Sixty-six wheat cultivars grown in Belarus, Poland, Russia and the Ukraine were tested for mildew response to a collection of 11 different isolates of Erysiphe graminis DC f. sp. tritici Marchal. Nineteen cultivars have shown a susceptible reaction and eighteen were characterized by susceptible or intermediate responses. Fourteen cultivars revealed isolate-specific response patterns that could be attributed to major known resistance genes or gene combinations. Twelve cultivars have one documented gene: Pm5 in eight cultivars, Pm2 in two cultivars and Pm8 also in two cultivars. One cultivar has two genes (Pm2 + Pm6), while another cultivar carries a combination of three genes (Pm1 + Pm2 + Pm6). Fifteen cultivars were characterized by response patterns not documented so far or by a known resistance response combined with an undocumented resistance. Apparently three cultivars with the T1BL.1RS wheat-rye translocation have a gene suppressing the Pm8 mildew resistance. One cultivar was resistant to all the used isolates. Its resistance might be conditioned by an unknown major gene or combination of genes.
The winter wheat cultivar Red Chief has been identified as the wheat cultivar most resistant to Pyrenophora tritici-repentis (Ptr). This study was undertaken to determine the inheritance, chromosomal location and molecular mapping of a tan spot resistance gene in Red Chief. chi2 analysis of the F2 segregation data of the hybrids between 21 monosomic lines of the susceptible wheat cultivar Chinese Spring and the resistant cultivar Red Chief revealed that tan spot resistance in cv. Red Chief is controlled by a single recessive gene located on chromosome 3A. Linkage analysis using SSR markers in the Red Chief/Chinese Spring F2 population showed that the tsr4 gene is clustered in the region around Xgwm2a, on the short arm of chromosome 3A. This marker has also been identified as the closest marker to the tsr3 locus on chromosome 3D in synthetic wheat lines. Validation analysis of this marker for the tsr3 and tsr4 genes using 28 resistant and 6 susceptible genotypes indicated that the 120 bp allele (the tsr3 gene) specific fragment was observed in 11 resistant genotypes, including the three synthetic lines XX41, XX45 and XX110, while the 130 bp allele was amplified only in cv. Red Chief and Dashen. Xgwm2a can be used to trace the presence of the target gene in successive backcross generations and pyramiding of the tsr3 & tsr4 genes into a commonly grown and adaptable cultivar.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.