EFFECTS OF LONG-TERM WATER STRESS ON LEAF GAS EXCHANGE, GROWTH AND YIELD OF THREE STRAWBERRY CULTIVARS

Drought is one of the most common limiting environmental factors affecting plant growth and productivity. Strawberry is a plant of large demand for water along with a high susceptibility to drought. In the present study, the response of three strawberry cultivars ('Elsanta', 'Honeoye', 'Grandarosa') grown under greenhouse conditions to water deficiency was examined by evaluating the yield and morphological (leaf and root development) and physiological (leaf gas exchange, leaf water potential) parameters. Plants were subjected to two different water regimes: optimal irrigation (control, water potential in the growing medium was maintained at the level of -10 kPa), and reduced irrigation (stress treatment, water potential in the growing medium was maintained at the level of -30 kPa). Genotypes differed in their response to water deficiency. Cultivar 'Elsanta' presented high rates of net photosynthesis with high value of water use efficiency (a ratio of photosynthetic rate to transpiration rate) under water shortage conditions. Water stress affected plant vigor. The weight and total leaf area of the stressed 'Honeoye' plants were considerably reduced as compared to these of the control. No significant differences in weight and root length were observed between the well-irrigated and stressed 'Elsanta' plants, while the root development in two other cultivars was retarded. Under water deficiency conditions 'Elsanta' gave the highest yield whereas 'Honeoye' the lowest. Among examined cultivars, 'Elsanta' appeared to be more drought tolerant which was reflected by both growth and yield parameters.