Decapitation of potato plants in conditions of Karelia

The effectiveness of plants decapitation of potato varieties Nevsky and Nida was examined at a critical period of their development (budding - mass flowering) during three field seasons distinguished by different weather factors in the conditions of Karelia. The plants with removed apical part of the stems (5 cm) were compared with control samples of intact plants. The research results showed that in the North with a short growing season (average 70 days) the decapitation of plants of the studied species caused an increase in their assimilation surface, as well as the decrease of potato yield by 18,0 %. Significant decrease of tubers susceptibility to black scurf and silver scurf has been established, probably due to the change in the level of phytoalexins in plants with a mechanical destruction of the stems apical part.