Isogenic Barley Lines for Reaction to Erysiphe graminis F. Sp. Hordei1

The procedure is described for developing 10 pairs of barley (Hordeum vulgate L.) lines, each isogenic except for a specific pair of alleles conditioning resistance and suspecptibility to culture CR3 of Erysiphe graminis (DC.) Merat hordei Em. Marchal. Each pair of lines was selected after four backcrosses to the cultivar ‘Manchuria,’ followed by 12 to 15 selfed generations. Four pairs of lines, developed from cultivars ‘Goldfoil,’ ‘Hanna,’ ‘Kwan,’ and ‘Psaknon’ differ by the resistance genes Ml‐g, Ml.h, Ml‐k, and MI‐p and their recessive alleles, respectively. Six pairs of lines differ by genes at the complex Ml‐a locus. The fines developed from cultivars ‘Algerian,’ ‘Franger,’ and ‘Durani’ differ by the resistance genes Ml‐a, Ml‐a6, and Ml‐a10 and their recessive alleles, respectively; and those developed from cultivars ‘Multan,’ ‘Long Glumes,’ and ‘Rupee’ each differ by one resistance gene and its recessive allele.