Working Document Series Open Access 2012 RUF-32504

Genetic Analysis of Tropical Maize Inbreds and Hybrids for Grain Yield and Traits Associated with Drought Tolerance

P. GibsonC. MagorokoshoX. MhikeP. Okori

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Abstract

221 words

Drought tolerance is a complex trait, hence genetic improvement of this trait in maize requires indirect selection methods based on highly heritable traits that correlate strongly with grain yield. This study aimed at determining the modes of gene action for grain yield and stress related traits under well watered and water stressed environments. Fifteen inbred lines were crossed using the NCII Design (L10 x T5). The resultant 50 hybrids, 4 checks and the parental lines were evaluated under optimum and managed drought stress environments using a 0,1 alpha lattice design. The study showed significant GCA and SCA effects for grain yield and its secondary traits suggesting existence of both additive and non additive gene effects for the traits under review. GCA and heritability across environments for GY, ASI, EPP and SEN under drought were higher than in well watered environments. Correlations of secondary traits ASI, EPP and SEN with GY were stronger under drought than under optimum conditions. SCA and STI had better predictive value for F1 grain yield performance under drought. L2 and L7 can be released as CML lines and the AMMI stability analysis confirmed L2 x T2 hybrid can be used a new single cross tester for heterotic group A. Overall, selection in both stress and nonstress gives a better picture of the best performing hybrids across environments.

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