Genetic differentiation of Slovenian sweet potato varieties (Ipomoea batatas) and effect of different growing media on their agronomic and nutritional traits

The objectives of the present study were firstly to analyse the genetic relatedness among three Slovenian sweet potato varieties; and secondly to assess the effects of different growing media on selected agronomic and nutritional traits of these varieties. Tubers of three varieties (LuÄka, Janja, Martina) with different skin/flesh colour were produced in planters under glasshouse conditions in five different growing media (perlite, peat, expanded clay, vermiculite, garden soil) from prior raised seedlings. Genetic analysis was performed using a set of eight single sequence repeats markers. According to Nei’s genetic distance and pairwise population Fst analysis, the most related varieties are Janja and Martina; in contrast, LuÄka and Martina show the weakest genetic relationships. The following agronomic traits were evaluated: vine length, thickness of vine-base, number of branches, weight of above ground part, number of leaves plant–1, number of tubers plant–1 and tubers weight plant^–1. Between nutritional traits total phenolic content (TPC), antioxidant potential (AOP) and ascorbic acid content (AA) were determined in the range: 36.2 to 65.1 mg gallic acid equivalent 100 g^–1 fresh weight, 0.18 to 0.56 mg Trolox equivalents g^–1 FW and 13.7 to 23.5 mg 100 g^–1 FW, respectively. Significant interactions of growing media (factor A) × variety (factor B) were observed for thickness of vine-base, weight of above ground part, AOP, TPC and AA. Overall, results showed variation in varieties response to growing media. Growing media provide a discriminant classification of the sweet potato varieties according to their agronomic and nutritional traits.