Conservation agriculture facilitated assessment of genetic potential of new generation maize hybrids and improving the breeding efficiency

To meet the increasing demand for maize grains in India, high-yielding maize hybrids have to be released in the farmer’s field for adoption during kharif. The current study was carried out to estimate the potential of new generation hybrids generated by crossing the inbreds developed through a repeated cycle of recurrent selection in maize (Zea mays L.) under conservation agriculture conditions maintained under a maize-wheat cropping system. We hypothesised that soil health is a major determinant of yield realisation, particularly during Kharif in northern plain conditions, and therefore conservation agriculture can facilitate the identification of hybrids with high yield potential. In contrast, conventional tillage does not support the hybrids of high yield potential. To test the hypothesis, 91 hybrids developed by crossing 14 inbreeds in a half-diallel fashion were grown along with parents in both conservation and conventional tillage conditions. The result of the analysis of variance (ANOVA) showed significant variance for all the traits under study in both conditions. Combining ability estimates showed that most of the traits involved both additive and non-additive gene actions. Phenology along with radiation use efficiency by better capturing the sun light plays an important role in yield maximisation as indicated by the contribution of PMICS20, PMICS11, PMICS13 PMICS17 and PMICS12 for optimization of days to silking, maximising LAI and stem girth for higher yield realisation at least under conservation agriculture through additive gene action of complementary alleles dispersed in the parents or because of non-additive gene action at some of loci in hybrids like PMICS20/PMICS11, PMICS17/PMICS12 and PMICS15/PMICS12. Population improvement programme through repeated crossing to combine the favourable genes and selection under conservation agriculture for slightly delayed silking, along with higher LAI, more number of grains per row, grain weight and stay grain trait can lead to the development of hybrids competing with rice in terms of economic return.