European virulence survey for leaf rust in wheat

With standardised near isogenic line (NIL) differentials co-operators were able to present the first comprehensive virulence survey of the European wh eat leaf rust population (1996-1999). The work included pathotype identific ation of 2608 isolates and field tests of NILs. Lr9 and Lr19 were very effe ctive all over Europe. Lr24, Lr25, and Lr28 were also effective, but in som e countries and locations substantial virulence frequencies were observed. In addition, the genes Lr12, Lr13, Lr22a, Lr34, Lr35 and Lr37 were effectiv e at the adult plant stage, but locally less so. In general, the indoor see dling tests and adult plant field tests showed good agreement. Virulence to Lr1, Lr2a, Lr24, Lr25, Lr28 and Lr29 tended to increase in the period, for the other Lr-genes the virulence frequency remained more or less stable. A mong the 105 pathotypes identified none was clearly predominant in Europe.