evaluation of the response of potato cultivars and various size of minitubers to the dormancy breaking methods

to shorten the dormancy period of potato minitubers and to increase a tuber's capacity to be planted sooner after being harvested, an experiment was conducted at pishtaz tissue culture company in karaj, using factorial experiment on the basis of a completely randomized design with three replications. the first factor was comprised of cultivars (agria, marfona and burren), the second minituber weight (0.3, 0.7 and 1.5gr), and the third one being the methods of dormancy breaking using carbon disulphide (cs2, 25ml/m3), gibberellic acid (ga3, 50mg/l) and control. results of the study indicated that by applying ga3 in agria and marfona cultivars, 72 and 35 percent reduction, respetively, in the length of dormancy duration was observed, while the rate of dormancy period decreased through use of cs2 in these two cultivars. dormancy breaking treatments prompted the removal of apical dominance while increased the number of sprouts in minituber. agria cultivar with an average of 2.62 sprouts per minituber bore the highest number of sprouts. by increasing the minituber weight, the length of dormancy duration decreased but the number of sprouts per minituber increased. minitubers of 0.3 gr weight sustained the highest rate of decay.