Predicting potential field seedling vigour of Canadian six-row barley cultivars

Abstract

Rapid techniques for predicting the field vigour potential of barley seed samples would be very useful for seed-testing laboratories and barley breeders. The objective of this study was to compare two faster laboratory seed-testing methods, tetrazolium chloride reduction (TZ) and carbon dioxide evolution rate (CDE), with the standard, but slow and costly germination resistance (GR) test, for ability to identify cultivar differences in vigour and their relationship to vigour potential in the field. Fifteen six-row barley (Hordeum vulgare L.) cultivars were used in the study, from two seed sources grown in different years, and four replicate assays of all three tests were conducted in controlled conditions at 5, 10, 15 and 20 °C. Field emergence rate (FDE = days to 75% seedling emergence) was also assessed in replicated plot trials grown at Edmonton and Ellerslie, Alberta in 1997, using the same seed sources. Three seeding dates were used at each site to obtain a range of soil temperatures at planting depth from 4 to 18 °C. Significant differences between cultivars were found for TZ, CDE and GR, but not between seed sources, and little or no interaction of cultivar with assay temperature was found. Cultivar performance was relatively similar when assessed by TZ or CDE, at all temperatures. CDE, TZ and GR results from all temperatures and both seed sources were compared by correlation to FDE results for all six planting events (two field sites × three planting dates). High and significant correlations (r > 0.51; sig., P < 0.05) were found for nearly all comparisons of each of CDE, TZ and GR with FDE. For all comparisons with FDE the average correlation for TZ was 0.68, 0.66 for CDE, and 0.69 for GR, with 10% of all possible correlations exceeding 0.80 (all sig., P < 0.05). These results indicate that all three laboratory tests at any temperature were generally effective predictors of the potential field seedling vigour of different barley cultivars. TZ and CDE appear to be useful alternatives to GR for assessing potential field seedling vigour of barley cultivars, and lend themselves to development of automated laboratory assay procedures, not possible for GR. Key words: Germination prediction tests, barley, field correlation