Global stem rust phenotyping network for wheat improvement

Sridhar Bhavani


CIMMYT

Ruth Wanyera, Godwin Macharia, Ravi Singh, Ayele Babebo, Girma Bedada



An effective partnership between CIMMYT, KALRO, EIAR and Delivering Genetic Gains in Wheat (DGGW) project on global stem rust phenotyping has made a significant progress and impact on the Global wheat community in addressing the threat of Ug99 race group and other important stem rust races in the region. International stem rust phenotyping networks play a key role in evaluating global wheat germplasm from many countries and institutions: identifying new sources of resistance, pre-breeding, CIMMYT-Kenya shuttle breeding, pathogen survey and surveillance, varietal release and genomic selection. About 600,000 lines have been screened against Pgt race Ug99 and derivatives since 2005, and the screening capacity at KALRO has increased to 50,000 lines each year from over 20-25 countries and research institutions each year. The results from international nurseries show a shift to higher frequencies of lines with resistance to race Ug99 since the screening activities were initiated in 2008.
KALRO and EIAR and several national programs have a dynamic and successful breeding programs that benefit from collaboration, testing, and release of materials coming out of the CIMMYT breeding program. The release of over 15 varieties in Kenya as well as in Ethiopia and more than 90 varieties released in several countries globally over the years is a testament to the success of the program. with spillover effects of varieties released in Burundi, Rwanda, and Uganda.
CIMMYT-Kenya shuttle breeding has resulted in rapid recycling of over 2000 breeding populations each year between Mexico and Kenya to evaluate and select lines in early generations against virulent stem rust races in Kenya to ensure lines have adequate levels of resistance are advanced not only in early generations of breeding cycle but also materials in the yield trails (10,000 annually) that are later constituted as international nurseries and distributed to National programs and partners.