RESPONSE OF CORN GROUPS OF DIFFERENT EARLINESS TO STAGES OF CONTROLLED DROUGHT

Abstract

Nine varieties of rainfed corn (Zea mays L.), classified into three earliness groups with 3 varieties per group, were subjected to four unique periods of drought in the following four phenological stages: from emergence to 30 days, from 30 to 60 days, 60 to 90 days and 90 to 120 days after sowing. Each drought stage consisted of suspending irrigation for approximately 30 days, except in the control treatments which were maintained with usable soil moisture throughout the cycle. Highly significant differences were observed between the effects due to drought stages, earliness and varieties within groups, but the interactions between drought stages and degree of earliness and of these with varieties were not significant. Phenotypic correlations between days to flowering, grain and biological yield, harvest index and other eight traits were positive and highly significant. There was no correlation between leaf area and harvest indices.