SYNTHETIC HEXAPLOIDS X TRITICUM-AESTIVUM ADVANCED DERIVATIVES RESISTANT TO KARNAL BUNT (TILLETIA-INDICA MITRA)

Eighty-one advanced bread wheat lines derived from 12 crosses involvin g seven synthetic hexaploids (Triticum turgidum x T. tauschii) and sev en high yielding T. aestivum cultivars were evaluated for Karnal bunt (Tilletia indica Mitra) resistance during two crop seasons at CIANO, C iudad Obregon, Sonora, Mexico. Ten random tillers of each test entry a t boot stage were injected with a suspension of sporidia in water (10, 000 sporidia/ml of water). At maturity the inoculated spikes were thre shed individually and evaluated for percent Karnal bunt infected grain s. Based on the mean Karnal bunt score of each entry for two seasons, 17 lines showed less than 3% infection as compared to 82.1% of the sus ceptible T. aestivum check cultivar WL711. Most of the resistant culti vars were derivatives of Chen/T. tauschii (205)//Kauz cross. One entry from the cross Chen/T. tauschii (205)//Weaver remained immune (0% inf ection) after two years of test. Finally, these derivatives provide ad ditional source of genetic variability for Karnal bunt resistance in b read wheat improvement.