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 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, Desirée, Etola, Finezja, Flaming and Tetyda. The impact of high temperature day/ night 35°C/25°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.Resumen La papa (Solanum tuberosum L.) se caracteriza por requerimientos específicos de temperatura y se desarrolla mejor a cerca de 20°C. Las altas temperaturas durante el ciclo del cultivo causa un arreglo de cambios en las plantas, que afecta su desarrollo y pudiera conducir a reducción drástica en el rendimiento económico. En condiciones naturales la sequía y el agobio térmico son dos tipos diferentes de agobios abióticos que se presentan en el campo simultáneamente o por separado, en el caso de siembras de papa de riego. El propósito de este trabajo fue evaluar la respuesta de seis variedades de papa a la alta temperatura durante los estados subsecuentes de crecimiento de la planta bajo condiciones de buena humedad del suelo y bajo sequía. El experimento en macetas se desarrolló con las variedades Aruba, Desirée, Etola, Finezja, Flaming y Tetyda. Se probó el impacto de la alta temperatura día/noche 35°C/25°C en plantas de papa en tres períodos: junio 16-30, julio 1-15 y julio 16-30. En estos lapsos la mitad de las plantas se regaron a un nivel cercano a lo óptimo, mientras que la otra mitad permaneció sin riego. La cosec...

Potato crop is the fourth main food crops in the world after maize, rice and wheat. It is characterized by specific temperature requirements and develops best at about 20˚C. Forecasts of global warming prompt us to study the tolerance of potato genotypes to heat during the growing season. The aim of this work was to assess the response of chosen potato cultivars to high temperature during the different stages of plant growth under conditions of good soil moisture and drought. The impact of high temperature 32˚C/25˚C on potato plants was determined in pot experiment in three growth stages. A main measure of tolerance of the potato cultivars to high temperature during the growing season was an evaluation of the yield in relation to the Control combination. Here we demonstrated that tested potato cultivar's response to high temperature during the growing season is dependent on the growth stage. The earlier it occurs, the more negative its impact on the growth and yield of potatoes is.

Minituber production by traditional method is an expensive procedure due to limited productivity. In order to increase the multiplication rate of seed material in vitro, multiple techniques have been assayed in the last decades. The aeroponic system is a soilless culture system, where roots are kept in a dark environment saturated with aerosol of nutrient solution. Aeroponics technology is potentially efficient for specific potato cultivars. The aim of this study was to investigate the multiplication rate of microtubers of national cultivars in aeroponics while maintaining weekly intervals between harvests. The total number of harvests was 14 to 15 depending on year. The results of the experiments were analysed with ANOVA and means were separated with the Tukey's test at 5% P-value. The most important parameter of minituber production, their number, was on average 32.5-36.0 per plant and 1268-1396 per m 2 depending on cultivar. Number of minitubers was two to three times greater in the case of aeroponic production than by traditional method. A full economic analysis is necessary to prove that this production technique can be put into practice.Keywords: differentiated systems of potato seed production; in vitro seed material; Solanum tuberosum L.

Potato (Solanum tuberosum L.) is a plant typical mainly for temperate climate and develops best at about 20°C. Heat stress due to increased temperatures is an agricultural problem in many areas in the world. The aim of our work was to assess the response of selected new potato cultivars to heat and drought stress during the subsequent stages of plant growth starting from buds forming. The pot experiment was carried out over the course of two years with the following early cultivars: Lord, Miłek, Gwiazda, Hubal, Oberon and Tetyda. The impact of heat (38°C/25°C) and drought stress on potato plants was tested in four periods of two weeks. In these periods half of the plants were watered to a level close to optimal while the other half remained without irrigation. Our studies demonstrated that tested potato cultivars’ response to heat stress depends on the growth stage, in which the temperature acts on the plants and on the soil moisture. Besides the decrease in yield and tubers’ diminution, the biggest problem was the presence of tubers with physiological defects, particularly of immature tubers. The response of cultivars was differentiated.

The aeroponic system is a viable technological alternative for potato minituber production within a potato tuber seed system. The aim of the study was to evaluate the productivity of potato minitubers grown in aeroponic culture and collected in 14 successive periods of the growing season. The minitubers of cvs. Ametyst and Tajfun were tested in an experimental field after a storage period. It was found that cv. Ametyst was characterized by higher yield and number of tubers than cv. Tajfun. Yield of cv. Ametyst averaged 42.6 t/ha, and cv. Tajfun 37.3 t/ha. The number of tubers over 3 cm of cv. Ametyst averaged 644.2 per ha, and cv. Tajfun 437.7 per ha. The yield and number of tubers was dependent on the physiological age of minitubers harvested on successive dates. Comparing the productivity of minitubers grown in aeroponics and in the soil, a significant difference was found in the number of tubers with a transversal diameter over 3 cm. There were more daughter tubers from minitubers grown in soil. They are the result of different-size minitubers used for planting, smaller ones from aeroponics and larger from soil.