Genetic Analysis of Early White Quality Protein Maize Inbreds and Derived Hybrids under Low-Nitrogen and Combined Drought and Heat Stress Environments

Abstract

An increase in the average global temperature and drought is anticipated in sub-Saharan Africa (SSA) as a result of climate change. Therefore, early white quality protein maize (QPM) hybrids with tolerance to combined drought and heat stress (CDHS) as well as low soil nitrogen (low-nitrogen) have the potential to mitigate the adverse effects of climate change. Ninety-six early QPM hybrids and four checks were evaluated in Nigeria for two years under CDHS, low-nitrogen, and in optimal environments. The objectives of this study were to determine the gene action conditioning grain yield, assess the performance of the early QPM inbred lines and identify high yielding and stable QPM hybrids under CDHS, low-nitrogen and optimal environment conditions. There was preponderance of the non-additive gene action over the additive in the inheritance of grain yield under CDHS environment conditions, while additive gene action was more important for grain yield in a low-nitrogen environment. TZEQI 6 was confirmed as an inbred tester under low N while TZEQI 113 × TZEQI 6 was identified as a single-cross tester under low-nitrogen environments. Plant and ear aspects were the primary contributors to grain yield under CDHS and low-nitrogen environments. TZEQI 6 × TZEQI 228 and the check TZEQI 39 × TZEQI 44 were the highest yielding under each stress environment and across environments. Hybrid TZEQI 210 × TZEQI 188 was the most stable across environments and should be tested on-farm and commercialized in SSA.

Performance and Stability Analysis of Extra-early Maturing Provitamin A Maize Hybrids under Drought Stress and Well-Watered Conditions

“…These results provide a basis for rapid genetic gains from selection and identification of hybrids with desirable traits for each research condition [22,23]. Significant environment mean squares observed for anthesis-silking interval and husk cover under managed drought indicated that the difference in environmental conditions that prevailed in the two years of evaluation affected these trait [24]. A similar trend of results was observed for grain yield, anthesis-silking interval, plant aspect, and ears per plant under well-watered conditions.…”

Selection of extra-early white quality protein maize (Zea mays L.) inbred lines for drought and low soil nitrogen resilient hybrid production

“…Maize is an important staple crop for about half of the human population in sub-Saharan Africa (SSA). Due to its economic importance, it is anticipated to become the most important cereal crop by 2025 across the world (FAOSTAT, 2017;Bhadmus et al, 2021). However, factors such as drought and low soil N severely hamper its productivity and production across the sub-region, thereby increasing food and nutritional insecurity (Badu-Apraku et al, 2011;Annor and Badu-Apraku, 2016;Kountche et al, 2019).…”

“…However, the levels of lysine and tryptophan are inadequate. This makes children fed on non-quality protein maize (non-QPM) without other dietary protein sources suffer growth deformities such as kwashiorkor due to malnutrition (Olakojo et al, 2007;Upadhyay et al, 2009;Mbuya et al, 2011;Annor et al, 2019;Bhadmus et al, 2021). Quality protein maize, however, can provide 73% of the protein needs of human beings and contains nearly twice the quantity of tryptophan and lysine in the non-QPM endosperm (Annor et al, 2019;Bhadmus et al, 2021).…”

Variation in the morphology and effector profiles of Exserohilum turcicum isolates associated with the Northern Corn Leaf Blight of maize in Nigeria

“…Over 4.5 billion people in developing countries obtain ~ 30% of their calories from maize. In sub-Saharan Africa (SSA), maize is the most widely grown and consumed staple food with an estimated 50% of the populace depending on maize as the primary staple [ 1 , 2 ]. Maize ranks first in the world cereal production (1.15 billion tons) with the United States of America as the largest producer (~ 50% of the total production) [ 3 ].…”