The "stress avoidance" hypothesis suggests that larger-seeded crops are better able to survive multiple stresses, included allelopathic effects of incorporated green manures, better than smaller-seeded species. Many weed species have seeds that are very small compared to those of some crops they infest, e.g., from top left, yellow foxtail, wild mustard, hairy galinsoga, compared to squash, pea and green bean, right.
photo: Erin Haramoto