Genetic Variation in Fifty-Three Maize Inbred Lines in Relation to Drought Tolerance at Seedling Stage

【Objective】Drought is a potential major constraint to maize stable production. Identification of drought-tolerant germplasms in seedling stage is an efficient way to exploit useful genes【.Method】In this study,using leaf relative water content,leaf water conservation,MDA content and seedling survival rate as standard indexes,53 inbred lines were evaluated for drought responses in greenhouse under water-stressed and well-watered conditions during 2005 in Beijing,China.【Result】The evaluation resulted in identification of 13 drought-tolerant,16 moderately tolerant and 24 susceptible inbred lines,respectively. Under water-stressed condition,drought tolerant lines were found to show higher relative water content,water conservation and lower MDA content,while the cases reversed for drought susceptible lines. Leaf relative water content and water conservation were two important traits indicating drought responses at seedling stage in maize. The diversity at DNA level was investigated applying 63 SSR markers. The total number of alleles was 245,and the mean of polymorphism information content was 0.596. The UPGMA analysis showed that 53 inbred lines could be classified into six sub-groups (Lancaster,BSSS,PA,Luda Red Cob,Sipingtou and PB),which were generally consistent to their known pedigree records and other breeder's experiences. Comprehensive differences were observed on mean leaf relative water contents,leaf water conservation and seedling survival rate among the six sub-groups. Thelevels for BSSS,Sipingtou and PB were found to be relatively high.【Conclusion】BSSS,Sipingtou and PB were identified as the important sources of drought tolerance. 21 SSR alleles were significantly associated with drought tolerance,which could be employed for evaluating the inbred lines of maize to drought responses at DNA level.