Effect of root zone cooling on flower development and fruit set of Satohnishiki sweet cherry

Abstract: The effects of root zone cooling on flower development and fruit set of 'Satohnishiki' sweet cherry were studied. Soil temperature in pots of the tree was maintained at approximately 11?C from bud burst until petal fall, then at about 15?C until harvest by circulating cooled water through a tube coiling the pots. Root cooling did not appreciably affect flower size, pollen germination and pollen tube elongation in pistils. However, the treatment prolonged ovule longevity and markedly increased the fruit set rate. These results suggest the possibility of applying root cooling to improve the fruit set of sweet cherries grown in warm regions.