Seed Pretreatments and Their Effects on Field Establishment of Spring-Seeded Gardner Saltbush

Abstract

Gardner saltbush [Atriplex gardneri (Moq.) D. Dietr.] seeds collected from the Red Desert Basin of Wyoming were subjected to pretreatments of scarification (Sc), washing (W), and stratification (St) to alleviate dormancy. Laboratory germination was evaluated. Subsequently, seedling vigor was observed by determining field emergence of similarly pretreated seeds spring planted at 1 irrigated and 2 dryland sites in Wyoming. Effects of 1-cm and 3-cm planting depths on emergence were also evaluated. Seed was pretreated, then dehydrated with minimal impact on seed germination. Field emergence was much less than laboratory germination for all treatments at all sites, indicating that establishment for this species is related to poor seedling vigor as much as to seed dormancy. Moreover, when compared to untreated controls, relative responses to seed pretreatments often differed between laboratory and field trials. In the laboratory Sc = W = St provided the greatest germination, whereas the best seed pretreatment for field establishment was Sc + St. Washing had little effect on enhancing field emergence and appeared to inhibit effects of St in scarified seed. The most effective planting depth varied with climatic/edaphic severity of the site.