Cytogenetical Stndies in Wheat. VII Gene Lr23 for Reaction to Puccinia recondita in Gabo and Related Cultivars

Gene Lr23, previously designated LrG, was located on the short arm of chromosome 2B and showed approximately 4 % recombination with the centromere and 22 % recombination with Sr9 which is situated on the long arm. In some crosses Lr23 was recessive whereas in others it was partially dominant. The degree of dominance of Lr23 was greater at higher temperatures. A gene which inhibited the expression of Lr23 under Canadian test conditions acted as a partial inhibitor, or modifier, under Australian test conditions.