Seed Size and Planting Depth Effects on Emergence and Yield of Pinto Bean

Abstract

Seed size and planting depth affect plant performance of many crop species. Growers claim that large pinto bean (Phaseolus vulgaris L.) seeds emerge faster and produce higher seed yields than small seeds. A study was conducted during 1986 and 1987 on Billings silty clay loam soil (fine-silty, mixed [calcareous], mesic Typic Torrifluvents) at the Colorado State University Fruita Research Center to investigate the effects of seed size class (small, medium, and large), representing 30, 40, and 30% of the original bulk sample by weight, respectively, and a check; and planting depth (1-, 2-, and 3-in.) and their interaction on seedling emergence and yield of pinto bean. No seed size × planting depth interactions occurred. Seed size effects varied. Seedling emergence of small seeds in 1987 was greater than large and medium seeds. The plant stand from small seeds in 1986 was lower than large and check seeds. Plants grown from large and medium seeds yielded more than small seeds in 1986. Planting seeds at a 3-in. depth slowed seedling emergence and reduced plant stand both years, and lowered yield in 1987. These data suggest that an uneconomical, high cleanout percentage during seed conditioning would be necessary to obtain large seeds and the improved performance of large seeds would not be predictably advantageous. Currently recommended commercial seed conditioning practices to size pinto bean seed lots are probably adequate.