Slow germination and poor seedling vigor limit stand establishment of forage Brassica spp. Soil temperature is a major factor influencing both processes. Temperature effects on germination of 11 forage brassica cultivars, comprised of three species plus one hybrid, were studied in an incubator. The species and cultivars tested were turnip (B. rapa L.): Civastro-R, Polaris, Purple Top, Stubble, and Forage Star; rape (B. napus L.): Emerald, Fodder, and Dwarf Essex; kale (B. oleracea L.): Premier, and Marls Kestral; and the turnip × Chinese cabbage hybrid [B. rapa L. × B. pekinensis (Lovr.) Rupr.]: Tyfon. Germination studies were conducted in the dark at 10 constant temperatures (0,2,5,10,15,20,30,35,40, and 50°C). Number of seeds germinated were counted on Day 4 and 14 after planting. Cultivars differed significantly (P ≤ 0.001) for percentage germination on both day 4 and 14 at all temperature treatments except 2 and 40°C. Under the cool temperatures (5 and 10°C), Civastro-R, Polaris, Purple Top, and Stubble were the earliest germinating cultivars. At the 40°C temperature regime, Marls Kestral initiated germination earlier than that of the other cultivars, but total germination was highest for Polaris. The cultivars Civastro-R, Polaris, Purple Top, and Stubble could serve as potential parents of a new cultivar because of their ability to germinate rapidly over a wide range of temperatures.
(Part of a thesis submitted by the senior author in partial fulfillment of a M.S. Degree at Univ. Nevada, Reno).