Effect of inorganic nitrogen nutrition on cytokinin-induced potato microtuber production in vitro

The effect of inorganic nitrogen nutrition on the induction and development of microtubers by cytokinin-induced tuberization was studied in four potat o genotypes belonging to different maturity groups. The objective of this s tudy was to investigate whether a reduction in total nitrogen level in the Murashige & Skoog medium would improve cytokinin-induced tuberization rate. The effect of three levels of total nitrogen (15, 30 and 45 meg) on tuberi zation was studied at constant (20 meg K) and varying potassium levels appr oximating to 5, 10 and 15 meg. Reducing the total nitrogen supply increased the number but decreased the size of microtubers. The total availability o f potassium in the medium influenced the effect of reduced nitrogen level o n the rate of assimilate partitioning (harvest index) during cytokinin-indu ced microtuberization.