Germination of two seed types from three dalea species

Dalea species are legumes that often are included in seed mixtures used for prairie restorations. Three Dalea species (D. foliosa, D. candida, and D. purpurea) exhibit two different types of seeds: plump (well-rounded larger) and dented (wrinkled smaller) seeds. Differences in germination and viability of these two types of seeds have not been reported. Our objectives were to compare seed mass, germination and viability between these types of seeds for three Illinois Dalea species. Fruits were collected for D. foliosa from 19982001 (Will County) and for D. candida and D. purpurea from 20012003 (Kankakee, Tazewell and Will Counties). For each species, seed mass, germination and viability were determined per seed type (plump or dented). Seed mass was significantly higher for plump than dented seeds for all three species. For D. foliosa and D. candida, germination of dented seed exceeded that of plump seed in some years. For D. purpurea, germination was significantly greater for plump seeds in both years. For ungerminated seeds of D. foliosa, only the plump seeds were viable, whereas for D. candida and D. purpurea, both seed types were viable. A comparison of seed germination among all three species when collected in the same county and year showed lower germination for D. foliosa than for D. candida and D. purpurea. In summary, seed types play a significant role in germination of these three species, and D. foliosa has lower germination than D. candida or D. purpurea.