Natural outcrossing in wheat substitution lines

Abstract

The frequency of natural outcrossing in two chromosome substitution lines of wheat (Triticum aestivum L. em. Thell) was estimated with one procedure and in a third substitution line with another method. The first procedure utilized a dominant inhibitor of awns as the marker to detect outcrosses in the progeny of an awned line. This trial was repeated at five locations. Segregation tests indicated that up to 80 (0.32%) awnless outcrosses were present in an estimated sample of 25,450 progeny. The second method measured outcrossing between a substitution line and two unrelated varieties by observing the intermediate phenotype of the F₁ spike. Confirmation of hybridity was obtained for each plant by using starch gel electrophoresis on the endosperm of five F₂ seeds from the intermediate F₁ spike. This method indicated 0.16% natural outcrossing.