Gene action controlling grain yield and secondary traits in southern African maize hybrids under drought and non-drought environments

Abstract

Breeding maize hybrids for drought tolerance would significantly reduce yield loss due to drought in southern Africa. Mode of gene action controlling yield and secondary traits was investigated by mating 27 inbred lines, in sets according to a North Carolina design II scheme. The resultant 72 experimental and eight commercial hybrids were evaluated in 8 · 10 a-lattice design with two replications, in four drought and two non-drought environments. Under drought conditions, only general combining ability (GCA) variance was significant for yield, indicating predominance of additive effects. In non-drought environments, both GCA and specific combining ability variances were significant for yield, indicating importance of additive and non-additive effects, respectively. Contributions of male (GCA m ) and female GCA (GCA f ) effects to hybrids varied depending on the trait and conditions. Superior GCA f to GCA m effects for yield under drought conditions, and for ASI, prolificacy and ear aspect under both drought and non-drought conditions, suggested that maternal effects might have modified these traits. Larger GCA m than GCA f for ASI and silking dates under normal conditions indicated that paternal genotypes played a greater role in determining these traits. Similar GCA m and GCA f for yield under normal conditions, silking and anthesis dates under drought indicated that both parents made similar contribution to hybrids. Possibly, complications due to modification of traits by cytoplasmic effects and cross-over G · E for yield might partly explain why only a few drought tolerant hybrids have been developed. Practical implications of these findings in breeding drought tolerance in maize are discussed.

Hybrids performance of doubled haploid lines derived from 10 tropical bi-parental maize populations evaluated in contrasting environments in Kenya

“…Significant variation for GY under drought observed in this study was an indicator of expression of differential levels of tolerance to drought in tropical maize hybrids. Beyene et al (2013) and Derera et al (2008) also reported differential responses of tropical maize hybrids to drought stress. Evaluations of maize varieties in multiple environments reveal a range of adaptation and specific fitness for diverse environments (Setimela et al, 2007;Beyene et al, 2013).…”

Combining Ability Analysis and Genetic Inheritance of Salt Tolerance Indicators in Maize (Zea mays) Following Diallel Mating Design

“…Previous studies reported the presence of genetic variability for different traits in maize under saline stressed environments (Betran et al, 2003;Derera et al, 2008). Significant differences among mean squares of GCA and SCA for different maize seedling traits showed that additive and non-additive gene effects are important for these parameters.…”

Daya Gabung Inbrida Jagung Toleran Cekaman Kekeringan dan Nitrogen Rendah pada Pembentukan Varietas Hibrida

“…Hal tersebut mengindikasikan genotipe 1044_30 yang bila digunakan sebagai tetua betina memberikan pengaruh lebih besar dalam pewarisan toleransi cekaman kekeringan dibanding sebagai tetua jantan. Derera et al (2007) dan Isnaini et al (2008) menyarankan penggunaan tetua betina toleran cekaman kekeringan dalam membentuk jagung hibrida toleran cekaman kekeringan.…”