Study On The Optimal Suspension Of Gala Pollen For Spray Pollinating

Generally, apple needs insects for pollinating fully and fruit setting well, because of the obvious self-infertility. Recently, with the development of large-scale agriculture and the increasing demand in agricultural industrialization, natural habitat and breeding environment of insects have been artificially broken. These changes led to the sharp decline in the number of wild pollinating insects, which can’t suffice the demand of large-scale planting in apple. In order to improve the yield and quality of apple, we should solve the problem of the insufficient in orchard’s pollination and fertilization. Spray pollinating is a widely-used method of artificial pollination mode due to the advantages of fast speed and high efficiency.In this study, we cultured Gala pollen by liquid culture to get the optimal suspension formula for pollen germination and pollen tube growth of Gala. Then, we carried out spray pollinating experiment in an orchard of Luochuan Apple Experiment Station. After investigating the fruit-setting rate and measuring the fruit quality, we got the best method for spay pollinating of Gala. The results were as follows:1. The pollen germination and pollen tube growth of Gala were promoted by adding boric acid(H3BO3), calcium chloride(CaCl2·2H2O), urea, polyethylene glycol(PEG-3350)and sucrose in culture medium. These promoting effects showed the trend of first strengthening and then weakening along with the rise of these components’ concentration.The optimum medium components for Gala pollen were 0.03% H3BO3, 0.03% CaCl2·2H2O,0.3% urea, 15% PEG-3350 and 8% sucrose.2. Accompanied by gradually pH rising in culture medium, pollen germination and pollen tube growth showed the trend of first rising and then declining. The optimum pH of culture medium was 6.5. With the increasing of culture temperature, pollen germination and pollen tube growth had the tendency of first increasing and then declining. The optimum temperature for Gala pollen culture was 25~30℃.3. Spray pollinating suspension added urea could improve the fruit setting rate of Red Fuji. When added 0.3% urea in suspension(30 g urea was added in basic suspension), Red Fuji had the highest fruit setting rate, which was consistent with the result of pollen culture.When spray pollinating, mixed pollen of Qinguan and Starking Delicious could improve the fruit setting rate of Red Fuji.4. Spray pollinating had the significant effects on reducing the skew ratio and skew index of Red Fuji. Seeds number and fruit weight in spray pollinating groups exceeded the control group. Spray pollinating suspension with xanthan gum performed better in reducing skew index and skew ratio of Red Fuji.5. The effects of spray pollinating and adding xanthan gum and urea in suspension were not obvious on internal quality indexes of Red Fuji.