The effect of mini-tuber size and chemical treatments on breaking seed dormancy of potato (Solanum tuberosum L.)

Seed dormancy is one of the important problems among potato minitubers. It decreases the germination percentage by rotting the tubers. To overcome this problem an experiment was conducted at Agricultural Research Institute of Hamedan in 2012-2013. The experiments were carried out in factorial randomized complete design with two different treatments, the weight of minituber in three levels (1-3 g, 3-5 g and 5-10 g) and chemical treatments in seven levels (no treatment, 150 ppm gibberellic acid in 1 h, 300 ppm gibberellic acid in 1 h, 1% thiourea in 1 h, 0.5% thiourea in 1 h, 45 ml.m-3 carbon disulfide in 24 h, 45 ml.m-3 carbon disulfide in 48 h) with three replications per treatment. The Sante variety was tested for minituber size. After seed dormancy breakage, the days to germination, number of sprouts per minitubers and the sprout diameter were studied and then the mini-tubers were grown in pots. After tuber collection (harvesting), the number of tuber per plant, tuber weight and the total weight of all tubers were measured. We observed the highest stem diameter in 5 – 10 g tubers and the lowest sprout length in 1-3 g tubers. Also, among different breaking seed dormancy treatments, the 45 ml carbon disulfide in 48 h showed the significant increase in sprout length compare to the 45 ml carbon disulfide in 24 h which resulted the highest tuber size and weight. The gibberellic acid (300 ppm) treatment showed the highest number of tubers. The interaction study among treatments showed that, the 45 ml carbon disulfide in 48 h produced tubers with different size and they were high in weight compare to the others.