Diversity of Maize Kernels from a Breeding Program for Protein Quality: II. Correlatively Expressed Functional Amino Acids

Abstract

Modern maize (Zea mays L.) breeding and selection for large starchy kernels may have contributed to reduced contents of essential amino acids, including lysine, methionine, and cysteine, which represents a serious nutritional problem. We evaluated 1348 maize accessions classified into 13 populations and derived from crossing exotic, high-quality maize landraces with Corn Belt stiff-and non-stiff-stalk heterotic groups. We used multivariate statistical analyses methods and validated partial least squares regression and structural equation models to study the homeostasis of these amino acids in relation to other phytochemicals in the maize kernel. New insights into the relative importance of several phytochemicals were derived from structural equation modeling, indicating that biochemical and physical constituents had negative impacts on amino acid contents regardless of heterotic group or endosperm texture and that mineral nutrients had positive effects; whereas, color space descriptors had mixed effects depending on heterotic group and endosperm texture. It was possible to develop quality protein germplasm with large lysine (4.2 g kg -1 dry mass) content and opaque endosperm that resembles translucent endosperm, while the conversion from opaque to translucent endosperm was associated with minimal loss of lysine. Accessions derived from DKXL370-S11, DXKL370-N11a-N20, and 'Nokomis Gold' populations were identified as sources with high and stable contents of protein and all three amino acids, having either opaque or translucent endosperm textures.

Diversity of Maize Kernels from a Breeding Program for Protein Quality III: Ionome Profiling

“…Earlier Jaradat and Goldstein [25,26] identified sources of variation of single and multiple quality traits, determined the level of genetic diversity present in a large maize germplasm, and quantified phenotypic variation that may be useful for developing high-quality maize cultivars. Concerns are rising over the declining density of micronutrients, especially Fe and Zn, and some macronutrients (e.g., Ca and Mg) in grains of staple food and feed crops.…”

“…The R 2 values for protein, amino acids, and starch (>0.96) were logically larger than for oil (0.38), presumably due to their larger genetic components [26]. Others have found that densities of some nutrients (e.g., Mg, S, Fe and Zn) are correlated with grain protein content (GPC) [15].…”

A Nutritional analysis of selected heterotic hybrids of Zea mays L.

“…Breeders should plan their breeding strategy for developing new hybrids depending on the future demand and market requirements (Dagade et al, 2015). The nutritional quality of maize can be improved by selecting the essential amino acids through selection and breeding (Jaradat and Goldstein, 2014). Maize kernels with high methionine and lysine concentrations are important in poultry feed (Moore et al, 2008;Adeyemo, 2012).…”