Seed vigour in Iranian wheat seeds exposed to cold condition.

Cold stress occurring in the seedbed of winter wheat at the end of autumn results in reduced emergence, even of undeteriorated seed lots (which have not been subjected to a long period of storage and have not been kept in bad storage conditions). The purpose of the present study was to determine the ability of different wheat cultivars at emerging at low field temperatures and the usefulness of a number of laboratory tests in predicting relative emergence of undeteriorated seed lots of different wheat cultivars. Due to genotype variability there were different categories of vigour tested through field and laboratory tests. There were no significant correlations between laboratory tests and field emergence. Our results suggest that conventional vigour tests like standard germination and accelerated ageing do not have enough capacity for identifying genotype differences when emerging in cold conditions.