutum L.) were selected based on their performance in genetic divergence study with 63 genotypes during kharif, 2012-13. Forty five intra-specific cross combinations were made in a half-diallel fashion during off season at RARS Lam Farm, Guntur, Andhra Pradesh. Evaluation of these hybrids along with the parents and standard check was carried out at three locations i.e., RARS Lam, Guntur, ARS, Jangamaheswarapuram and ARS, Darsi during kharif, 2013-14. The three methods of grouping revealed the presence of genetic divergence among the selected 63 cotton genotypes. D2 analysis and Ward’s minimum variance method grouped the 63 cotton genotypes into 8 clusters each. In D2 analysis, lint index followed by micronaire, seed index, days to 50% flowering contributed maximum for the divergence. In Principal component analysis seven principal components (PCs), contributed 84.004 per cent of cumulative variance. The first principal component contributed maximum towards variability (23.799). Ten divergent genotypes NDLH 1938, L 788, L 770, NA 1325, L604, SURABHI, RAH 1004, HYPS 152, MCU 5 and G COT 16 were selected for crossing based on their per se performance for different characters along with inter-cluster distance in Mahalanobis’ D2, principal component and cluster analysis. The analysis of variance revealed significant differences among the genotypes for all the characters under study. Wider genetic variability was observed for lint index, seed cotton yield plant-1 and lint yield plant-1. High heritability coupled with high genetic advance as per cent of mean was observed for number of bolls plant-1, seed index, lint index, ginning out-turn, micronaire, seed cotton yield plant-1 and lint yield plant-1. The character association analysis revealed that number of monopodia plant-1, number of bolls plant-1, boll weight, chlorophyll content, 2.5% span length, bundle strength and lint yield plant-1 has significant positive association with seed cotton yield plant-1 at both phenotypic and genotypic levels. The path coefficient analysis indicated that the number of bolls plant-1, boll weight, seed index, 2.5% span length and lint yield plant1 showed direct positive effects and significant positive correlation with seed cotton yield plant-1 indicating their importance in direct selection. The pooled analysis of variance of 56 genotypes (45 hybrids, 10 parents and 1 check) showed significant differences due to locations, parents, hybrids and various interactions indicating the existence of sufficient variation in the material under study. The ratio of gca to sca indicated the presence of non-additive gene action in all the characters except for days to 50% flowering and 2.5% span length. The gca effects from pooled analysis revealed that none of the parent recorded significant gca effects for all the characters. Among the parents, NDLH 1938 showed significant positive gca effects for most of the yield and quality characters. The crosses, NDLH 1938 × L 604, NDLH 1938 × RAH 1004 and NDLH 1938 × L 770, recorded high per se performance, significant positive sca effects and high standard heterosis over the standard check, Bunny, for seed cotton yield plant-1. Genotype × environment interaction studies with Eberhart and Russell model revealed that no hybrid had stable performance for all the characters in all the locations. The hybrids, NDLH 1938× NA 1325, NA 1325 × MCU 5, SURABHI × MCU 5, RAH 1004 × G COT 16 and MCU 5 × G COT 16 had stability for seed cotton yield plant-1 over locations. The hybrid, NDLH 1938 x L 604 predicted to perform well in the favourable environments and the hybrid, NDLH 1938 x L 770, predicted to show good performance in poor environments. Identification of unique favourable alleles in the donor parents analysis revealed that for improving NDLH 1938 × RAH 1004 hybrid for 2.5 % span length the donor parent SURABHI and for lint index L 788 and NA 1325 were showed significant positive μG' estimates. Whereas, for boll weight three parents, L 788, L 770 and L 604, showed the significant positive μG' estimates in combined analysis. Only one parent i.e., G COT 16, showed the significant positive μG' estimates in combined analysis for boll weight for improving NDLH 1938 × L 770 hybrid. The hybrids NDLH 1938 × L 604, NDLH 1938 × RAH 1004 and NDLH 1938 × L 770 recorded high per se performance, significant positive sca effects and high standard heterosis for seed cotton yield plant-1 along with yield contributing characters like number of bolls plant-1, boll weight, lint yield plant-1 and quality traits like 2.5 % span length, micronaire, bundle strength, uniformity ratio and elongation %. These hybrids may be tested over large number of environments for further confirmation before they are being exploited commercially.en-USnullThesis