Enhanced Germination and Emergence of Dormant Wild Mustard (Sinapsis arvensis) Seed by Two Substituted Phthalimides

Abstract

Applications of the substituted phthalimide growth regulators AC-94377 [1-(3-chlorophthalimido)cyclohexanecarboximide] and AC-99524 [1-tetrahydrophthalimido-cyclohexanecarboximide] to the soil surface stimulated germination and emergence of dormant wild mustard seed (Sinapsis arvensisL. ♯4SINAR) shallowly planted in soil in greenhouse experiments. Surface applications of AC-94377 enhanced the germination and emergence of dormant wild mustard seed planted 0.6 cm deep in soil from nine locations as the rates were raised from 0.4 to 3.7 kg ai/ha. Surface application of AC-94377 increased emergence rates and also extended the period of wild mustard emergence. Increasing quantities of wheat (Triticum aestivumL.) straw on the soil surface reduced the effect of surface-applied AC-94377 on shallowly buried dormant wild mustard seed. When dormant wild mustard seed were buried 1.3, 2.5, or 3.8 cm deep, surface applications of AC-94377 also stimulated greater emergence than the dormant controls from these depths, strongly suggesting that the compound moved from the surface to the depth of planting.