ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 92 Number 3
Response of quality protein maize inbred lines to seedling drought stress. (184)
Maize is an important source of nutrients for many households in South Africa. The crop is susceptible to drought at all growth stages. Seedling drought stress is one of the most important abiotic stresses occurring in farmer’s fields, though screening for tolerance at this stage of growth has been largely neglected. An experiment was conducted to study the response of twenty–one inbred lines to seedling drought stress. Maize seedlings were exposed to two moisture levels, 25% and 75% field capacity, in a randomised complete block design with three replications. Seven drought indices were calculated based on total dry weight under both moisture conditions. Total dry weight under drought stress and nondrought stress conditions were significantly (P 0.05) correlated with stress tolerance index (STI), mean productivity (MP) and modified stress tolerance index (MSTI). Principal component analysis revealed that the first two components had eigenvalues greater than 1, with a proportional cumulative variance of 99.6%. The biplot were identified L2, L3, L6, L8, L9, L10, L11 and L16 as the most drought tolerant lines. In this study, STI, MSTI and MP were the most suitable indicators for screening for drought tolerance at seedling stage. The above inbred lines can be used as parents for improvement of drought tolerance in breeding programs.
Keywords: drought stress, drought tolerance index, maize seedlings