Field trials were carried out in 1992 and 1994 at the Experimental Field in Chylice (Warsaw Agricultural University) using differentiated seed material; regular certified seeds of diameter 3-4 cm and minitubers of diameter 1-2 cm. Minitubers were obtained from the plants multiplication by in vitro technique. The influence of seed material and time of furrows formation (autumn or spring) on the total and net yield of tubers were evaluated. The analysis of the experiment results lead to the conclusion that sowing of minitubers is acceptable but hight number of mechanical damages caused by the seeder Pneumassem II have to be eliminated. Mean yield of tubers for all experimental treatments was similar. The mean did not differ significantly at the level 0,05.