S11 - Session P3 - Drought stress affects productivity and fruit size of new apple cultivars

Authors: Pavol Suran *, Gabriela Pravcova

Apple growing in some regions may be limited due to drought, the apple is a crop sensitive to drought stress. In orchards is necessary to supply enough water in the critical period, especially in the development of fruits. Otherwise, a lack of water results in a reduction of yield. To ensure fruit quality and yield, it is better to prevent drought by irrigation, but irrigation water is not an unlimited resource. For this reason, this work deals with the evaluation of the production of several apple cultivars at a reduced total precipitation. Growth and yield parameters were evaluated in 13 apple cultivars. 'Golden Delicious' were used as a control cultivar. Trees were grafted on M 9 rootstock and planted at density of 2272 trees/ha in Eastern Bohemia (Czech Republic) in 2014. The trees were left without an irrigation system. Date of flowering was recorded for each single tree and at the end of the vegetation girt of trunk was measured to determine the trunk cross-sectional area (TCSA - cm 2 ) at height of 0.6 m. Fully matured fruits of individual varieties were harvested. The total harvest of each tree (kg) was recorded, from which the specific productivity (kg/cm 2 ) was determined, and the fruits were divided into 4 size fractions (-65 mm, 65-75 mm, 75-85 mm, 85+ mm). In apples 'Topaz', 'Flordika', 'Frosta', 'Reluga', 'Gala' and 'Rucla' were evaluated significant higher cumulative yield compared to 'Golden Delicious'. These cultivars seemed to be the most suitable for growing in lack of supplemental irrigation.