Genetic parameters of drought tolerance related traits in tropical maize

The selection of drought tolerance related traits in maize has been object of interest in improvement programs, mainly in function of the selection inefficiency for grain yield on these conditions. The objective of this work was to estimate genetic parameters in two populations of tropical maize. Two populations (called D and U) with 256 F progenies had been evaluated in a 16×16 simple lattice, in seven and nine environments with population density of 62,500 plants ha. Significant differences were observed among line (P), environments (A) and for the P × A interaction in both populations. The heritability coefficients at progenies level average had varied between 73.52% for prolificacy in population D and 95.88% for female flowering (FF) in population U. Grain yield (PG) presented significant genetic correlation in populations U and D, respectively, with prolificacy (0,79 and 0.88) and female flowering (-0,76 and -0,44); in population U with male flowering (-0.74) and; in population D with stay-green (-0.50). No genetic correlation was observed between PG and anthesis-silking interval (IF). Estimated of genetic parameters suggest that the use of selection indices that include, besides PG, characters as prolificacy, FF and SG in the selection process under conditions of normal water supply, could lead to the development of cultivars with high grain yield and good drought tolerance.