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n important step towards reducing the vulnerability of wheat in Africa and Asia to the Ug99 race of the stem rust pathogen is the substitution of current susceptible varieties with superior resistant varieties. In the 2008-2009 cropping season both seed multiplication and dissemination of Ug99 resistant varieties were initiated in Afghanistan, Bangladesh, Egypt, Ethiopia, Iran, India, Nepal and Pakistan. Ug99 resistant varieties must occupy about 5% of the area sown to wheat in each country to ensure sufficient seed to displace current popular varieties. Because of the underdeveloped seed industry and small farm sizes in most of these countries, various strategies are being applied for rapid multiplication and dissemination of resistant varieties. Approaches being used include pre-release seed multiplication while candidate resistant lines are being tested in national evaluation trials and farmer participatory selection. Resistant varieties are already released in Afghanistan, Bangladesh, Egypt and Pakistan and more varieties are expected to be released in 2010 in these and other countries. Our results show that some new Ug99 resistant lines have yield superiority over dominant local varieties. Activities and progress in seed multiplication using existing and new Ug99 resistant varieties are discussed. [ABSTRACT FROM AUTHOR]

Background: Wheat is the most important staple crop in Afghanistan and accounts for the main part of cereal production. However, wheat production has been unstable during the last decades and the country depends on seed imports. Wheat research in Afghanistan has emphasized releases of new, high-yielding and disease resistant varieties but rates of adoption of improved varieties are uncertain. We applied DNA fingerprinting to assess wheat varieties grown in farmers' fields in four Afghan provinces. Results: Of 560 samples collected from farmers' fields during the 2015–16 cropping season, 74% were identified as varieties released after 2000, which was more than the number reported by farmers and indicates the general prevalence of use of improved varieties, albeit unknowingly. At the same time, we found that local varieties and landraces have been replaced and were grown by 4% fewer farmers than previously reported. In 309 cases (58.5%), farmers correctly identified the variety they were growing, while in 219 cases (41.5%) farmers did not. We also established a reference library of released varieties, elite breeding lines, and Afghan landraces, which confirms the greater genetic diversity of the landraces and their potential importance as a genetic resource. Conclusions: Our study is the first in wheat to apply DNA fingerprinting at scale for an accurate assessment of wheat varietal adoption and our findings point up the importance of DNA fingerprinting for accuracy in varietal adoption studies. [ABSTRACT FROM AUTHOR]