THE GENETIC ANALYSIS OF TWO INTERSPECIFIC SOURCES OF LEAF RUST RESISTANCE AND THEIR EFFECT ON THE QUALITY OF COMMON WHEAT

Abstract

Gene Lr29 transferred from Agropyron elongatum to chromosome 7D of wheat and gene LrVPM transferred from VPM1 both segregated as single genes for seedling resistance to leaf rust when backcrossed into common wheat (Triticum aestivum). Although the seedling resistance of the VPM lines was intermediate, their adult plant resistance was excellent. This resistance was not on chromosome 7D. The VPM lines also had seedling and adult plant resistance to stem rust. Resistant backcross lines with either Lr29 or LrVPM had higher kernel protein levels than did susceptible sister lines under both rust and rust-free conditions. Although this higher protein content was associated with weaker dough mixing properties, the remix loaf volume remained constant. Leaf rust infection had a detrimental effect on grain yield and kernel weight and on wheat quality as shown by decreased kernel protein content and farinograph absorption. Dough mixing strength was higher for the rust infected lines than the rust resistant lines.Key words: Triticum aestivum, wheat (spring), leaf rust resistance, protein content, breadmaking quality