In potato, both chlorophyll and glycoalkaloids syntheses are light induced, being responsible for the development of greening and a bitter taste in potato tubers, respectively. This work was carried out aiming at identifying a quick method to assess resistance to tuber greening in potato. Tubers of elite-clones, as well as of cultivars Achat (susceptible) and Bintje (resistant) were washed and visually assessed to greening (five-point scale) after 5, 10, 15, and 20 days of exposure to light (250 lux). A five-day exposure was enough to place cultivars Bintje (grade 1.0) and Achat (grade 3.0) in distinct classes. However, only after a 20day exposure, an accurate identification of resistance sources was possible. Principal component analysis was used to group the evaluation dates. However, it did not provide a clear-cut separation of genotypes in classes of resistance to tuber greening. Taking into account the results obtained in each evaluation date, clones CNPH036 and CNPH065 (resistant to greening), and clones CNPH039 and CNPH063 (moderately, but consistently resistant) were selected. All four clones showed value per se and for breeding. Clones CNPH009 and CNPH019 had a variable reaction in time concerning greening and, although having value per se, are not recommended for breeding purposes.
Solanum tuberosum; greening discoloration; breeding methods
