Effect of gibberellic acid on dormancy breaking of Agria potato seed mini-tubers

In order to study the effect of gibberellic acid on potato mini-tubers, Agria cultivar, newly produced mini-tubers from healthy and diseases free seedlings were studied at four seed size groups (8-, -7, 8- and less than 8 mm) after treating with 000 ppm gibberellic acid in different sampling dates (0, 40, 60, 90 and 0 days after treating with gibberellic acid). Experimental design was completely randomized design based factorial with three replications. Number of days from treating with gibberellic acid to sprouting was considered as dormancy period. Other traits such as number of days to emergence, number of germinated mini-tubers, sprouting percentage and length of buds were measured. Results showed that there were significant differences among gibberellic acid treated and non-treated, different seed size groups, different sampling dates and those interactions for all traits. The earliest sprouting, the most sprouting percentage and the longest sprouts were observed in 8- mm seed size group. Therefore it was concluded that gibberellic acid caused decreasing dormancy period of mini-tubers from 90-0 to 40-60 days. Also, the smaller mini-tubers were the late sprouting and had short sprouts.