Articles

Determinants of drought tolerance at seedling stage in early and extra-early maize hybrids


Abstract


Adequate knowledge of response of genotypes to stress and identification of important adaptive traits under stress conditions facilitate rapid progress in a breeding program. The objectives of this study were to evaluate the response of early and extra-early maturing maize hybrids to drought stress imposed at seedling with a view to identifying tolerant hybrids for further breeding studies and identify adaptive traits that could be used as selection criteria for tolerant maize genotypes at this growth stage. This study was conducted in the screenhouse in the Faculty of Agriculture, Obafemi Awolowo University, Ile-Ife, Nigeria. Five seedlings each of 15 hybrids each from early- and extra-early-maturity groups were raised in pots and the pots were arranged in a randomized complete block design with three replicates. The experiment was adequately watered for the first seven days and thereafter watering stopped. The plants were observed for 42 days and data were recorded on emergence and other seed- ling traits. Data collected were subjected to analysis of variance, principal component analysis and correlation analysis. Results showed significant difference between maturity groups for root length and significant difference among genotypes within maturity were obtained for total number of leaf shed, moisture content of root, fresh shoot weight, total fresh biomass and seedling aspect, indicating there was wide variability in the response of the genotypes from the different maturity groups for tolerance to drought at seedling stage. Principal component analysis also identified these traits as the primary traits contributing to diversity among the hybrids under induced drought at seedling stage. Results of correlation analysis showed differential association among traits of early and those of extra-early maize, indicating that mechanism of tolerance to drought in the two maize maturity groups are different. It was concluded that early and extra-early maize hybrids responded differently under drought stress imposed at seedling stage and that seedling stage total number of leaf shed, moisture content of root, fresh shoot biomass, and total fresh biomass were important drought adaptive traits and the traits should be included in computing base index for selecting drought tolerant maize at seedling stage.

Keywords

biomass, drought, maize, principal component, seedling aspect

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Maydica - A journal devoted to maize and allied species

ISSN: 2279-8013