Characterization of traditional small potato (Solanum tuberosum L.) cultivars for nutritional, quality traits and ploidy level

Traditional small potato cultivars of North Eastern region of India are an important food source, but no documentation is available regarding their ploidy level and nutritional worth. The study was undertaken to explore these cultivars to determine their ploidy level by flow cytometry method. Fluorescence-activated cell sorter (FACS) based method was used for the analysis of ploidy level and the known diploid potato clone Solanum chacoense was used as the reference clone. The ploidy level of these cultivars was determined by comparing the value of mean peak position of G1 of reference diploid clone with mean peak position of G1 of small potato cultivars. Results indicated that all the 11 small potato cultivars collected from the Northeastern region were tetraploid with an average genome size of 837.38 Mb although they were suspected to be diploid based on the tuber characters and overall plant morphology. These cultivars were characterized by having anthocyanin pigmentation of newly emerged sprouts and eye on tuber, small and narrow leaf, long stolon length (average 7.38 cm) and high number (average 33.90/plant) of very small (average 7.41 g) tubers compared to the commercial potato varieties. However, these cultivars surpassed India's commercial tetraploid potato varieties for dry matter, starch, ascorbic acid, beta-carotene and total phenol contents. Appreciably rich nutritional profile coupled with matching levels of ploidy not only enhanced the biodiversity of cultivated potato but also suggested the possibility of utilizing these cultivars in the breeding programme to enhance nutrient and antioxidant contents.