Genetic studies of extra‐early provitamin‐A maize inbred lines and their hybrids in multiple environments

Abstract

Vitamin A deficiency, drought, low soil nitrogen (low-N), and Striga hermonthica parasitism of maize (Zea mays L.) cause malnutrition and food insecurity in sub-Saharan Africa. The objectives of this study were to determine combining abilities of extra-early provitamin A (PVA) lines, classify them into heterotic groups (HGs), identify testers, and determine yield stability of hybrids under contrasting environments in two trials. In Trial 1, 190 F 1 hybrids plus six checks were tested under Strigainfested, drought, and stress-free environments in Nigeria from 2015-2017. In Trial 2, 35 extra-early yellow hybrids were evaluated under low-N, Striga-infested, and stress-free environments in 2018. TZEEIOR 202 and TZEEIOR 205 had PVA concentrations of 23.98 and 22.56 μg g −1 . TZEEIOR 197 × TZEEIOR 205 (20.1 μg g −1 ) and TZEEIOR 202 × TZEEIOR 205 (22.7 μg g −1 ) contained about double the PVA level of the commercial check, TZEEI 58 × TZEE-Y Pop STR C5 (11.4 μg g −1 ). Both general (GCA) and specific (SCA) combining ability variances were significant for most agronomic traits, although GCA was larger than SCA effects, indicating GCA effects primarily controlled the inheritance of those traits. TZEEIOR 97 and TZEEIOR 197

Combining ability of extra‐early biofortified maize inbreds under Striga infestation and low soil nitrogen

“…(2014), and the provitamin A concentrations of the extra‐early PVA hybrids TZEEIOR 197 × TZEEIOR 205 (20.1 µg −1 ) and TZEEIOR 202 × TZEEIOR 205 (22.7 µg g −1 ) reported by Badu‐Apraku et al. (2019), indicating the possibility of further improving the provitamin A levels of the extra‐early PVA‐QPM hybrids developed in this study.…”

“…The per se provitamin A contents of all the 15 extraearly PVA-QPM hybrids selected for provitamin A, lysine, and tryptophan analyses in this study were higher than the provitamin A level of the hybrid with the highest provitamin A content reported by Halilu, Ado, Aba, and Usman (2016) but lower than the provitamin A levels of the best 11 hybrids selected by Suwarno et al (2014), and the provitamin A concentrations of the extra-early PVA hybrids TZEEIOR 197 × TZEEIOR 205 (20.1 µg −1 ) and TZEEIOR 202 × TZEEIOR 205 (22.7 µg g −1 ) reported by Badu-Apraku et al (2019), indicating the possibility of further improving the provitamin A levels of the extra-early PVA-QPM hybrids developed in this study.…”

Genetics of extra‐early‐maturing yellow and orange quality protein maize inbreds and derived hybrids under low soil nitrogen and Striga infestation

“…While Ertiro et al (2017), Obeng-Bio et al (2019) and Oyekale et al (2020) reported the inheritance of grain yield under LN to be largely influenced by additive gene action, Badu-Apraku et al (2016), Mafouasson et al (2017) and Annor et al (2019) reported prominence of non-additive genes. Under Striga, Badu-Apraku et al (2020) and Oyekale et al (2020) established that additive gene effects played a greater role in the inheritance of grain yield, Striga damage syndrome rating and Striga emergence while Badu-Apraku et al (2016) documented superiority of non-additive gene effects. Maternal effects were reported to influence the inheritance of grain yield and few traits under LN, Striga and HN conditions by Oyekale et al (2020) while Ifie et al (2015) reported non-significant maternal effects under similar growing conditions.…”

“…Under Striga , Badu‐Apraku et al. (2020) and Oyekale et al. (2020) established that additive gene effects played a greater role in the inheritance of grain yield, Striga damage syndrome rating, and Striga emergence, whereas Badu‐Apraku et al.…”

“…Although Ertiro et al (2017), Obeng-Bio et al (2019), and Oyekale, Badu-Apraku, and Adetimirin (2020) reported the inheritance of grain yield under LN to be largely influenced by additive gene action, Badu-Apraku et al (2016), Mafouasson et al (2017), and Annor, Badu-Apraku, Nyadanu, Akromah, and Fakorede (2019) reported prominence of nonadditive genes. Under Striga, Badu-Apraku et al (2020) and Oyekale et al (2020) established that additive gene effects played a greater role in the inheritance of grain yield, Striga damage syndrome rating, and Striga emergence, whereas Badu-Apraku et al (2016) documented superiority of nonadditive gene effects. Maternal effects were…”