ASSESSMENT OF MODIFYING EFFECT OF KINETIN ON INVITRO TUBERIZATION OF INDUCED AND NON-INDUCED TISSUES OF SOLANUM-TUBEROSUM

''Katahdin'' potato plants (S. tuberosum L.) were grown under inducing (26.degree. C day 12.degree. C night with an 8 h photoperiod) and non-inducing (28.degree. C day/25.degree. C night with a 16 h photoperiod) conditions. Apical, medial and basal nodal stem segments from each plant harvested were surface sterilized and aseptically transferred to culture flasks containing Murashige and Skoog''s medium with and without kinetin. After culturing in dark for 4 wk at 24.degree. C, percentage tuberization of segments from induced plants was significantly greater than for non-induced segments. Addition of kinetin to the culture medium eliminated this effect of induction. Apical segments from induced plants tuberized more frequently than those from non-induced plants and those from lower on the stem. Addition of kinetin eliminated this stem position effect. Percentage elongation was significantly greater in segments from non-induced than induced plants. Addition of kinetin reduced percentage elongation in non-induced segments to that for induced segments. Percentage elongation was greatest in apical segments from non-induced plants and this position effect could be eliminated by addition of kinetin.