Selective Flower Removal Increases Cranberry Fruit Set

Abstract

Selective flower removal was used in 1987 and 1988 to evaluate intraplant competition or inhibition within flowering uprights of `Searles' cranberry (Vaccinium macrocarpon Ait.). The lowest two flowers were removed from uprights at various stages of plant development in 1987. With one or both of the two earliest, i.e., lowest, flowers developing `into fruit, 25% of the remaining flowers matured into fruit. Removal of the earliest two flowers at preblossom or late blossom resulted in ≈ 46% fruit set for the remaining flowers. Slightly fewer upper flowers set (36%) when the earliest flowers and fruit were removed at early fruit development. In 1988, the lowest two flowers were removed at preblossom and natural insect pollination was supplemented by hand pollination. Hand-pollinated (upper) flowers set 58% when the lowest two flowers were removed, compared to 17% for the unthinned control. Yield and fruit numbers were lowered slightly as a result of flower thinning in both years. A significant amount of variation in fruit production was explained by the number of flowering uprights per unit of production area in both years.