Markers of genes for resistance to late blight, potato virus <i>Y</i> and potato cyst nematode identified in advanced interspecific potato hybrids

Abstract

Background. The harmful organisms affecting potato cause great economic damage in all areas where the crop is grown. One of the most economically important pathogens is the potato late blight (agent Phytophthora infestans Mont. (de Bary)). Also, Potato Virus Y (PVY) and potato cyst nematode (PCN) of the Ro1 pathotype, the only one that occurs in the Russian Federation, cause significant yield losses. Materials and methods. Phytopathological and molecular screening was carried out on original interspecific potato hybrids obtained in 11 crossing combinations, seven of which were studied for the first time. Hybrids resulted from crosses that involved Mexican and South American potato species as sources of late blight and PVY resistance. Field observations of late blight resistance were conducted during three seasons under high infection pressure. A part of plant material was screened in laboratory tests. PCR tests employed 9 DNA markers of genes associated with resistance to Ph. infestans, PVY and PCN of Ro1 pathotype used in our previous study. Results. In field evaluation, hybrid clones mostly expressed high, and a part of them moderate late blight resistance. Of the 6 markers of the used Rpi genes, at least two were detected in most clones, while some had 3 or 4 markers. Some clones were found to have markers of PCN resistance genes and of several genes for resistance to PVY. The cytoplasm type was determined for all plant material. Conclutions. Within a small but pedigree-diverse set of interspeсific hybrids, the markers of resistance genes to all three pests were found. A part of clones obtained by using the sources of PVY and late blight resistance which we had identified, were found to contain two or more resistance genes to these pathogens. According to the results of molecular tests, the clones were found to carry several markers of late blight and PVY resistance genes. Original interspecific potato hybrids with determined late blight resistance levels, cytoplasm type and availability of markers of genes for resistance to three pests can be used in further hybridization.