Evaluation of drought tolerance in maize (ZEA MAYS L.) using physiological indices

Drought is a threat to global food security. To develop drought tolerant high yielding maize varieties effective screening techniques for drought tolerance are required. In the current study, an effort is being made to screen maize cultivars for drought tolerance. Twelve maize cultivars were assessed for drought tolerance under laboratory conditions using physiological indices like germination stress tolerance index (GSI), shoot length stress tolerance index (SLSI), root length stress tolerance index (RLSI), fresh and dry biomass stress tolerance index (FWSI, DWSI). The data so collected was combined to various multivariate techniques which includes correlation and cluster analysis to evaluate the diversity for drought tolerance in maize cultivars. Positive and highly significant correlations were found between GSI, and DWSI. Cluster analysis classified 12 cultivars into three divergent groups. The members of first cluster (Malika, Sahiwal gold YY-15, MMRI yellow, Pop-Corn YPC-15) showed adequate degree of drought tolerance based on different physiological stress tolerance indices, whereas, cluster-2 included cultivars (Sweet Corn YSC-15, R1 czp, Pearl, Gohar 786) with moderate level of drought tolerance and cluster-3 included maize cultivars (Salman, Sahiwal 2002, Sadaf and Akbar) with lowest level of drought tolerance and did not give good performance. The results and scores achieved indicated that for drought tolerance in maize, physiological indices can be used as a screening tool. (author)