Genetic Diversity for Black and Brown Rust Resistance

For black rust HD 2009 showed presence of a pair of dominant complementary factors and one recessive factor. In HD 2177 indicated the operation of one dominant and one recessive factor. In HH 2189, again, a pair of dominant complementary factors and one recessive factor was observed. Crosses between resistant cultivars indicated diverse but linked factors between HD 2177 and HD 2009 and HD 2198 No segregation was found in the cross HD 2009 x HD 2189 indicating identical factors or very close linkage. For brown rust all the varieties indicated presence of two recessive genes, A suppressor was observed in Pissi Local against genes present in HD 2189. This suppressor was not operative against genes in the other two varieties. Segregation for susceptible plants in all three crosses between resistant varieties indicated diversity of genes. These were, however, not independent and linkage was observed between some of the factors. Again, the resistance to black rust was not independent of brown rust resistance.