Effect of chemical treatments used for dormancy breaking on the number of stems and tubers of Hungarian potato varieties

The length of tuber dormancy of potato varieties is an important factor in the profitability of the potato sector. Under temperate climatic conditions longer dormancy is more advantageous. However, in case of multiple planting within one growing season, in seed multiplication programs or during rapid post-harvest disease testing, breaking or shortening of dormancy is often needed. Numerous ways for chemical regulation of dormancy period were developed, but the efficiency of such methods is strongly genotype dependent. Recently a comparative study of chemical treatments for breaking tuber dormancy of some new Hungarian potato varieties was carried out. Continuing this work, here we report about the effects of chemical treatments used for breaking dormancy on the number of stems and tubers of progeny plants. The experiment was conducted in three consecutive vegetation period, with three varieties having different maturity type and different dormancy period: Balatoni rózsa, Botond and Démon. Treatments were performed using gibberellic-acid, benzyl-adenine and Rindite in different concentrations and combinations. After the dormancy period, tubers were planted into pots and grown under controlled conditions. Number of developed stems and tubers was counted. According to the results, applied treatments had a large effect on the number of developing stems and tubers of the progeny plants. Combined treatments of Rindite+gibberellic-acid, and gibberellic-acid at 100 ppm increased significantly the number of stems and tubers. Correlation between the efficiency of dormancy breaking and the number of developed tubers was found. Based on our data, Rindite and gibberellic-acid have an important role not only in breaking dormancy, but also in increasing the tuber number/plant. This positive effect could be utilized in seed potato production.