Geographic distribution and genotypic diversity of resistance to powdery mildew of barley in Ethiopia

Abstract

421 land race populations of barley collected from 91 Minimum Package areas in 12 provinces of Ethiopia were tested with seven powdery mildew cultures that had the corresponding virulences to 28 of the known genes for mildew resistance. 91% of the entries had resistance to one or more of the cultures. 28% of the entries were resistant to all the seven cultures. Resistance was controlled by two genes in only 22% of the entries. The genotypes of the resistant types were inferred for each province. 62 genotypes for resistance were identified for Shoa province and only 9 for Bale. Estimates of genotypic diversity for resistance were generally high for each province. The highest value is from Shoa (H' = 3.297) and the lowest from Bale (H' = 1.760). Centers of concentration for resistance are identified in northern, central and southern Ethiopia. Parallelism in the distributions of resistance to different diseases of barley and wheat is detected. Centers of concentration for resistance to one disease were also found to be centers to many other diseases. The possible strategy of protection against diseases in land race populations is discussed.