The Germination Stimulant AC94377 Reduces Seed Survival of Wild Mustard (Sinapis Arvensis)

Abstract

Annual application of AC-94377 at 3.4 kg ha−1in the field reduced survival of shallowly buried (1.25 cm deep), undisturbed wild mustard seed compared to untreated check seed in two 4-yr-long trials. By the second fall, greater than twofold more untreated check seed survived as did AC-94377-treated seed. Moreover, no AC-94377-treated seed survived beyond year three following treatment in fall alone or fall plus spring in each of 3 yr. In contrast, 25% of untreated check seed survived into the fall of year four. AC-94377 applied in spring alone, fall alone, or both spring and fall for each of 4 yr progressively reduced seed survival. Seed survival expressed as a percent of the initial number of seed buried was best modeled as a negative exponential function of time in years. In the greenhouse, more wild mustard seed on the soil surface established after AC-94377 treatment at 3.4 kg ha−1when enclosed in large seed packets (5 by 12 cm), like those used in the field, than when in small seed packets (5 by 6.25 cm), whether or not the packets contained soil. When soil was added to either sized seed packet, fewer seed survived compared to seed not in seed packets or seed in packets without soil. Thus, it is likely that the field seed survival study underestimated effectiveness of AC-94377 to reduce wild mustard seed survival.