The Effect of High Temperature Occurring in Subsequent Stages of Plant Development on Potato Yield and Tuber Physiological Defects

Potato (Solanum tuberosum L.) is characterized by specific temperature requirements and develops best at about 20 A degrees C. High temperatures during the growing season cause an array of changes in potato plants, which affect its development and may lead to a drastic reduction in economic yield. In natural conditions drought and heat stress are two different types of abiotic stresses that occur in the field simultaneously or separately, in the case of irrigation use on potato plantations. The aim of this work was to assess the response of six potato cultivars to high temperature during the subsequent stages of plant growth under conditions of good soil moisture and drought. The pot experiment was carried out with the cultivars: Aruba, Desir,e, Etola, Finezja, Flaming and Tetyda. The impact of high temperature day/ night 35 A degrees C/25 A degrees C on potato plants was tested in three periods: June 16-30, July 1-15 and July 16-30. In these periods half of the plants were watered to a level close to optimal, while the other half remained without irrigation. Final harvest was performed after full maturity of plants in the control combination. Our studies confirm the view that potato productivity is greatly reduced at temperatures higher than optimum. Here we demonstrated that tested potato cultivar's response to high temperature during the growing season is dependent on the growth stage. The earlier a heat occurs, the more negative its impact on the growth and total yield of potatoes. The results obtained in this study indicate that among the tested cultivars 'Tetyda' was the most tolerant to high temperature acting on the plants during the growing season. Our research shows that the total yield is not the only indicator of potato tolerance to high temperature during the growing season, but the assessment should also take into account the occurrence of secondary tuberization and physiological defects of tubers.