Effects of water, nitrogen, and competition on growth, yield and yield components of field-grown tepary bean

Tepary bean (Phaseolus acutifolius A. Gray) was grown in Tucson, Arizona during the summer rainy seasons of 1987 and 1988. Effects of water and nitrogen on growth, yield and yield components were evaluated in 1987. In 1988, effects of water and intercrop competition with Sonoran panicgrass (Panicum sonorum Beal) were evaluated. Total shoot biomass, seed yields and pod yields were significantly reduced by lack of applied water in both 1987 and 1988. Seeds pod⁻¹ were unaffected by lack of applied water in both 1987 and 1988 while mean seed weight was significantly reduced for rainfed treatments relative to irrigated treatments in 1987 but not in 1988. In 1987, addition of nitrogen had no significant effect on total shoot biomass, seed yield or yield components. In 1988, intercrop competition significantly reduced total shoot biomass, seed and pod yields of tepary bean. Seeds pod⁻¹ and mean seed weight were not affected by competition.