عامل بيماري سيامك پنهان معمولي گندم در مناطق مختلف ايران TILLETIA LAERIS شناسايي نژادهاي بيماريزاي

Identification of Pathogenic Races of Tilletia laevis, the Causal Agent of Wheat Common Bunt, in Different Parts of Iran

To identify races of T. laevis, 20 infected samples of wheat were collected from important wheat grown areas. Seeds of the differential monogenic and oligogene lines were artificially infected with teliospores of differnet samples and grown in the field. At harvesting time, percentage of infected spikes was assessed for each line, and races of each sample were determined, using standard method for race identification. According to the results, five isolates being virulent on B17 was determined as race L-1, four isolates being virulent on Bt2 and Bt7 as race L-3, two isolates being virulent on Btl and 13t7 as race L-4, eight isolates being virulent on Bt2, Bt3 and Bt7 as race L-10 and one isolate being virulent on Bt2, Bt3, Bt4, Bt6 and Bt7 as race L-17. Genes Bt2, Bt3 and Bt7 were susceptible to most of the isolates, therefore these genes are not recommended for using in breeding programs, BtS, Bt9 and Bt l3 were susceptible to some isolates. Genes Bt1 , Bt4, Bt6 (except one race), Bt5, Bt10, Bt l 1, Bt12, Bt14 and BtP were resistant to all identified races, these genes are effective for development of resistant cultivars in different parts of the Iran.