Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2021
Publication Date: 10/30/2021
Citation: Elison, G.L., Novy, R.G., Whitworth, J.L. 2021. Russet potato breeding clones with extreme resistance to potato virus Y conferred by rychc as well as resistance to late blight and cold-induced sweetening. American Journal of Potato Research. 98:411-419. https://doi.org/10.1007/s12230-021-09852-1.
Interpretive Summary: Potato virus Y (PVY) is a devastating disease which reduces potato yield and tuber quality. Genetic resistance to PVY is conferred by three genes which can be bred into domestic potato varieties and completely prevent infection by the virus. Two of these (Ryadg and Rysto) are commonly used in breeding programs worldwide, but the third (Rychc) is found in only a small number of varieties and is absent in the russet potatoes predominantly grown in North America. During routine testing of breeding material, five russet breeding clones were unexpectedly found to possess Rychc. Confirmation of the resistance was established with rigorous field and greenhouse tests. In addition, the clones were found to have two other highly desirable traits: resistance to late blight and resistance to cold-induced sweetening. Identification of Rychc in our russet material greatly decreases the time and effort needed to incorporate it into our breeding program. Having a larger variety of resistance genes available to the breeding program greatly increases our ability to develop potato varieties with resistance to PVY.
Technical Abstract: 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 (Ryadg, Rysto, and Rychc) which have been introgressed from wild species into cultivated varieties. Both Rysto and Ryadg are used in many breeding programs worldwide, but Rychc 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 Rychc. Confirmation of the presence of Rychc was established following rigorous 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 Rychc which previously has not been reported as being present in this potato market class.