Department of Plant Breeding and Genetics, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh
Forty five F1s and 45 F2s derived from a 10 × 10 diallel mating design were studied for indirect selection response for some components and developmental traits and grain yield in wheat (Triticum aestivum L. em. Thell). Genotypic correlations were higher in magnitude than phenotypic ones. The significant associations were observed in 33 and 34 cases out of 55 possible correlations in F1s and F2s, respectively, twenty seven associations being common for both the generations. The correlations of grain yield with four component traits were not strong except in seven cases (F1s + F2s), exceeded ±0-5. Associations were in favourable direction between grain yield and 1,000-kernel weight, number of spikelets per spike and number of grains per spike in both the generations and between grain yield and number of productive tillers per plant in F1s. Thus, present material is amenable for simultaneous improvement in grain yield and its direct components. Amongst the six developmental traits, yield exhibited the strongest association with the synchrony of tillers. The presence of significant negative association between yield and days to flower indicated that it could be possible to breed early flowering recombinants with high grain yield.
Selection for developmental traits like plant height, days to flower, synchronous development, resistance to brown rust and component traits like 1,000-kernel weight, number of productive tillers per plant and number of grains per spike showed maximum correlated response in grain yield via these traits. The relative selection efficiency further indicated that direct selection might be more effective in early generations for all the traits under study except for early growth vigour where indirect selection may be more useful for improving the productivity of wheat.
