COMBINING ABILITIES OF GRAIN YIELD AND YIELD RELATED TRAITS IN RELATION TO DROUGHT TOLERANCE IN TEMPERATE MAIZE BREEDING

Temperate maize growing regions are increasingly prone to drought stress which is emerging as a primary constraint to maize productivity. Introgression of tropical sources of drought tolerance into temperate maize breeding may contribute to improving the drought tolerance of the relatively narrow temperate germplasm base that is currently in use. In the present study, seven tropical drought tolerant inbred lines and two well-adapted commercial temperate inbred lines were crossed in a half-diallel design. The 9 parents, 36 diallel hybrids and 2 commercial checks were tested in well-watered and managed water stressed conditions in Antalya, Turkey in 2013 and 2014. Significant differences were detected between genotypes for number of days to anthesis, anthesis-silking interval, plant height, thousand kernel weight, number of ears per plant, number of kernels per ear and grain yield. Tropical inbreds G1 and G5 were comparable to the adapted temperate commercial inbreds in terms of general combining ability. Specific combining ability analysis revealed that tropical x temperate hybrids had higher values compared to tropical x tropical hybrids. Yield potential of hybrid G5 x G9 in particular, a promising tropical x temperate hybrid, was significantly higher under both well watered and drought conditions. Our results suggest that tropical drought tolerant germplasm is likely to have high utility in temperate maize breeding programs.