Winter Survival and Spring Forage Yield of Winter Rye Varieties in Subarctic Alaska as Influenced by Date of Planting 1

Three dates of planting during late summer were compared in four successive field tests for effects on winter survival and on subsequent spring forage yields of several varieties of winter rye ( Secale cereale L.) near Palmer in south‐central Alaska. Amount of seedling growth achieved before termination of the growing season differed among years and was related to September temperatures. When winterkill was moderate to severe, survival of seedlings was better with planting 16 to 23 Aug. than earlier (9 to 12 Aug.) or later (27 Aug. to 8 Sept.). Earliest dates of planting, however, always resulted in earliest forage growth and highest yields the following spring. Yields were progressively smaller with successively later dates of planting. In one test, only very winterhardy varieties were included and all survived the relatively mild winter without apparent injury. In the other three tests, winter stress resulted in disparate survival of rye cultivars. Varieties that grew most rapidly as seedlings sustained greatest winterkill. ‘Antelope,’ ‘Caribou,’ ‘Emerald,’ ‘Pierre,’ and ‘Sitnikoff’ were superior to ‘Elk,’ ‘Sangaste,’ and ‘Toivo’ in winter survival and, hence, in subsequent forage yield. Crude protein content of harvested forage was consistently high (20 to 26%) and was not influenced by varieties or planting dates.