Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2012
Publication Date: 4/25/2013
Publication URL: http://handle.nal.usda.gov/10113/56457
Citation: Jaradat, A.A., Goldstein, W. 2013. Diversity of maize kernels from a breeding program for protein quality: I. Physical, biochemical, nutrient, and color traits. Crop Science. 53:956-976. Interpretive Summary: Farmers and the food and feed industries will continue to demand high-yielding maize varieties with improved nutritional and industrial qualities. It has been long recognized that breeding maize varieties with high levels of protein, oil, starch, and essential amino acid contents, while maintaining high grain yield, is a challenge. We evaluated 1,348 maize collections belonging to 13 populations from a breeding program for high protein content. These populations were comprised of germplasm from stiff and non-stiff stalk groups at different stages of inbreeding and different seed qualities. We measured 31 physical, biochemical, nutrients, and color traits on 10 seeds from each collection. The objective was to find out how much variation in these quality traits is available for selection and how these traits are interrelated. We developed a visual procedure to help explain the relationships between and within physical and quality traits. In addition, we identified which populations have larger variation for specific traits. The information will help researchers choose the appropriate accessions for breeding and selection and to meet quality and yield requirements of farmers and industry.
Technical Abstract: It is a challenge to breed maize (Zea mayz L.) varieties with enhanced levels of protein, oil, starch and essential amino acid contents while maintaining competitive agronomic capability. We employed multivariate statistical procedures to quantify diversity and its components for 31 physical, biochemical, nutrients and color traits of 1,348 accessions from 13 maize populations. These populations were comprised of germplasm from stiff and non-stiff stalk heterotic groups at different stages of inbreeding, and with opaque or translucent endosperm. Cluster, principal components and variance components analyses resulted in separating populations and traits into statistically different groups and helped to identify physical and color traits that may be useful for selecting accessions with high protein, amino acid, oil and nutrient contents. We identified correlative relationships between groups of biochemical and nutrient traits linked to certain populations, physical or kernel color traits. Diversity analyses revealed variable relationships between and within total diversity and its components depending on kernel physical, biochemical, nutrient and color traits. Sources of variation in, and amount of variation attributed to total diversity for each of these traits were identified and quantified. Populations and accessions within populations were identified as sources of variation for multiple kernel quality traits that can be used in developing high-quality maize varieties.