Skin Color, Scab Sensitivity and Field Performance of Lines Derived from Spontaneous Chimeras of Red Norland Potato

Abstract

On the Canadian prairies, consumers favor red-skinned potatoes (Solanum tuberosum), with Red Norland representing the most widely grown red-skinned cultivar. However, the skin color of Red Norland is not as red as desired, particularly after extended storage. In 2004 three Red Norland tubers which appeared to have zones of darker skin color were discovered. Plants were grown from sprouts taken from both the light and dark colored zones of these tubers. The change in skin color was stable through several generations of vegetative propagation; otherwise the plants and tubers were comparable to Red Norland. This suggests that the color change was due to a chimeral mutation in the epidermis. In field trials conducted in 2005 and 2006 over 30 lines derived from the chimeral tubers were assessed for skin color, yields, tuber conformation and sensitivity to common (Streptomyces scabies) and powdery scab (Spongospora subterranea). Lines with acceptable yield and tuber configuration as well as enhanced scab resistance and/or superior red skin color were evaluated in replicated trials conducted from 2007 to 2009. Several lines were identified that had superior red skin color relative to Red Norland. Several of the new lines also appeared more resistant to common scab than Red Norland. Yield potential of the selected lines was comparable to Red Norland and when adjusted for grade out due to excessive common scab, yields of several of the chimeral lines were superior to Red Norland. This study suggests that chimeras may represent a method for rapid, low cost improvement of skin color and common scab resistance of potato, while maintaining desirable agronomic characteristics.