In order to evaluate the efficiency of giberellic acid, carbon-disulphide, and 2-4 chloro-ethyl phosphonic acid (EthrellR) on dormancy breaking and yield of potato cv. 'Marijke', an essay was conducted at Piraí do Sul, PR, Brazil, during 1990/1991. The superiority of the EthrellR treatment over giberellic acid and carbon-disulphide, and its easy application, justify its use for dormancy breaking of potato tubers, for the studied genotype and location, at the rate of 842 mg.L-1, resulting in a potato yield of 23,395 kg/ha.
Solanum tuberosum; potato; growth regulator; plant physiology
