Performance of ' Valencia' Trees on Four Rootstocks at High Density Planting

摘要

The performance of ' Valencia' orange trees on Swingle citrumelo (Swi) ,Cleopatra mandarin (Cleo) ,Milam lemon (Mil) ,and Volkamer lemon (Volk) rootstocks was evaluated on a flatwoods soil in southwest Florida. Trees were planted in a closelyspaced setting (5. 80m x 2. 75m) at a tree density of 627 trees/ha. Leaf mineral concentration, tree growth, fruit yield, fruit quality, and economics were measured and computed 4,7,10,and 12 years after planting. Compared to citrus leaf standards, leaf mineral concentration values were within the optimum to the high range. Yield efficiency expressed as kg solids/m3 of canopy and juice quality in terms of juice content, Brix, and kg solids/box increased with tree age. Tree and fruit sizes were the highest for Volk and the lowest for Cleo. Fruit yield was the highest for Volk 4 and 7 years after planting, but yield expressed in kg solids/ha was not significantly higher for Volk 4 and 7 years after planting due to the higher solids/box for Swi. Fruit yield of trees on Swi surpassed those on Volk 10 and 12 years after planting. Yield efficiency was also higher for Swi than for Volk. Brix,juice content and soluble solids in the fruit were higher for trees on Swi and Cleo than for trees on both lemon rootstocks. Financial analysis showed that at high density planting, trees on Swi were the most profitable.