Effect of Some Seed Characteristics on Mechanically Induced Seedcoat Damage in Navy Beans (Phaseolus vulgaris L.)

Abstract

AbstractNavy bean seeds were evaluated for their response to mechanical abuse. Seed of all lines was hand threshed and equilibrated to a constant moisture content prior to damaging.Highly significant differences were found among lines in their reaction to seedcoat cracking. Seed weight, shape, density and seedcoat anatomy were examined as components contributing to seedcoat damage. Seedcoat cracking increased as the seed weight increased. Normal within‐line weight differences were small and self‐compensating, but between lines weight variation had a highly significant effect on cracking. Cracking also increased as the shape became more nonspherical. Increased seed density improved seedcoat tolerance to mechanical abuse but caused a nonsignificant increase in cotyledon splitting. Tolerant bean lines generally had a thinner parenchymatous layer underlying the osteosclerids. There was no difference in the thickness of the osteosclerid and macrosclerid layers between tolerant and susceptible lines.