Genetic base of durable resistance to Puccinia triticina of two Serbian varieties

The durable resistant varieties were developed more than 15 years ago. The basis of the resistance was investigated at seedling stage according to reaction type (RT) at air temperatures 20-25°C. The F2 generations of varieties Anastasia or Selekta x Lr 1, Lr 2a, Lr 3, Lr 13, Lr 14a, Lr 16 or Lr 26 were tested with isolates producing low RT on first two mentioned Lr lines. The presence of these single resistant genes in the varieties was excluded by presence of susceptible plants in F2 progenies of adequate crosses. The resistant combinations were Lr 3+B as Lr3+C in Selekta and Lr26+E, Lr26+C as EC in Anastasia. According to lower infection efficiency and yellowing of the above tip top part the C was similar or Lr 34. The Lr 13 and 14a were near the same effective at seedlings when were added to proposed combinations in parents. According to F1 results in field the most effective over season combination was achieved by crossing the investigated varieties because of two LP prolong able complementary genes and accumulation of three infection severity responsible ones