[Determination of the composition and the allelic state of disease and pest resistance genes in potato parental lines using DNA markers].

The allelic dosage of disease and pest resistance genes was determined in 11 prospective potato varieties and hybrids by means of detecting the corresponding PCR DNA markers in their progeny from crosses with specially selected testers. It was revealed that most (65%) resistance genes in the analyzed parental lines were present as a single dominant allele (simplex). Nevertheless, we were able to find some multiplex lines valuable for breeding. The Yanka variety and the clone 52-03-16 had one triplex and one duplex of resistance genes, the Lilea and Charaunik varieties and the clone 106-04-17 had two resistance genes in duplex, and the Uladar and Falvarak varieties and the clone 45-04-24 were duplex for some single genes. The highest number of multiplex lines was detected for the genes Ry sto , H1, and Sen1. Only simplex genotypes were revealed for the Gro-1-4 and PLRV1 genes.

Assessment of the possibility of direct crossing between cultivated potato and two wild allotetraploid relatives.

The cultivated potato Solanum tuberosum L. is an autotetraploid with Endosperm Balance Number (EBN) of 4. There are some allotetraploid 2EBN wild species with desirable traits for potato improvement. However, it is very difficult to cross between these two groups due to differences in EBN. Eleven genotypes of autotetraploid cultivated potato including the six cultivars of subsp. Tuberosum (tbr) and five clones of subsp. Andigena (adg) were crossed with two wild allotetraploid species: S. acaule (acl) and S. stoloniferum (sto). For asses the pollen-pistil incompatibility, some ofpollinated flowers were fixed in Carnoy's solution and stained with aniline blue. Evaluation with fluorescent microscope revealed that pre-zygotic pollen-pistil incompatibility in these crosses is frequent. The pistils of both subsp. of cultivated potato were incompatible with pollens of acl but when sto used as staminate parent it was compatible with five cultivars of subsp. Tuberosum, but incompatible with most ofsubsp. Andigena (4 clones). From 739, 4x, 4EBN x 4x, 2EBN crosses we couldn't get any viable seed. In reciprocal crosses, allotetraploid species were pollinated with a mix of pollens from Tuberosum or Andigena clones. The crosses of sto x adg, acl x adg and acl x tbr were compatible but in the case of sto x tbr the situation was not clear. From these crosses 157 fruits were obtained but most of them contained only shrink seed and we find just one hybrid from the sto x tbr combination. The hybrid was tetraploid (2n = 4x = 48) and vigorous with profuse flowering and good fertility. When this hybrid was used as the pistillate parent it was compatible with both parental species.