Foliar carbohydrate content in maize hybrids submitted to water restriction

Abstract

Water deficit is one of the main problems of agriculture and the ability of plants to overcome this stress is of great importance for the development of cultivars in breeding programs, especially in crops such as maize. The objectives of this work was to study the response of the carbohydrate content in the leaves and to verify the performance of the biometric characters in contrasting maize hybrids as to the drought tolerance during the water deficit in two phenological stages of the crop. The hybrids used in the study were DAS2B707 and DAS2B710 considered drought tolerant, due to hight performance and yield when submitted to water shortage conditions and FT510 and AS1522, considered sensitive according to results in the regional maize trials in second season at São Paulo state. A split plots design was used with three replications. The plots consisted of the three water regimens: (a) control – plants irrigated throughout the cycle; (b) water deficit from the vegetative stage (V5); and (c) water deficit from the flowering stage (R1), while the subplots consisted of the four hybrids. In general, the water deficit in the two phenological stages of the crop reduced leaf carbohydrate content, plant height, stem diameter, grain mass and total dry mass of practically all evaluated hybrids. The DAS2B707 showed a higher grain yield when there was a water deficit from the vegetative stage, indicating a higher potential under drought conditions. AS1522 was considered drought tolerant from the flowering stage due to the high content of sucrose obtained under water deficit conditions, characterizing an osmotic adjustment.