Genetic architecture and character association studies in bread wheat (Triticum aestivum L.)

Abstract

The present field experiment was conducted at the CRC of SVP University of Agriculture and Technology, Meerut (Uttar Pradesh) India during Rabi 2019-20 and 2020-21 for attempting of crossing programme in a line × tester (10 lines × 4 tester) and developed 40 F1s was laid out in Randomized complete Block Design with three replications. The Data were recorded for twelve characters namely, days to 50% flowering, days to maturity, plant height (cm), number of productive tillers per plant, peduncle length (cm), spike length (cm), spikelets per spike, number of grains per spike, 1000 grain weight (g), biological yield per plant (g), harvest index (%) and grain yield per plant (g). Analysis of variance revealed that there was significant variability present among all the genotypes for all the characters studied. The magnitude of phenotypic coefficient of variation was higher than genotypic coefficient of variation for the all characters revealed favourable degree of interaction of genotypes with the environment. High heritability is associated with moderate genetic advance for harvest index and spike length. Correlation coefficient for grain yield per plant had positive and highly significant association with harvest index, biological yield per plant while, negative and non-significant association with days to 50% flowering and days to maturity at both genotypic and phenotypic level. Path coefficient analysis for biological yield per plant followed by harvest index had high positive direct effect at both genotypic and phenotypic levels. The analysis of variance for combing ability the line × tester set showed were highly significant for harvest index, plant height, 1000 grain weight, days to 50% flowering, biological yield per plant, grain yield per plant and number of productive tillers per plant. Estimates of SCA variances were higher than GCA variance for harvest index, plant height, biological yield per plant, 1000 grain weight, days to 50% flowering, grain yield per plant, days to maturity and number of productive tillers per plant showed the preponderance of non-additive gene action.The maximum proportional contribution to the total variance was due to female lines than those of the males. The GCA effect parents UP1109, DBW187 and HD3237 were found good general combiners for grain yield per plant. The SCA effects were observed in the crosses like HD3237 × WR544, RAJ 3777 × HD3086 and DBW187 × HD3086 were found good specific combiner. Heterosis over the better parent the highest significant and positive values were observed for UP1109 × WR544, UP1109 × PBW226 and HD3237 × WR544. Heterosis over the mid parent the highest significant and positive values were observed for HD3237 × WR544, UP1109 × WR544 and UP1109 × PBW226. Twenty SSR marker revealed total 52 bands were obtained with an average 2.6 bands per primer. Out of 52 bands, 47 were polymorphic and 5 were monomorphic bands. The minimum genetic similarity was observed among PBW175 × WH1105 - HD2177 × WR544 whereas, the highest genetic similarity was present among genotype HD2177-PBW373, K9162-NW5054 and UP2628-DWR544.