Among the environmental stresses, drought is considered the main source of maize grain yield instability in tropical areas. Anthesis-silking interval (ASI) is used as an efficient phenotypic index for water stress tolerance and has also been used in breeding programs aiming to increase yield stability under water stress. This phenotypic index is also an important tool to be used in cultivar development, in relation to the emergence of silk hairs, since the ASI is totally independent from the differences in genotype cycles. The objective of this study was to evaluate the genetic potential of six maize inbred lines from the Embrapa Maize and Sorghum breeding program, selected for drought tolerance by using grain yield. The F 1 's and reciprocals from a diallel crosses, plus three hybrids checks, were evaluated under two irrigated systems: well-watered conditions during all growth stage and water-stressed conditions where irrigation was suppressed during the flowering period. The means over the checks were 15% and 5% higher than the means of all F 1 's hybrids in the experiments under non-stress and stress conditions, respectively. Under water-stressed conditions, yield means were 45.6% and 40.4% low for the checks and F 1 's, respectively, when compared to well-watered condition. The results for mean grain yield showed a great potential for the genetic material used in the ecological condition studied. Under well-watered conditions, the F1's L1147 x L10.1.1; L6.1.1 x L8.3.1 and L1147 x L13.1.2 and the reciprocal cross L13.1.2 x L1147 presented the highest specific combining ability effect values. For both conditions, general combining ability effects of the inbred line L6.1.1 showed the highest value and the inbred lines L10.1.1 and L1147 the lowest ones. Under water stress, the specific combining ability effects were not significant among F 1 's and reciprocals, indicating similar performances for crossing combinations among the evaluated lines. The grain yield means of the checks were similar to the means of the F 1 's in both environments. Among the hybrid checks, the single cross presented a higher grain yield than the three-way and double-crosses hybrids, in both well-watered and under water-stress conditions.

There is genetic variability in Phaseolus vulgaris L. with regard to sensitivity to environmental stress situations, such as heat stress and water deficiency. This variability may have been originated by natural selection or plant breeding processes. The objective of this experiment was to evaluate some physiological and biochemical characteristics in common bean plants submitted to water stress and to different salicylic acid doses. Two varieties were grown in 20L pots until the development of the third leaf. The plants were treated with salicylic acid (zero, 0.025, 0.05 and 0.1mM) every three days for nine days. Then the plants were not watered for nine days until they reached the wilting point. The effective and potential quantum efficiency and electron transport rate were measured during and after stress. Proline content, SOD activity, soluble protein content and dry matter was measured 24h after rehydratation. Salicylic acid induced alterations in the population Guarumbé while Aporé reacted insensitively to salicylic acid regarding photosynthetic parameters.