The position, presence or absence of leaves and bud numbers of the explant were evaluated on the in vitro multiplication of potatoes. The culture medium was constituted by salts and vitamins of MS, added with 100 mg L-1 myo-inositol, 30 g L-1 sucrose and 6 g L-1 agar. Different types of nodal segments were used (basal and apical, with and without leaves, having, one, two and three axillary buds). The material was maintained in growth room at 25±2ºC, 16 hours photoperiod and 19 µE m-2 s-1 irradiance during 32 days. For height and number of regenerate sprouts, the best results were obtained with explants originating from the basal position and with three axillary buds. The multiplication rate was higher in explants with a single bud independently of the position. Only in basal explants the presence of leaves improved the multiplication rate. We concluded that, when heterogeneous explants are used the initial characteristics of the explants can promote variation in the final answer and cause mistakes in the development of the in vitro material.
Solanum tuberosum L.; micropropagation; growth; explant type
