In addition to common vegetative multiplication, potato crop can be reproduced by true potato seed (TPS). Only the limited number of pests and diseases, which are the most important causes of a decrease in potato production, can be transmitted by true potato seed. Hence, to evaluate the potential of true potato seed in comparison to potato seed tuber and mini tuber, an experiment was conducted in Marvdasht in Fars Province during summer of 2012. Treatments were arranged in a split plot experiment using a randomized complete blocks design with three replications. The main factor consisted of three planting date including 10 July, 20 July, 30 July and sub-factor was allocated to different multiplication methods in 7 levels composed of 3 seed tuber cultivar (Agria, Marfona, Santé), 3 mini tuber varieties, the same as seed tuber varieties, and BSS296 hybrid of true potato seed. The results showed that the effect of the main factor (planting date) on the yield of a tuber, weight of marketable tuber, number of the marketable tuber, and biomass was significant. The interaction effect between main and sub-factors on all characteristics was significant except for yield of the tuber, number of marketable tuber and dry matter traits. The highest yield of a plant was achieved in Santé seed tuber (36.5 t/ha) in the first planting date (10 July) and the lowest one was observed in Marfona mini tuber (19.07 t/ha). The maximum biomass was measured at the first planting date of TPS (338.1 g/plant). The marketable tubers yield in second planting date of TPS was in the lower level than Marfona seed tuber however, it was placed at the same statistical level with other seed tubers but it was better than all mini-tubers. The results of this study suggested that TPS was better than mini-tubers in mostly measured characteristics, but TPS in comparison to different seed tubers at three mentioned planting date indicated variable situations.
