Gains in Genetic Enhancement of Early Maturing Maize Hybrids Developed during Three Breeding Periods under Striga-Infested and Striga-Free Environments

Striga hermonthicais a major maize production constraint in West and Central Africa (WCA). Fifty-four early maturing maize hybrids of three breeding periods: 2008-2011, 2012-2013, 2014-2015, were evaluated underStriga-infested and non-infested environments in WCA. The study aimed at assessing genetic improvement in grain yield of the hybrids, identifying traits associated with yield gain during the breeding periods, and grain yield and stability of the hybrids inStrigainfested and non-infested environments. Annual increase in grain yield of 101 kg ha(-1)(4.82 %) and 61 kg ha(-1)(1.24%) were recorded inStriga-infested and non-infested environments, respectively. The gains in grain yield from period 1 to period 3 underStriga-infested environments were associated with reduced anthesis-silking interval, reducedStrigadamage, number of emergedStrigaplants, improved ear aspect, and increased ears per plant. Ear aspect, ears per plant, andStrigadamage at 8 and 10 weeks after planting (WAP) were significantly correlated with yield inStriga-infested environments, whereas ears per plant and plant and ear aspects had significant correlations with yield in non-infested environments. Hybrids TZdEI 352 x TZEI 355, TZdEI 378 x TZdEI 173, and TZdEI 173 x TZdEI 352 were outstanding in grain yield and stability inStriga-infested environments, whereas TZEI 326 x TZdEI 352, TZEI 495 x ENT 13, and TZdEI 268 x TZdEI 131 were superior in non-stress environments. These hybrids should be further tested extensively and commercialized. Significant genetic gains have been made in breeding for resistance toStriga hermonthicain early maturing maize hybrids.