EPICUTICULAR WAXES CONTENT IN SORGHUM GENOTYPES IN RESPONSE TO WATER STRESS

Abstract

Twenty genotypes of grain sorghum (Sorghum bicolor L. Moench) were studied with respect to the responses of leaf epicuticilar waxes to drougth during 1991. Leaf samples which were taken after anthesis were analyzed for epicuticular wax content by extraction with chloroform and colorimetric analysis. Highly significant differences in leaf epicuticular wax content were found between genotypes. Wax content variet from 0.88 to 1.51 mg dm^-2 under irrigation and from 0.65 to 2.14 mg dm^-2 under drought conditions. A correlation coefficient of 0.72** between the average (average of drought + irrigation) wax content for each of the 20 genotypes ande the drought/irrigation wax content ratio was found also it was found a correlation coefficient of 0.90** between
the wax content under drought for each genotype and the drought/irrigation wax content ratio. We conclude that the increase in epicuticular wax content is a response to drought and the degree of response depends of the genotype and drought severity.