Influence of Seed Orientation on Bean Seedling Emergence

Observation from an unrelated field bean experiment indicated that certain seed orientations might reduce emergence. Consequently, studies were initiated to determine if orientation variations occur in planting and if these variations influence emergence. Orientation of bean seeds, dropped into both "V" and flat-bottom furrows, were classified and tabulated. In "V" furrows almost all orientations were possible; 36% assumed the "lay-flat" orientation. In the flat-bottom furrow 85% of the beans were in the "lay-flat" position. The influence of 11 different seed orientations on emergence was evaluated in greenhouse studies. With crusted soils seeds planted "hypocotyl end down" produced significantly less emerged seedlings (1% level) and a lower emergence rate. Orientation effects were observed to a lesser degree in noncrusted soils. The adverse influence of "hypocotyl end down" orientations was attributed to seed rotation within the soil. For controlled plantings the "lay-flat" orientation is recommended due to both its high frequency of occurrence and high emergence