GROWTH, DEVELOPMENT, AND COLD TOLERANCE OF FALL-ACCLIMATED CEREAL-GRAINS

Areas of adaptation of winter cereals are determined primarily by each species'' ability to tolerate cold. These differences in cold hardiness were investigated during fall acclimation of spring and winter cultivars of rye (Secale cereale L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oats (Avena sativa L.). Material for these studies was acclimated under field conditions in the fall of 1972, 1975 and/or 1977 at Saskatoon, Saskatchewan, Canada. Spring cultivars occasionally demonstrated a limited ability to acclimate to cold. The maximum cold hardiness attained by the hardiest cultivar of each species when fully acclimated was -13, -15, -21 and -30.degree. C for oats, barley, wheat and rye, respectively. During acclimation, crown and shoot dry weight increased and days to head and percent crown water decreased for most of the cultivars considered. In both spring and winter cultivars, dry matter accumulated at a rate which would suggest that energy production during the acclimation period was not a limiting factor for cold acclimation under normal fall field conditions. Percent crown water was closely associated with cold hardiness for comparisons within species. There were differences in the responses among species indicating that acclimation to cold was more complex than simply the regulation of tissue water content.