Seed potato tubers
of the different cultivars were washed, disinfected for
5 min in a 5% sodium hypochlorite solution, thoroughly
washed with water and left to sprout. The potatoes were
then planted in closed transparent containers (500 ml,
11 cm diam., 8 cm height) filled with 200 g sterilised
(130°C, 4 h) and dried white river sand and watered with
30 ml sterile water. The closed containers were stored
in an incubator (20°C) assuring a stable temperature