EVALUATION OF WHEAT CULTIVARS GROWING IN KAZAKHSTAN AND RUSSIA FOR RESISTANCE TO TAN SPOT
A. Kokhmetova, O. Kremneva, G. Volkova, M. Atishova, Z. Sapakhova
Tan spot, caused by Pyrenophora tritici-repentis, is a serious foliar disease of wheat in Kazakhstan and Russia. This study was conducted to screen elite wheat germplasms to the major virulence present in P. tritici-repentis in Kazakhstan and Russia; to evaluate sensitivity of the wheat germplasm to Ptr ToxA using molecular markers; and to identify resistance sources effective against tan spot and provide wheat breeders with sources of resistance. The study of wheat germplasm reaction to Ptr isolates revealed that 64.5% of the wheat cultivars were resistant when tested to isolate 11К-14 (race 1). Over 88% of cultivars tested to 18К-14 (race 2) of P. tritici-repentis were characterized as resistant. The largest number of Russian and Kazakh cultivars, 61.9% and 65.4% respectively, was susceptible to isolate 5K-14 (race 8). In 56 wheat cultivars, containing the recessive tsn1 allele, insensitive reaction to the Ptr ToxA toxin infiltration was predicted. When wheat material was evaluated for reaction to isolate 5K-14 (race 8) and genotyped with marker Xfcp394 the insensitive reaction to the Ptr ToxA was only predicted in 20 entries. The results of molecular screening made it possible to remove the toxin sensitivity alleles from studied material. The findings suggest that most of tested cultivars growing in Kazakhstan and Russia possess racespecific resistance. This fact should be taken into consideration during development of new wheat cultivars. Due to the threat of disease epiphytotic, it is necessary to create new donors of tan spot resistance and wheat breeding material based on them.