Study of genetic differences in resistance of North and Nor-West bread wheat landraces to powdery mildew disease

Powdery mildew is one of important disease of wheat. In order to identify resistant genotypes to this disease in Iranian wheat landraces, a total of 31 genotypes form North and North-west provinces were investigated. The isolates of the disease were collected from Sari, Gorgan and Moghan regions and were multiplied as single clones at greenhouse. A total of ten purified isolates including four, three and 3 samples from each of Moghan, Gorgan and Sari regions were resulted and used for the assessment of the resistance in the studied germplasm. Seedlings of the genotypes were inoculated at two leaf stage by spore of each isolate, separately under Randomized Complete Block Design with three replications. The reaction to the disease was measured based on infection type. The results indicated that there were significant differences among genotypes against different isolates. The isolates Gorgan 172 and Sari 2 had the lowest and highest mean of infection type, respectively. Principal component analysis was performed to differentiate the genotypes based on their reactions to all the isolates and the results indicated that three first components justified 77.59% of the total variance. Based on these observations, the genotype 214 was identified as the most resistant genotype in the studied germplasm. Dendrogarm of cluster analysis located the genotypes in three groups with different levels of resistance to the studied isolates. The total results of this research revealed genetic resources to powdery mildew in Iranian bread wheat germplasm which could be utilized in breeding programs.

Keywords:

Germplasm. Genetic diversity , Gene pool , Gene Bank