Seedling Cold Tolerance and Yields of Early Seeded Canola.
Chengci Chen, Grant Jackson, Johnna Heser, and Karnes Neill. Montana State Univ, Central Ag Research Center, HC 90 Box 20, Moccasin, MT 59462
Central Montana is characterized with short growing season, shallow soil, and infrequent summer rainfall. Previous studies have shown that early planting date increased canola (Brassica napus) seed yield, but canola cultivars must be able to germinate in cool soil temperatures and stand frost damage in the early spring. Thirty-seven commercial varieties and breeding lines were planted on April 10, 2006 in a field at the Central Agricultural Research Center of Montana State University to determine 1) freezing tolerance of canola seedlings, and 2) biomass and seed yields of different early seeded canola cultivars. Canola seedling samples were taken from the field and placed in the chamber of a refrigerated circulating bath subjecting to different degrees of freezing treatment, and electrolyte leakage was measured after each step of freezing treatment. Above ground biomass was measured 56 days after planting and grain yield was measured when crop reached maturity. Five selected canola cultivars response to freezing treatment similarly. Electrolyte leakage increased sharply from 5% to 60% when temperature dropped from -2 oC to -4 oC. Biomass and grain yield varied greatly among the cultivars. Grain yield ranged from 560 to 1240 kg ha-1 and Oscar was the top yielding cultivar. There was no correlation between the grain yield and the biomass yield measured 56 days after planting. Different seedling emergence rates were also observed among the cultivars.