Selection for greater beta-glucan content in oat grain

Oat (Avena sativa L.) beta -glucan lowers serum cholesterol in humans. Deve lopment of oat cultivars with greater groat (caryopsis) beta -glucan conten t would increase the nutritional and economic value of the crop. The object ives of this experiment were to evaluate the response to phenotypic selecti on among individual So plants for greater groat beta -glucan content in two genetically broad-based populations; to compare selected experimental line s to standard check cultivars; and to estimate genetic variances and herita bilities and to test for nonadditive genetic variance for beta -glucan cont ent. We measured groat beta -glucan contents of check cultivars and parenta l lines and random S-0:1 lines from initial and selected generations of eac h population grown in field experiments in 1996 and 1997 at two Iowa locati ons. Mean beta -glucan content increased from 53.9 to 59.9 g kg(-1) in one population, and from 63.5 to 66.0 g kg(-1) in the other, following selectio n. Genetic variance of beta -glucan content decreased by 9 to 22% following selection, but heritability for beta -glucan content did not change signif icantly. Heritability estimates ranged from 0.80 to 0.85 on a line mean bas is. Additive variance was the only substantial component of genetic varianc e. Some experimental lines had significantly greater beta -glucan content t han the best check cultivars and lines. Phenotypic selection for greater gr oat beta -glucan content will be effective for developing cultivars with el evated beta -glucan contents.