Improvement of diagnostic markers for resistance to and application for selection of resistant germplasms in potato breeding.

Occurrence of pale potato cyst nematode, (Stone) Behrens, was first recorded in Japan in 2015. Among several control measures, cultivation of resistant potato ( L.) varieties is the most effective in cost and environmental impact. As no -resistant varieties have yet been developed in Japan, great emphasis is being placed on screening of germplasm possessing the resistance and development of the resistant varieties. In this study, we first improved previously reported DNA markers linked to the resistance loci ( and ) and then used these to screen more than 1,000 germplasms to select several candidate germplasms with resistance. We performed inoculation testing on the selected candidates and identified several resistant germplasms to the Japanese population. Furthermore, we developed a simultaneous detection method combining three DNA markers linked to and (Wollenweber) Behrens resistance loci. We validated the ability of C237-I marker to select resistant allele of and predict the presence of resistance in a Japanese breeding population. Resistant germplasms identified in this study could potentially be used to develop -resistant varieties. The marker evaluation methods developed in this study will contribute to the efficient development of resistant varieties.