GENETICS OF LEAF-RUST RESISTANCE IN 3 SPELT WHEATS

The inheritance of leaf-rust resistance was studied in three accessions of spelt wheat (Triticum aestivum ssp. spelta L.). Accession 7831 has a gene for seedling resistance to leaf rust that is linked with Lr33 (5.4 +/- 1.05%), which is known to be on the long arm of chromosome 1B. This gene, which was either recessive or partially dominant, is designated Lr44, and because of its field reaction, should be useful in breeding rust-resistant wheats. Accession 7839 may also have this gene and an additional gene that in the seedling stage conditioned a type 2 infection to many races but little field resistance. Accessions 7831, 7839 and 7825 also have possibly in common a gene for adult-plant resistance. This gene, which did not give a high level of field resistance, was independent of Lr12, Lr13, Lr22, Lr34 and Lr35, other genes for adult-plant resistance.