M. TODOROVA1 and V. KIRYAKOVA2
1 University of Forestry, BG-1756 Sofia, Bulgaria
2 Dobroudja Agricultural Institute , BG-9520 General Toshevo, Bulgaria
TODOROVA, M. and V. KIRYAKOVA, 2001. Virulence survey of Puccinia recondita f. sp. tritici in Bulgaria during the period 1996-1999. Bulg. J. Agric. Sci., 7: 275-278
Seventeen NILs of Thatcher were used to determine the virulence frequencies within the Puccinia recondita f. sp. tritici population in Bulgaria during the period 1996-1999. No virulence was detected to Lr9 and Lr19. The effectiveness of Lr1, Lr2a and Lr2b was relatively high and stable. In opposite to them virulence to Lr2c was very high and increased slowly from 1996 to 1999. Variation in effectiveness of Lr15 and Lr17 was higher. Most isolates were virulent to Lr10, Lr11 and Lr21 and no significant changes were established. Lr23 was low effective but the number of virulent isolates on it in 1997 was surprising low. The variation in virulence to Lr24 was relatively low as it was moderately resistant. Lr26 and Lr28 had low protection. Lr16 and Lr30 were totally ineffective.