RESPONSE TO THE DROUGHT OF A CORN HYBRID AND ITS F4 GENERATION

Abstract

was derived from this hybrid, in order to get an open poliination variety. The objective of this study was to determine if both cultivars show similar responses under water stress. The experiment was conducted under greenhouse conditions in Aguascalientes, México. Plants were grown in pots containing 19 kg of dry soil. The VS-201 cultivar was used as a control. Three soil moisture treat· ments were evaluated: R₀: plants without water restriccion, R₁: no irrigation during 15 days at at the flowering stage, and R₂ : no irrigation during 15 days at the early grain filling. Every treatment íncluded 12 plants of each variety. Results
indicated that the hybrid and the F₄ generation showtd similar responses to water stress in the two growth stages studíed. At R₁, both materials were less affected than the control VS-201: they showed less reduction in leaf area; earlier silk emergence; less reduction in grain yield (mean of 37% compared to 72% of the control) and in the total dry weight (mean of 66 g pl vs 138 g pl
of the control). They were not affected in i ts harvest index whereas thé control was reduted in 56%. At R₂ treatment the three cultivars were affected in a similar way in all the variables analyzed. within treatments, the F₄ generation showed a mean depreciation on grain yield of 11% respecto to the F₁•