Multi-environment Manifestation of Heterosis for Morphological and Quality Traits in Maize (Zea mays L.)

An investigation was carried out with 10 parents, their 45 hybrids mated in half-diallel fashion and 4 checks in RBD for estimation of heterosis in two environment (Kharif, 2014 and Rabi, 2014-15) at the Instructional farm, RCA, MPUAT, Udaipur, India. The average productivity of maize in USA is 11.07 MT ha-1 while, in India it is only 3.02 MT ha-1 during 2018-19. We lag far behind USA and are still not able to harness the optimum yield potential in maize that could partly be addressed by evolving hybrid maize cultivar. The present study aims to is identify heterotic hybrids that could yield stably with better grain quality over a range of environments. Environment wise Analysis of variance revealed that mean squares due to genotypes were significant for all the traits in both the environments. Partitioning of total genotypic variance indicated significant contribution of parents for all the traits. Mean squares due to crosses were significant for all the traits under study except for days to 50% tasseling. Mean squares due to parents vs. crosses were significant for all the traits except for days to 75% brown husk. Bartlett test showed homogeneity of error variance only for one trait i.e. grain oil content. The pooled analysis for grain oil content revealed significant differences between the environments. The mean squares due to genotypes including parents, crosses and parents vs. crosses were also significant. Significance of GE interaction for oil content indicates the influence of environments on the expression of this trait. The partitioning of GE interaction into those that by parents×environment and crosses×environment interaction were also significant. Two hybrids in E1, viz., P3×P6 and P2×P4 has shown significant negative economic heterosis for days to 50% tasseling, days to 50% silking and days to 75% brown husk. None of the hybrids has shown significant negative economic heterosis for these traits in E2 environment. The hybrid P3×P5 exhibited maximum positive economic heterosis (6.71%) for grain oil content over the best check HQPM-5 on pooled basis. The hybrid P5×P7 (2.78%) in E1 and P5×P10 (2.58%) in E2 exhibited maximum positive economic heterosis for grain starch content over the best check HQPM-1. The maximum positive economic heterosis for grain protein content was exhibited by hybrid P5×P8 (4.14 %) in E1 and by P3×P5 (2.49%) in E2 over the best check HQPM-5.