INCREASING WINTER SURVIVAL OF DORMOAT SEEDS BY A TREATMENT INDUCING SECONDARY DORMANCY

Abstract

Treatment of partially after-ripened dormoat (Avena sativa L. × A. fatua L.) seeds by soaking in water and incubation in an enclosed humid atmosphere for 2 wk induces secondary dormancy and increases the winter survival of field plantings. Immediately after treatment, the seeds are highly dormant when incubated on moist filter paper in petri plates at 20 C, but there is a slight stimulation of germination at low incubation temperature (7 C) and during incubation in soil. The germination response to these two factors increases with time, and reaches 100% when tested after 6 wk dry storage. Germination in petri dishes at 20 C increases slowly with storage time, attaining 57% or less after 12 wk. Germination is increased by decreasing water volume during test, to a level similar to that obtained by incubation of seeds in soil. Survival of dormoat seeds through the winter of 1970–71 was increased an average of threefold by the treatment, to a maximum of 40% in several strains. There is no increase in seed cold hardiness due to the treatment. The treatment increases the dormancy level of seeds before planting, and seed with induced secondary dormancy is only slightly stimulated to germinate by low incubation temperatures. Both these factors increase the number of un-germinated seeds entering winter.