MOLECULAR MAPPING OF DURABLE RUST RESISTANCE IN WHEAT AND ITS IMPLICATION IN BREEDING

摘要

Genetic characterization of sources of durable resistance enables their strategicdeployment in breeding programs. Genomic locations of uncharacterized adult plantresistance (APR) sources to leaf rust and stripe rust diseases of wheat were determined.Two genomic regions, 3DS (Halberd) and 5DS (Cranbrook) controlled APR to bothleaf rust and stripe rust. Chromosomes 6B (Cranbrook) and 7B (Halberd) reduced leafrust severity. Chromosomes 2DS, 3BS and 7A also reduced stripe rust severities inat least one crop season. Stem rust resistance genes Sr2 (3BS) and Sr30 (SDL) fromCranbrook explained stem rust response variation. Regression analysis also indicatedstrong positive interaction of these two loci in controlling stem rust. Expression ofSr2-linked psuedo black chaff (Pbc) was controlled by a major gene on chromosome3BS and three modifiers located on chromosomes 6A, 3D and 7A. The chromosome 7Alocated region was not consistent across all seasons and sites. QTLs detected consistently in different experiments were temporarily designated as QYr/Lr3D, QYr/Lr5D,QLr6B and QLr7B.