Stamova, L. and M. Yordanov

Resistance to races 2, 3, 4 and 5 of Cladosporium fulvum in S. pennellii.

As reported previously (TGC31) in progenies of crosses with S. pennellii the gene Cf-2 was identified. During 1980 we found 3 plants resistant to race 2, 3, 4 of Cladosporium fulvum (Fulvia fulva) in F₃ progenies of the cross Ideal x S. pennellii. The resistance was in the heterozygous condition.

In 1981 four lines from plants selected for resistance to the above mentioned race were inoculated with race 5 of Cladosporium fulvum. All of them segregated into resistant and susceptible plants. We found 14 resistant plants out of 20 plants in line 416/81; 5 resistant, 8 susceptible and 2 plants with necrosis in line 421/81 and 6 resistant and 7 plants with some necrotic flecks in line 424/81.

It is evident that in S. pennellii different genes are present. One of them is different from Cf-2 and Cf-4 because of resistance to race 2, 3, 4 while the other genes have the same action as genes Cf-2 or Cf-4 due to the resistance to race 5.