Combining Ability of Early‐maturing White Maize Inbreds under Stress and Nonstress Environments

Abstract

Maize (Zea mays L.) hybrids resistant to Striga hermonthica (Del) Benth and tolerant to drought are vital to the sustainability of productivity of the maize‐based farming systems of West and Central Africa (WCA). Thirty‐six diallel crosses derived from nine early maturing white maize inbreds were evaluated under drought, well‐watered, striga‐infested, and striga‐free conditions at five locations in Nigeria between 2007 and 2009. The objective was to examine the combining ability, performance and stability of the inbreds, and to identify the heterotic groups. Additive and nonadditive gene actions were important in the control of the inheritance of drought tolerance and striga resistance in the inbreds. General combining ability (GCA) mean squares of grain yield and other traits were larger than those of specific combining ability (SCA), indicating that additive gene action was more important in the inheritance of drought tolerance. The GCA mean squares for striga damage rating at 8 and 10 weeks after planting (WAP) were about six and five times greater than those of the SCA, indicating that additive gene action played a major role in the inheritance of the striga traits. The GGE biplot analysis revealed that TZEI 4 and TZEI 5 were the most promising inbreds in yield performance and stability across the test environments. Two heterotic groups were identified; [TZEI 7, TZEI 19, TZEI 2, TZEI 4] and [TZEI 5, TZEI 3]. Tester TZEI 3 was the closest to the ideal tester. Entry TZEI 7 had the highest GCA effects and TZEI 2 the lowest.

Yield Gains in Extra‐Early Maize Cultivars of Three Breeding Eras under Multiple Environments

“…These results are consistent with the findings of Badu-Apraku et al (2011) and. The presence of significant E × Cultivar and E × Era mean squares for grain yield and most measured traits under multiple stress and non-stress environments indicated differential responses of the genotypes and the need to identify high-yielding and stable cultivars across environments, as reported by Sabaghnia et al (2008); Moghaddam and Pourdad, (2009).…”

“…The presence of significant E × Cultivar and E × Era mean squares for grain yield and most measured traits under multiple stress and non-stress environments indicated differential responses of the genotypes and the need to identify high-yielding and stable cultivars across environments, as reported by Sabaghnia et al (2008); Moghaddam and Pourdad, (2009). This result confirmed the need for extensive testing of cultivars in multiple environments, including location and years before cultivar recommendations are made in the subregion (Badu-Apraku et al, 2011, 2015b.…”

“…Presently, farmers in Striga endemic agro-ecologies of WCA are demanding extra-early and early (90-95 d to maturity) cultivars with combined resistance or tolerance to Striga and drought and are unwilling to adopt maize cultivars that do not possess both adaptation to droughtprone environments and Striga resistance (Badu-Apraku et al, 2013a, 2013b, 2015b. Improvement for drought tolerance has most often resulted in specific adaptation and improved performance under low-N conditions, indicating that tolerance to either stress involves common adaptive mechanism (Bänziger et al, 1999;Badu-Apraku et al, 2011, 2015a. It is therefore becoming increasingly important to adopt a holistic approach to identify genotypes with tolerance to a range of stresses expected in the target environment in WCA instead of compartmentalizing different stresses (Badu-Apraku et al, 2010).…”

Inheritance and combining ability study on drought tolerance and grain yield among early maturing inbred lines of maize (Zea mays L.)

“…The score of leaf senescence (Leaf S) was recorded on the scale from 1 to 10 by dividing the percentage of estimated total dead leaf area by 10 (Bänziger et al, 2000) as 1 = 0-10% dead leaf, 2 = 10-20% dead leaf, 3 = 20-30% dead leaf, 4 = 30-40% dead leaf, 5 = 40-50% dead leaf, 6 = 50-60% dead leaf, 7 = 60-70% dead leaf, 8 = 70-80% dead leaf, 9 = 80-90% dead leaf and 10 = 90-100% dead leaf. Plant height (PHT) and ear height (EHT) were measured from the base of the maize plant to the top of the largest leaf and ear leaf, respectively using measuring tape (cm) (Badu-Apraku et al, 2012). Ears per plant (EPP) was recorded as the total number of ears which developed at least one full grain and divided by the total number of all the plants harvested in the plot (Bänziger et al, 2000).…”

Combining ability of tropical early maize (Zea mays L.) inbred lines for grain yield and resistance to maize streak virus disease

“…This result agrees with those of Vivek et al (2010), Gichuru et al (2011) and Mutengwa et al (2012) who found out that additive gene effects were predominant in the inheritance of resistance to MSVD. High GCA mean square implied that the per se performance of the inbred lines used in this study should be a suitable pointer of the performance of their hybrids (Gethi and Smith, 2004;Badu-Apraku et al, 2011). For grain yield, the ratios for all were less than unity indicating that non-additive effect was more predominant, indicating that heterosis could be exploited from crossing the set of parental lines used in the study.…”