INHERITANCE OF LEAF RUST AND STEM RUST RESISTANCE IN ROBLIN WHEAT

The Canadian common wheat (Triticum aestivum L.) cultivar 'Roblin' is resistant to both leaf rust (Puccinia recondita Rob. ex. Desm.) and st em rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.). To study the genetics of this resistance, 'Roblin' was crossed with 'T hatcher', a leaf rust susceptible cultivar, and RL6071, a stem rust su sceptible line. A set of F6 random lines was developed from each cross . The random lines and the parents were grown in a field rust nursery artificially inoculated with a mixture of P. recondita and P graminis isolates and scored for rust reaction. The same material was tested wi th specific races of leaf rust and stem rust. These data indicated tha t 'Roblin' has Lr1, Lr10, Lr13, and Lr34 for resistance to P. recondit a and Sr5, Sr9b, Sr11, and possibly Sr7a and Sr12 for resistance to P. graminis. In a 'Thatcher' background, the presence of Lr34 contribute s to improve stem rust resistance, which appears also to occur in 'Rob lin'.