Germination of Seed of Three Varieties of Spotted Locoweed

Abstract

Spotted locoweed (Astragalus lentiginosus Dougl.), one of the principal locoweeds of western rangelands, consists of 36 varieties. The objectives of this study included the definition of some of the factors influencing seed germination of the species. Five seed collections were studied; they represented five different geographical and edaphic locations. Three varieties of spotted locoweed were represented by these collections. The seed coat of the varieties studied was impermeable to water. Seed also contained a water-soluble germination inhibitor. Germination was not affected by light. Optimal germination occurred at the temperature regime 7/13 degrees C. However, at -1/4 and 21/27 degrees C, though it was slower, high percentage germination was ultimately achieved. Although salinity inhibited germination, seed from the different sources showed different tolerances to salinity.