Correlated Responses to Selection for Greater B-Glucan Content in Two Oat Populations

Abstract

<p>Oat (<em>Avena sativa</em> L.) β-glucan lowers serum cholesterol in humans. Thus, enhancing its content in oat cultivars for human consumption is desirable. Phenotypic selection for greater β-glucan content was effective in two broad-based oat populations, BG1 and BG2. The initial and selected cycles of each of these populations were evaluated in 1996 and 1997 at two Iowa locations to determine the correlated responses of agronomic and grain quality traits to selection for greater β-glucan content. Correlated responses were generally unfavorable for agronomic performance, but favorable in terms of human nutritional value of oat grain. Mean protein content increased by 5% in one population while mean oil content and heading date did not change. Mean grain yield, biomass, and test weight were reduced by 25, 23, and 2%, respectively, in one population and not affected in the other. Plant height decreased by 5% in one population only. Genotypic variances were unchanged by selection, except the genetic variance for plant height in BG2 increased. Selection strengthened negative genotypic correlations between β-glucan content and grain yield, biomass, and oil content in both populations, and between β-glucan content and test weight, heading date, and height in one population. β-Glucan yield (the product of β-glucan content and grain yield) was positively genotypically correlated with both grain yield (<em>r</em> = 0.92 in both populations) and β-glucan content (<em>r</em> = 0.66 and <em>r</em> = 0.26 in the two populations). Selection for greater β-glucan yield could be used to improve β-glucan content and grain yield simultaneously.</p>