Basis of long-term decreased development of Pucinia triticina in semiarid regions

The genotypes of winter wheat developed at Institute of Field and Vegetable Crops, Novi Sad, were tested for field resistance to Puccinia triticina during previous 30 years. The genotypes with infection severity less than 30 % were tested as seedlings in the greenhouse (20-25°C) using the isolate multiplied from widespread variety Pesma, with the aim of defining pseudo-resistance basis and finding differences in specific resistant ones. Lines NS 8040, BM 328 and ZJ 1675 were defined as pseudo-resistant with low reaction types increasable when second leaves were removed after inoculation, high infection efficiency and short latency period. The typical characteristic of growth was low stem, short first and long second leaf. The genotypes without such expressions were separated in four groups according to reaction types (;, ;N,:N2-3 i 4). Generally, it could also be concluded that hypersensitive reaction to parasite was based on water loss and sugar accumulation around the pustule. Infection efficiency was generally dependent on wheat type (one direction high temperature or drought stress tolerance connected genes) except in particular mentioned case of pseudo-resistance at seedlings related to higher air temperatures. The same wheat type as susceptible ones proved ZJ lines as different according to parasite specific genes. .