Protein quality and quantity of quality protein maize (QPM) and non‐QPM hybrids under optimal and low nitrogen conditions

Abstract

Background and objectives Quality protein maize (QPM) nutritional quality involves high total protein content but reduced zein accumulation in maize endosperm, leading to increased non‐zein proteins, hence higher levels of essential amino acids such as lysine and tryptophan. The aim of this study was to assess the effect of low nitrogen (N) conditions in one location, and optimum conditions in three locations, on zein proteins in 10 QPM hybrids developed by the International Maize and Wheat Improvement Centre (CIMMYT) compared to two non‐QPM checks. Findings With a few exceptions, total protein content, and γ‐ and α‐zein peak areas were significantly reduced under low N compared to optimal conditions, while β‐zein increased. Non‐QPM hybrids had higher protein content than QPM hybrids, and QPM hybrids had higher γ‐zein than non‐QPM in all environments. Higher α‐zein values than other zein types were observed in non‐QPM than in QPM genotypes in all environments. Significance and novelty Low N significantly reduced protein content and all the zein fractions except for β‐zeins, which were increased. The advantages of a decrease in zein fractions in QPM under low N conditions were offset by a large decrease in grain protein content.

Genome-wide association studies of grain yield and quality traits under optimum and low-nitrogen stress in tropical maize (Zea mays L.)

“…According to Jahangirlou et al (2021) and Simić et al (2020), high N conditions are associated with higher protein content and yield. On the other hand, low N substantially decreases protein concentration and all zein fractions apart from β-zeins, according to research conducted in Zimbabwe by Shawa et al (2021). The impact of soil nutrient management on oil content was significant in the study of Ray et al (2019).…”

In vitro determination of the protein quality of maize varieties cultivated in Malawi using the INFOGEST digestion method

“…The performance of QPM varieties under different environments has been tested in several studies, with evidence of some common maize hybrids outperforming QPM under certain conditions [ 15 ]. Lower protein and lysine contents have also been reported for QPM grown under low nitrogen conditions [ 30 ], which is typical for small holder farming systems in SSA.…”

Unravelling the genetic architecture of grain quality traits under optimum and low-nitrogen stress conditions using tropical maize (Zea mays L.) germplasm

“…According to Jahangirlou et al (2021) and Simić et al (2020), high N conditions are associated with higher protein content and yield. On the other hand, low N substantially decreases protein concentration and all zein fractions apart from β-zeins, according to research conducted in Zimbabwe by Shawa et al (2021). The impact of soil nutrient management on oil content was signi cant in the study of Ray et al (2019).…”