African Journal of Plant Breeding ISSN: 2375-074X Vol. 9 (8), pp. 001-013, August, 2022. © International Scholars Journals
Full Length Research Paper
Combining ability analysis for drought tolerance among single-cross tropical maize (Zea mays L.) hybrids in semi-arid Kenya
Dorothy Wanjala Wachenje1, Pascal P. Okwiri Ojwang1 and Murenga Mwimali2
1Department of Crops, Horticulture and Soils, Egerton University, P.O. Box 536-20115, Njoro, Kenya.
2Kenya Agricultural and Livestock Research Organization, P.O. Box 57811-0200, Nairobi, Kenya
Accepted 26 July, 2022
Drought stress is a major challenge in maize (Zea mays L.) production negatively impacting on production in semi-arid areas of eastern Africa. Breeding hybrid cultivars for semi-arid areas is essential to reduce yield losses experienced under rain-fed maize production. The objective of this study was to estimate combining ability for drought tolerance among single-cross maize hybrids in semi-arid environments. Eleven parents with known drought resistance were crossed in a half diallel mating design to generate 55 crosses, the Griffing’s diallel method IV, model II was used in analysis. The F1s, alongside two local checks, were evaluated in α-lattice design with two replications during 2020/2021 cropping season. Combined analysis of variance over environments revealed significant (p<0.05) main effects for genotypes, locations, and genotype-by-location interactions in most traits studied. Significant (p< 0.05) general combining ability (GCA) and specific combining ability (SCA) for grain yield, ear height and plant height demonstrated the role of additive and non-additive genetic variance in inheritance of these traits. Hybrids KAT-DT-EE-07×KAT-DT-EE-14 and KAT-DT-EE-07×KAT-DT-EE-04 had superior grain yield of 6.18 t ha-1 and 6.16 t ha-1, respectively. KAT-DT-M-31×KAT-DT-EE-07 showed significant SCA for grain yield which demonstrated the potential of obtaining drought tolerant hybrids for possible deployment to farmers.
Key words: drought stress, general combining ability, heritability, hybrid cultivars, specific combining ability.