Identifying Winter Pea Genotypes That Maximize Grain, Forage, and Cover Crop Potential in the Southeast USA.

Winter pea (Pisum sativum L.) has the potential for use as a grain, forage, and cover crop by organic producers in the Southeast USA. A regional screen of winter pea germplasm has not occurred in this region. Two experiments were conducted to evaluate 19 winter pea genotypes for use as grain, forage, and cover crops in the Southeast USA. The first study evaluated the grain cropping potential of winter pea in monoculture and in mixture with early, medium, and late maturing wheat varieties. This experiment was conducted over two growing seasons from 2014-2016 in Clayton, Kinston, and Salisbury, NC. Pea genotypes were visually evaluated for cold tolerance, disease susceptibility, and maturity. Grain yield was obtained using a research combine. One pea genotype had significant cold damage at all environments resulting in poor winter survival. All other pea genotypes experienced minimal cold damage. Heavy disease pressure at one environment from Sclerotinia sclerotiorum resulted in very low pea grain yields across all pea genotypes during both growing seasons. Pea genotype affected pea grain yield but growth in monoculture or mixture with wheat did not. Several pea genotypes consistently provided the highest grain yield across environments and the grain yield of these genotypes was substantially higher than the grain yield of the variety currently available in North Carolina, revealing that breeding efforts focused on increasing pea grain yield may have a large impact for producers in the Southeast USA.  The highest pea grain yields obtained in these environments are still low compared to pea grain yields achieved in other USA regions. The second study evaluated the forage and cover crop potential of winter pea in monoculture and in mixture with barley, oats, and wheat. This study was employed from 2015-2016 in Beltsville, MD, Clayton, NC, and Kinston, NC. Each monoculture pea genotype was harvested four times to assess forage and cover crop quality over time. The mixture plots were harvested as the small grain hit soft dough stage. Dry biomass, forage, and cover crop quality were collected from each pea genotype in monoculture and in mixture. Large differences in pea biomass were observed across pea genotypes, with pea biomass in excess of 6,700 kg ha^-1 being achieved for the high biomass producing pea genotypes when grown in monoculture in Clayton and Kinston, NC. At one environment, monoculture pea biomass production was greater than pea biomass production in mixture with small grains, however at another environment with heavy disease pressure, pea biomass production was similar whether produced in monoculture or in mixture with small grains indicating that growth in mixture may help pea biomass production under heavy disease pressure. Results will catalyze variety release of regionally adapted winter pea genotypes for different end uses.