Somatic Mining for Phytonutrient Improvement of ‘Russet Burbank’ Potato

Screening of >800 somaclones of ‘Russet Burbank’, North America’s leading French fry cultivar, for improved yield and processing quality, led to the selection of 25 advanced lines. Three replicates of 3–5 tubers each from advanced lines were assessed after 5 months storage for antioxidant and polyphenol attributes; a subject receiving increased attention among plant breeders, nutritionists, and consumers. Phytonutrients affecting antioxidant components and total antioxidant capacity per serving (150 g fresh matter; one serving size) varied significantly among tubers of the 25 somaclones as well as between these somaclones and ‘Russet Burbank’ control plants (field tuber-derived and plantlet-derived). Several phenolics, including chlorogenic acid, caffeic acid derivatives, ferulic acid derivatives as well as the flavonoid rutin, ranged in concentration from 10- to 100-fold with some lines exceeding control tuber concentrations by >7-fold. Similarly, ascorbic acid ranged >3-fold (47.21 to 208.63 mg) on a per serving basis with some lines showing significantly greater concentrations than the control plantlet derived tubers (93.82 mg) by >2-fold. Antioxidant capacity, estimated using 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), ranged up to 5-fold for the advanced somaclones (2,121.34 to 11,163.07 μM trolox equivalent/serving). Less variation occurred with other antioxidant capacity tests (DPPH, Folin-Ciocalteu). Overall 17/25 lines had increased antioxidant components. HPLC assays were necessary to confirm lines with better phytonutrient profiles. Somaclonal selection offers clear benefits for phytonutrient improvement in potato and can follow selection for yield and processing attributes.