Abstract
Solid plantings of the hybrid 'Ambersweet' [(Citrus reticulata Blanco (C. paradisi Macf.)×(C. reticulata)×midseason orange (C. sinensis (L.) Osb.)] have had poor yields. The better blocks of 'Ambersweet' typically have yields of 620 to 740 boxes per hectare, while poorer yielding blocks often produce less than 250 boxes per hectare. Reasons for this problem have been attributed to young tree age, over-fertilization, and excessive vigor on some rootstocks. Data collected over 3 years showed that anthers were often shriveled and had few pollen grains, moderate pollen viability and poor pollen germination compared to other cultivars recognized as good pollinators. Pollen germination was better in one of the higher yielding blocks in 1 year. Almost no pollen germination occurred during 1998 tests of flowers collected from commercial 'Ambersweet' trees or some of the USDA Foundation Farm 'Ambersweet' trees used for budwood to plant many of the first commercial trees in Florida. Because of its poor pollen production and low germination, 'Ambersweet' is not a good selfproducer and should not be planted with another cultivar that requires cross-pollination.
