Agronomic and Kernel Compositional Traits of Blue Maize Landraces from the Southwestern United States

Diverse landraces of maize have been cultivated for centuries in the southwestern United States and northern Mexico primarily for human food consumption. A striking feature of these landraces is the wide array of kernel colors displayed. Traditional cultivation is declining, but blue maize has received increasing commercial interest due to rising consumer demand for unique food products with health benefits and special culinary uses. We evaluated grain yield, agronomic and morphological traits, and analyzed the kernel biochemical composition of five blue and one purple landraces representative of diversity in the Southwest. These were compared with selected open-pollinated populations derived from Southwest and Corn Belt blue maize at several New Mexico locations in 2012 and 2013. Kernel amino acids, oil, protein, starch, fatty acids, crude fiber, ash and anthocyanin pigment contents were determined. Grain yield across all locations, years, and accessions averaged 2.11 Mg ha(-1). Navajo Blue and Hopi Blue were the highest and lowest yielding accessions, respectively. The majority of southwestern landraces displayed higher oil content, and two displayed higher protein content, than the Corn Belt Dent variety. Little variation in total amino acid content was observed. Several southwestern floury accessions displayed similar to 10% greater lysine and methionine than did dent or flint genotypes. Considerable variation for plant, ear, and kernel compositional traits within and across southwestern landraces was consistent with the presence of racial admixtures. The health-promoting properties of anthocyanin-rich landraces contribute to sound dietary nutrition and human health. This study further illustrates the diversity of southwestern maize and supports the rationale for their continued conservation through sustained cultivation and utilization. Directed selection to improve grain yield and uniformity will be necessary to enhance their potential for commercial production.