Potato virus Y (PVY) impacts potato production worldwide by reducing potato yield, tuber quality, and successful certification of seed. Extreme resistance to PVY is conferred by three genes (Ry_adg, Ry_sto, and Ry_chc) which have been introgressed from wild species into cultivated varieties. Both Ry_sto and Ry_adg are used in many breeding programs worldwide, but Ry_chc is found in only a limited number of varieties and previously had been absent in varieties and germplasm representative of the russet market class that is widely grown in North America. Five russet breeding clones were identified as having the molecular marker associated with Ry_chc. Confirmation of the presence of Ry_chc was established following field and greenhouse screening of the clones for resistance to PVY with no infection by the virus being observed. These clones also have been characterized as having resistance to late blight and cold-induced sweetening of tubers and all are male-fertile as well. The unique assemblage of resistances in this russet germplasm will be of value to the potato breeding community in the development of russet potato varieties, especially with respect to Ry_chc which previously has not been reported as being present in this potato market class.

马铃薯 Y 病毒(PVY) 通过降低马铃薯产量、块茎质量和种子成功认证来影响全球马铃薯生产。三个基因（Ry _adg、Ry _sto和Ry _chc）赋予了对 PVY 的极端抗性，这些基因已从野生物种渗入到栽培品种中。无论RY _STO和RY _ADG在许多育种计划全球范围内使用，但RY _CHC仅在数量有限的品种中发现，以前在代表北美广泛种植的赤褐色市场类别的品种和种质中不存在。五个赤褐色育种克隆被鉴定为具有与Ry _chc相关的分子标记。确认Ry _chc的存在在对PVY抗性的克隆进行田间和温室筛选后建立了克隆，未观察到病毒感染。这些克隆的特征还在于对晚疫病和冷诱导的块茎增甜具有抗性，并且都是雄性可育的。这种赤褐色种质中独特的抗性组合对于开发赤褐色马铃薯品种的马铃薯育种社区具有重要价值，特别是对于以前没有报道过存在于该马铃薯市场类别中的Ry _chc。