Wpływ wysokiej temperatury i suszy podczas wegetacji na długość okresu spoczynku bulw ziemniaka (Solanum tuberosum L.)

Celem artykułu było określenie wpływu wysokiej temperatury w różnych okresach wegetacji na długość spoczynku bulw wybranych odmian ziemniaka, których rośliny rosły w warunkach suszy i dobrej wilgotności gleby. Doświadczenie wazonowe zostało przeprowadzone w hali wegetacyjnej i komorach wegetacyjnych. Badano wpływ wysokiej temperatury dnia/nocy 35°C/25°C na rośliny ziemniaka w trzech 14-dniowych okresach, od połowy czerwca do końca lipca. Połowa roślin była podlewana do poziomu zbliżonego do optymalnego (FSM), a druga połowa została poddana warunkom narastającej suszy glebowej (SD). Bezpośrednio po zbiorze bulwy umieszczano w warunkach sprzyjających kiełkowaniu. Wykazano, iż długość okresu spoczynku bulw ziemniaka była istotnie mniejsza, gdy wysoka temperatura oddziaływała na rośliny w warunkach narastającej suszy glebowej. Różnica dla badanych odmian wynosiła średnio 13 dni. Po oddziaływaniu wysokiej temperatury w drugim i w trzecim okresie spoczynek był o 25-28 dni krótszy niż w okresie pierwszym. Wiązało się to ze stadium rozwojowym tworzących się i rosnących bulw.

Potato (Solanum tuberosum L.) is characterized by specific temperature requirements and develops best at about 20°C. High temperatures during the growing season cause an array of changes in potato plants, which affect its development. 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 tuber rest period of potato cultivars depending on high temperature during the subsequent stages of plant growth under conditions of good soil moisture and drought. The pot experiment was carried out in a greenhouse and in a growth chamber, over the course of two years. The following early cultivars were tested: Flaming, Aruba, Etola, Finezja, Tetyda and Desirée. The impact of high temperature day/night 35°C/25°C on potato plants was tested in three periods: I-June 16-30, II-July 1-15 and III-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. The Control combination consisted of potato plants grown throughout the whole season under conditions close to optimal. Final harvest was performed after full maturity of plants in the Control combination, between August 16 and 25. The study of tuber rest period was performed according to the methodology of Physiology Section of EAPR. It was found a highly significant effect of the examined factors on the potato tuber rest period. It was demonstrated here that this period was significantly shorter than high temperature was acting under drought conditions than under soil moisture conditions favourite for plants. The effect of high temperature on the rest period was dependent on the time in which this temperature affected potato plants. After action of high temperature in the second and third period the dormancy was shorter by 25-28 days than in the first period. Among the tested cultivars the medium early Desirée was characterized by the longest rest period in the Control combination and other medium early cultivars Finezja and Tetyda by much shorter dormancy. This confirm the fact that the potato tuber rest period is not closely related to the length of the growing season. The high correlation between tuber rest period in Control and tuber rest period after high temperature acting proves that the rest period of tubers is a genetic trait and a degree of its modification depends on this trait. The effect of high temperature acting on plants during growing season on potato tubers rest period depends mainly on the plant development stage.