No abstract

No abstract

Citrus growers in Australia need to be able to produce large fruit size for premium returns in domestic and overseas markets. Therefore, it is important to manipulate the tree canopy by hedging in a "heavy-flowering" year to decrease crop load and enhance fruit size the following year. A two-year study was conducted on the relationship of fruit size to different inflorescence types that developed on bearing branch units (BBU) that developed in the summer following mechanical hedging during flowering in spring compared with non-hedged branches. Spring hedging produced a "stronger" vegetative growth flush compared to the non-hedged branches: BBU developing on hedged branches produced more sprouts, flowers, leafy inflorescences and 3.6 to 5 mm larger fruit size than BBU from non-hedged branches. Moderate severity mechanical hedging in the spring of "on-flowering" years is recommended as a practical means to manage the existing crop load, enhance fruit size and alleviate alternate bearing for the following year.

No abstract

Citrus growers need to be able to determine the expected fruit size and the proportion of export-quality fruit at harvest relatively early in the growing season. Early fruit size prediction would also help in planning harvest operations and administering marketing strategies well in advance. This will also enable growers to remove small fruits that would not attain the desired export size. Fruit diameter growth of 'Washington Navel' oranges was measured over three consecutive growing seasons during the Stage II (cell enlargement) period between January and July. Fruit were randomly selected from around the tree canopy and tagged to measure the fruit diameter at fortnightly intervals until harvest. The data were used to develop a fruit size prediction model using cubic smoothing splines. The model was able to predict the final fruit size and the final percent size distribution at early stages of fruit development in January/February in Australia. Results indicated that under the growth patterns shown by navel oranges, accurate predictions of the final fruit size and fruit size distribution were possible during early Stage II fruit development phase 5-6 months ahead of the final harvest.