SELECTED AND NON-SELECTED MAIZE HYBRIDS BEHAVIOR FOR ASI UNDER WATER STRESS IN FLOWERING AND GRAIN FILLING

Abstract

Among abiotic stresses, drought is one of the most serious problem that reduces maize production. This reduction depends on the development of the culture and on the scarcity of water. The Anthesis Silk Interval (ASI) has been related as a trait of easy measurement and it is negatively correlated with drought tolerance. The objective of this work was to verify the hybrids behavior originated from selected and non-selected inbreed lines for ASI under water stress during flowering/grain filling stages. The applied irrigation was measured in collecting cans placed in each experiment. In the experiment with stress the irrigation was interrupted at 55 days after planting date (dap) and initiated again at 90 dap. To evaluate the applied water stress, soil-water was monitored in three depths of the soil profile (0-20, 20-40 and 40-60 cm) using the gravimetric method. Ten non-selected hybrids for ASI (NSASI), five hybrids with 100% ASI, five hybrids with 50% ASI and two commercial checks were used. For both trials the experimental design was randomized complete blocks with three replications and a plot formed by two five-meter-long rows. Significant differences were found (P<0.01) for all evaluated traits in each environment and for grain weight, ear number and plant height in the combined analysis. The hybrids with ASI 100% showed, in average, zero ASI and they showed protogyny while the others showed protandry. The NSASI hybrids showed an average reduction of 62% in the productivity while hybrids with 100% ASI and 50% ASI showed average reductions of 44,8% and 54%, respectively. The highest average productivity of the ASI hybrids in the environment with moisture stress seems to be more associated with the higher ear number than with the ASI trait.

Keywords

• anthesis silk interval
• drought tolerance