PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

Twelve Malaysian rice genotypes were evaluated for drought-related morphological and physiochemical responses to determine the degree of genetic divergence. Preliminary investigation showed a considerable reduction in plant growth, total chlorophyll content, chlorophyll stability index (CSI %), and total soluble protein in all the genotypes studied. On the other hand, a sharp increase in the accumulation of proline was also noticed. An analysis of variance revealed significant variations for those traits among the genotypes, which was adequate for the estimation of genetic diversity. Hierarchical cluster analysis of multivariate approach was performed for the genotypes exposed to water deficit stress as well as for the control conditions. Meanwhile, the genotypes were classified into groups based on the deferential responses. However, the analysis was unable to reveal how sensitive or tolerant the genotypes to drought condition, hence a discriminant functional analysis was carried out. The result obtained from canonical discriminant function clearly distinguished the genotypes based on sensitivity to drought stress. Furthermore, the study demonstrated the relevance of morphological and physiochemical responses in screening drought tolerance in rice. Hence, it is suggested that discriminant functional analysis can be used as a potential screening tool to identify drought tolerance genotypes at early stages in rice.