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Advances in Agriculture
Volume 2017 (2017), Article ID 7265726, 10 pages
Research Article

Effects of Drought on Morphological Traits in Some Cowpea Genotypes by Evaluating Their Combining Abilities

Department of Crop Protection and Environmental Biology, University of Ibadan, Ibadan, Nigeria

Correspondence should be addressed to Amos Afolarin Olajide

Received 30 May 2017; Accepted 14 August 2017; Published 20 September 2017

Academic Editor: Othmane Merah

Copyright © 2017 Amos Afolarin Olajide and Christopher Olumuyiwa Ilori. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


An evaluation was conducted to understand the genetic effects of combining ability for four different morphological traits, on 42 hybrids in randomized complete block design with three replications in water-stressed and well-watered environments. The significance of the additive variance (D) and dominance variance (H1) indicated the presence of both additive and nonadditive gene actions in both environments. Among the parents, there was asymmetrical distribution of positive and negative dominant genes and the preponderance of overdominance gene action for all the traits in both environments. This study also indicated a minimum of ten genes for plant height in water-stressed environment and minimum of three and eight genes for terminal leaflet area and number of leaves per plant in both environments, respectively. Estimates of narrow-sense heritability ranged from 13.0% for number of branches per plant in water-stressed to 95.0% in well-watered environment for terminal leaflet area. The study revealed that Danilla, IT93K-432-1, and IT97K-499-35 were the best general combiners for all traits, Danilla × IT97K-499-35, and Danilla × IT93K-432-1 were found to be the best specific combiners for all traits in water-stressed environment. Genetic interactions, additive × additive and additive × dominance, were more pronounced in the inheritance of the traits. This indicated that the selection for these traits should be delayed till advanced generations.