Gene pyramiding for developing high-yielding disease-resistant wheat varieties
362In this chapter gene pyramiding for developing high yielding disease resistant wheat varieties, wheat rusts in India, the details of occurrence, epidemiology, and management of rusts particularly the pathotypes of leaf rust pathogen in field and spectrum of dominant pathotypes of wheat rusts in India over the years are given in detail. Further the importance of rust monitoring for the sake of gene deployment by understanding types of rust resistance in wheat to take up the gene deployment strategies to combat rusts are discussed in depth. The usefulness of linked genes used in the gene pyramiding program and the effective introgression of genes through hybridization and marker-assisted selection to develop durable rust resistant varieties particularly the effective genes against stem rust race Ug99 at IARI, Wellington are discussed. The details on origin, chromosomal location, infection type, source stocks, environmental variability, and stocks developed at IARI, RS, Wellington for effective single leaf rust genes viz., Lr9, Lr19, Lr24, Lr26, Lr28, Lr32, Lr34, Lr35, Lr37, Lr39, Lr44, Lr45, Lr46, Lr47, Lr53, Lr57, Lr67, and Lr68, stem rust genes, Sr2, Sr24, Sr25, Sr26, Sr2, Sr30, Sr31, Sr32, Sr33, Sr36/Pm6, and Sr38 and stripe rusts Yr9, Yr10, Yr15, and Yr17 are given. For achieving durable resistance in wheat, pyramiding new rust resistance genes is the effective way.