US-1136, US-1137, and US-1138 Cowpea Lines for Cover Crop Use

US-1136, US-1137, and US-1138 are new cowpea lines with vigorous, indeterminate growth habits that were released by the Agricultural Research Service of the U.S. Department of Agriculture in 2010 and are recommended for use as a cover crop. Cowpeas are valued as a summer cover crop (Clark, 2007), because they thrive in hot moist environments, grow well in low-fertility soils, and their vigorous growth smothers weeds. They can fix up to 220 kg·ha nitrogen and are an excellent source of nitrogen for fallplanted crops. Resistance of cover crop cultivars to soilborne diseases is necessary to avoid increasing populations of pathogens and plant–parasitic nematodes that induce disease in rotational crops. Many indeterminate cowpea genotypes produce seeds with impermeable seedcoats (hard seeds). The major attributes of lines US-1136, US-1137, and US-1138 have rapid growth, high biomass production, a long vegetative growth period, and southern root knot nematode [Meloidogyne incognita (Chitwood) Kofoid and White] resistance, and they do not produce seeds with impermeable seedcoats.