Researchers Combine Resistance Genes to Improve Wheat Yields

Wild wheat species are proven sources of resistance that can be transferred to commercial varieties. Combining multiple R genes is a widely accepted gene stewardship strategy to help enhance the resistance as the simultaneous defeat of two or more effective R genes is less likely than the defeat of either gene alone.

The introgression of stem rust resistance gene Sr26 derived from tall wheatgrass into common wheat is one of the most successful examples of utilization of resistance resources from wheat wild relatives. Sr26 was transferred to wheat and the resistance has remained effective against all known P. graminis tritici (Pgt) pathotypes, including all races from the Ug99 group. A second Sr gene, Sr61, has been identified in the South African wheat accession W3757.

A compelling reason for cloning R genes is the opportunity to combine them into a single trait. The most desirable Sr genes to be combined into a transgene cassette are those with broad-spectrum effectiveness against diverse Pgt races. Virulence to most of the cloned Sr genes has been documented making isolation of Sr26 and Sr61 a valuable addition for inclusion into future transgenic cassettes.

For more details, read the article in the Borlaug Global Rust Initiative Blog.