Barley amylose and β-glucan:: Their relationships to protein, agronomic traits, and environmental factors

Amylose and beta-glucan are important components of barley (Hordeum vulgare L.) grain. Factors such as seed yield, test weight, seed plumpness, protein content, field location, and seasonal variation may have an effect on beta-glucan and amylose concentrations, and therefore, require additional study. Twenty-seven barley cultivars and advanced lines with varying levels of beta-glucan (4-9%) and amylose (6-27%) were grown in 2004 and 2005 in replicated plots at three locations in Idaho to evaluate agronomic traits and genotype x environment interactions. Seed yield, test weight, percentage of plump kernels, beta-glucan percentage, amylose/amylopectin ratio, and protein percentage were measured for seed samples from all plots. Estimates of variance components showed that about 49% of the variability in P-glucan concentration and about '48% in amylose starch levels can be attributed to year, location, year x location, and their interactions with genotype. Amylose was found to be negatively correlated with protein and beta-glucan content but was positively, though weakly, correlated with seed yield and test weight; beta-glucan was positively correlated with protein and percentage plump kernels but showed a weak negative correlation with seed yield.