Effective Pollination Period of ‘AU Golden Sunshine’ (Actinidia chinensis) and ‘AU Fitzgerald’ (A. deliciosa)

The marketable yield and profitability of kiwifruit production is closely associated with successful pollination. Commercial kiwifruit production often involves much effort to enhance pollination due to the inherent difficulties associated with functionally dioecious plants with flowers that do not produce nectar. Determining the length of time that female flowers can be successfully pollinated would aid management decisions. Therefore, the purpose of this research was to determine the effective pollination period (EPP) for Actinidia chinensis ‘AU Golden Sunshine’ and A. deliciosa ‘AU Fitzgerald’. In 2013, 30 female flowers (n=30) that had been previously isolated/bagged for each cultivar were hand pollinated each day by direct flower-to- flower contact with the male pollinizer, and re-bagged to prevent open pollination. ‘AU Golden Sunshine’ flowers were pollinated 1, 2, 3, 4, and 5 days after anthesis (DAA) and ‘AU Fitzgerald’ flowers were pollinated 1, 2, 3, 4, 5, and 6 DAA. Anthesis was considered the day the flower opened. In 2014 and 2015, the same procedures were followed as the year before but with slight modifications: 32 female flowers (n=32) were hand pollinated with harvested male pollen each day with a camel hair brush and the flowers were pollinated for 1, 2, 3, 4, 5, 6, and 7 DAA. Results for the EPP determination of ‘AU Golden Sunshine’ suggests that for successful fruit set, flowers should be pollinated within 5 to 6 DAA. However, fruit with the greatest size, weight and seed number was realized when pollinated within 3 DAA for years 1 and 2 and within 5 DAA for year 3. For ‘AU Fitzgerald’, fruit set declined at 5 DAA for the first year (2013) suggesting that the EPP was 4 DAA. In the second year (2015), fruit set remained consistently high over the 7-day period, though fruit weight, size, and seed number declined 5 DAA. Flower production and fruit set for ‘AU Fitzgerald’ was prolific in 2015, suggesting that the EPP was affected by the biennial nature of the species.