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20211
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Subject: Genetics and Plant Breeding × Author: Ali, Tabinda ×
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    ThesisItemOpen Access
    Effect on variability, character association and quality traits in gamma rays induced mutants of potential rice varieties (Oryza sativa L.)
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-03) Ali, Tabinda; Nautiyal), M.K.
    The present study was conducted at Norman E. Borlaug Crop Research Centre, GBPUAT, Pantnagar during the kharif seasons of 2018-19, 2019-20, 2020-21.In experiment 1the divergence analysis of M2 generation maximum percentage contribution to the total divergence in M2 generation for quantitative traits was made by Number of filled grains per panicle (35.786 %). The genotypes of M2 generation were grouped into five clusters, cluster I being the largest having eight genotypes and cluster V being the smallest having one genotype only. Cluster I had the highest intra cluster D2 value (169.51) followed by cluster IV (169.10) and cluster II (146.27). The highest inter cluster distance was observed between cluster III and cluster V (1360.03) followed by cluster III and cluster IV (1296.87), cluster I and cluster V (1235.69) and lastly cluster II and cluster III (1163.80) indicating very clearly that the genotypes of these clusters could be used in hybridization programs. Inter character correlation coefficient at phenotypic level indicates that panicle length has a significant and positive correlation with yield per plant (0.459), panicle length has a significant and positive correlation with thousand grain weight (0.486). Thousand grain weight has a highly significant and positive correlation with yield per plant (0.849). On the analysis of quality traits of M2 generation, Pearson’s correlation revealed that a number of quality traits are having a highly significant and positive correlation with the other quality traits. Divergence analysis resulted in the grouping of genotypes into four clusters. Cluster I has the largest number of genotypes (twelve) whilst cluster IV has lowest number of genotypes (only one). Cluster III has the highest intra cluster D2 value (302.37) followed by cluster II (226.61) and cluster I (216.49). The highest inter cluster D2 value was observed between cluster II and IV (1160.31) followed by cluster III and IV (919.46), cluster I and II (765.10) and ultimately cluster II and III (473.90). The genotypes of these clusters could be used in the hybridization programs. Among various quality traits in M2 generation, highest contribution to diversity was given by head rice recovery percentage (48.599 %) followed by kernel length (24.489 %), gel consistency % (9.919 %) and alkali digestion value (7.517). In M3 generation ANOVA revealed significant differences for all the traits under study. The diversity analysis of quantitative traits of M3 generation revealed that cluster IV had the highest intra cluster D2 value (98.071) followed by cluster I (96.678) and cluster III (92.376).The highest inter cluster distance was observed between cluster II and cluster III (1496.967) followed by cluster II and cluster V (1039.585) and cluster III and cluster VI (941.687). This indicates that the genotypes of most distant clusters will serve as potential parents in the hybridization programs.Maximum contribution to the genetic divergence was provided by the trait days to maturity (30.04%) followed by thousand grain weight (27.30%), days to flowering (21.04 %), number of panicles per plant (4.81%) and yield per plant (4.25%). The genotypes were grouped into six clusters with cluster I being the largest having 13 genotypes and cluster V and VI being the smallest clusters, having one genotype each. Inter character correlation coefficients between different characters at genotypic level in M3 generation reveals that panicle length has a significant and positive correlation with yield per plant (0.422) and thousand grain weight has a highly significant and positive correlation with yield per plant (0.828). Direct selection for these traits can lead to enhancement in the yield of grains per plant. Pearson’s correlation has been worked out to find out the correlation among various quality traits. Most quality traits have a highly significant and positive correlation with the other quality traits. The divergence analysis of quality traits in M3 generation on the basis of D2 statistics resulted in the grouping of genotypes into six clusters. Cluster II being the largest (sixteen genotypes) and cluster V and VII being the smallest clusters (one genotype each).In terms of quality in M3 generation maximum intra cluster distance was observed in case of cluster IV (297.19) followed by cluster II (225.49) and cluster III (190.09). Maximum inter cluster distances was observed between cluster III and IV (2322.47), cluster III and V (1336.40) and cluster I and IV (1251.92). Crosses can be made among the genotypes of the most diverse clusters. Maximum contribution to the total diversity in terms of quality is made by head rice recovery percentage (32.75%) followed by kernel length after cooking (27.53 %) and gel consistency (16.08 %). In the phenotypic screening for BLB in M2 generation five resistant types mutants have been found among twenty-one lines namely, UPR-7029- 10 kR, Jhumri selection-3-10 kR, Jhumri selection-3-20 kR, Jhumri selection-7-10 kR and Jhumri selection-7-20 kR. Furthermore, in M3 generation eight resistant types have been screened among the twenty- six lines namely, UPR-7029- 10 kR-12, UPR-7029- 20 kR-4, UPR-7029- 20 kR-2, UPR-7029- 20 kR-3, Jhumri selection-3-10 kR, Jhumri selection-3-20 kR, Jhumri selection 7- 10 kR and Jhumri selection -7 -20 kR dose. In the second experiment Analysis of variance for assessing the effect of the split doses of GA3 on the female parental line revealed that on increasing the dose of gibberellic acid there was a corresponding increase in the plant height. Number of tillers per plant also increased on increasing the dosage of gibberellic acid. Similar trends were observed in case of length of exerted panicle, panicle exertion percentage, number of filled spikelets per panicle, seed setting percentage and seed yield.