Variation amongst Canadian six-row spring barley cultivars for germinationand emergence characteristics in controlled environments and in the field

Information is lacking concerning the extent of variability in Canadian six -row barley cultivars for differences in potential field germination vigour and other germination characteristics, and the extent to which these trait s can be predicted from laboratory tests. This study was conducted to evalu ate the extent to which a genetically diverse range of Western Canadian six -row barley cultivars differ in germination resistance and early seedling v igour or emergence rate under controlled environments and in the field, ove r a range of temperature stress conditions. Vigour was assessed by measurin g germination rate, emergence rate, and dry weight accumulation in young se edlings, in the growth cabinet and in the field. Cultivars studied were sel ected to represent a wide range of genetic diversity typical of Canadian br eeding programs of the early 1980s. Growth cabinet assays were conducted at six temperatures from 2.5 to 20 degrees C. Field trials were conducted usi ng the same cultivars seeded at three dates per site in 2 yr, to assess cul tivar emergence rates and seedling dry weight accumulation over a range of seedbed temperatures, using two seed sources from cultivar increases each g rown in different years. Cultivars differed significantly for germination resistance in the growth c abinet and the performance of cultivars was relatively consistent across as say temperatures and for the two different seed sources. Differences among cultivars in growth for seedling dry weight were also consistent across tem peratures, but cultivar performance for seedling dry weight accumulation wa s not significantly correlated with germination resistance in the cabinet t est. In field trials, days to emergence were highly and significant ly corr elated with germination resistance determined in the growth cabinet. Germin ation resistance was less strongly correlated with dry weight accumulation in the field at 5 wk. Across cultivars, seedling dry weight estimates in th e field were significantly correlated with seedling dry weights assayed in the growth cabinet. Results from this study confirm that genetic variation in potential germination rate and seedling vigour in the field can be ident ified in six-row barley using the germination resistance assay in the growt h cabinet. Germination resistance identified more cultivar differences than were found for the seedling dry weight accumulation tests, which were char acterized by high coefficients of variation and low correlation between gro wth cabinet and field.