The effects of nitrogen rates on minituber seed potato (Solanum tuberosum L.) was evaluated on cv. Monalisa, propagated in vitro. The experiment was conducted in a greenhouse. Two tissue culture propagated potato plantlets were planted in 3 L pots with substrate. Five N rates, 0; 50; 100; 200 and 400 mg kg-1 of N, as NH4NO3, were evaluated in randomized complete block design and five replications. The SPAD index in the fourth leaf (LQ) increased with the increase of N rates and decreased with the plant age. N-NO-3 content in the LQ dry matter, associated with the maximum minitubers yield was 0.015 dag kg-1. The maximum minituber dry matter, the maximum plant dry matter and maximum minituber yield were 25.74; 31.93 and 138.8 g pot-1, respectively, with 0 mg kg-1of N.
Solanum tuberosum; fertilization; unheated greenhouse
