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

Abstract

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 traits can be predicted from laboratory tests. This study was conducted to evaluate the extent to which a genetically diverse range of Western Canadian six-row barley cultivars differ in germination resistance and early seedling vigour or emergence rate under controlled environments and in the field, over a range of temperature stress conditions. Vigour was assessed by measuring germination rate, emergence rate, and dry weight accumulation in young seedlings, in the growth cabinet and in the field. Cultivars studied were selected to represent a wide range of genetic diversity typical of Canadian breeding programs of the early 1980s. Growth cabinet assays were conducted at six temperatures from 2.5 to 20 °C. Field trials were conducted using the same cultivars seeded at three dates per site in 2 yr, to assess cultivar emergence rates and seedling dry weight accumulation over a range of seedbed temperatures, using two seed sources from cultivar increases each grown in different years.Cultivars differed significantly for germination resistance in the growth cabinet, and the performance of cultivars was relatively consistent across assay temperatures and for the two different seed sources. Differences among cultivars in growth for seedling dry weight were also consistent across temperatures, but cultivar performance for seedling dry weight accumulation was not significantly correlated with germination resistance in the cabinet test. In field trials, days to emergence were highly and significantly correlated with germination resistance determined in the growth cabinet. Germination resistance was less strongly correlated with dry weight accumulation in the field at 5 wk. Across cultivars, seedling dry weight estimates in the 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 identified in six-row barley using the germination resistance assay in the growth cabinet. Germination resistance identified more cultivar differences than were found for the seedling dry weight accumulation tests, which were characterized by high coefficients of variation and low correlation between growth cabinet and field. Key words: Temperature, field seedling vigour, barley cultivars, prediction tests