The objective of this study was to evaluate the performance and the traits involved in the responses of three soybean genotypes to high intensity drought stress under greenhouse conditions. The experiment was carried out at the Greenhouse and Horticulture Station Professor Mario César Lopes, NEE/UNIOESTE Marechal Cândido Rondon, PR, Brazil, in 2007. Were evaluated three soybean genotypes (CD 201, CD 202 and CD 217) subjected to a high intensity and short drought stress period. The experiment was arranged in a (3x2) factorial completely randomized design with five replications. Drought stress was induced at the beginning of the reproductive stage by watering suspension. Soil moisture content (Ug) and relative leaf water content (RWC) were measured during drought stress and rehydration period. Protoplasmic tolerance was evaluated before rehydration and the biometric parameters were determined after the recovery period. Yield and yield components were determined at the end of crop cycle. Soybean genotypes were differently affected by drought stress regarding water status and leaf area maintenance, and consequently the yield potential. The differences among the soybean genotypes could be verified even at high drought stress intensity, with CD 202 showing the best performance. Water status and leaf area maintenance must be considered as characteristics of interest for drought tolerance improvement in soybean breeding programs.
Glycine max L. (Merrill); leaf area; leaf protoplasmic tolerance; relative water content; soil water
