ARS | Publication request: BREAKING TUBER DORMANCY WITH SYNTHETIC CYTOKININS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 5, 2004
Publication Date: December 15, 2004
Citation: Suttle, J.C. 2004. Breaking tuber dormancy with synthetic cytokinins [abstract.] American Journal of Potato Research. 82(1):92.

Technical Abstract: At harvest and for an indeterminate period thereafter potato tubers are dormant and will not sprout. In tubers destined for processing, maintenance of tuber dormancy is a critical aspect of successful potato storage. Conversely, rapid termination of tuber dormancy is desirable for certain segments of the potato industry such as seed certification trials and same-season use of seed potatoes for southern markets. Plant hormones play pivotal roles in tuber dormancy control. In particular, cytokinins have been proposed to act as endogenous dormancy terminating agents. Due to rapid metabolic inactivation, the efficacy of naturally occurring cytokinins in agricultural applications is often limited. Synthetic cytokinins are often more stable in planta and exhibit greater biological activities. In this report, the sprout-inducing effects of phenyl-urea and nitro-guanidine type synthetic cytokinins in Russet Burbank mini- and micro-tubers are described. Immediately after harvest, application of ' 10 'g of the phenyl-urea cytokinins N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) or thidiazuron (TDZ) and a phenyl-nitroguanidine cytokinin (NG ) had no effect on tuber sprouting. As the length of storage increased, all cytokinins exhibited a dose-dependent stimulation of tuber sprouting with the order of activity being: NG ' CPPU > TDZ. At all times tested, both NG and CPPU were more effective than zeatin in breaking tuber dormancy. Preliminary studies have indicated that micro-tuber dormancy can also be terminated using these cytokinins. The effects of these treatments on endogenous dormancy-related hormones are under investigation and will be described.