Chromosome 6U from Aegilops geniculata Roth Carrying Powdery Mildew Resistance in Bread Wheat

Abstract

The production and isolation of a wheat—Aegilops geniculata disomic addition line and of monosomic substitution line resistant to powdery mildew at the seedling and adult plant stages are described. Cytological analysis revealed the presence of an acrocentric chromosome in the resistant derivatives. Polyacrylamide gel electrophoretic analysis indicated differences in the β-zone of the reduced by mercaptoethanol treatment seed protein pattern between the wheat parent cv. Trakya and the resistant derivatives. A component with a high staining intensity in the β-zone was assumed to be a marker for the chromosome 6 of Ae. geniculata. The isoenzyme activity at the Got-1 and Est-4 loci of the lines was lower than that of wheat. By analyzing the isoenzymes of the Amp-1 locus of the addition plants, a quantitative marker of Ae. geniculata 6U chromosome was identified. The progeny of the plants with the 2n = 43 and 2n = 42 chromosomes carrying the chromosome 6U added or mono-substituted for the wheat 6D chromosome segregated for powdery mildew resistance. The mono-and/or double conditions for this chromosome could be maintained by selecting resistant plants in the segregated populations.