Identifying and using value -added traits in GEM accessions (Latin American maize) to improve Corn-Belt dent corn

摘要

The goal of this research was to identify exotic germplasm used in the U.S. Germplasm Enhancement of Maize Project (GEM) for its potential to enhance value-added traits in Corn-Belt dent corn. GEM is the US successor to the Latin American Maize Project (LAMP) which was launched in 1987 by the U.S. Department of Agriculture, Agriculture Research Service.;LAMP evaluated 12,000 accessions grown in 70 countries in the United States and Latin America. Screening was done on the basis of yield potential and agronomic characteristics. Two hundred sixty-eight of these accessions were selected as potential source of high yields, then fifty-one chosen to initiate GEM.;Before value-added traits could be evaluated, methods for wet milling corn into finished products was required. Therefore, we refined and compared methods for laboratory (100 g and 1 Kg) and pilot-plant (10 Kg) wet milling. Rankings for starch yields and recoveries of one waxy and three normal yellow dent hybrids, having very different physical and compositional properties, were the same for all three procedures. Forty-nine GEM accessions, two commercial corn hybrids, and two inbreds were evaluated for their compositional and physical properties, and wet-milling characteristics.;The thermal, pasting, and gelling properties of the starches recovered from the accessions varied widely. Starches recovered from the accessions generally had higher onset and peak gelatinization temperatures, and peak height indices and heats of gelatinization were lower.;Ten selected accessions (GEM) were crossed with B73 and Mo17 inbreds and evaluated for compositional, physical, and wet-milling properties to gain insight about the potential to use GEM material to develop hybrids with unique traits. Crossing the GEM accessions with either inbred resulted in grain with greater protein and less starch than either parent.;The thermal properties of the starches recovered from the GEM crosses were also examined to gain insight about starch properties of exotic breeding crosses and hybrids. The thermal properties of starches recovered from the GEM x B73 and GEM x Mo17 crosses had much narrow ranges than did the starches recovered from the GEM accessions. (Abstract shortened by UMI.).