Study on Germination Rate and Viability of Pollen for Castanea henryi

Size and quantity of pollen were measured, and germination rate of pollen at different flowering stage, branches, storage and culture conditions were determined for different cultivars of Castanea henryi. The results showed that there were differences existed in size, morphology, quantity and viability of pollen among different cultivars, and the pollen quantity and viability of No.1 and No.24 were higher, which were suitable for pollination trees. The pollen germination rate in full bloom was much higher than that in initial and end flowering, and the germination rate of pollen from male branch was significantly higher than that from bearing branch. Low temperature with 4-7 ℃ and drying storage condition could prolong the pollen viability. The concentration of sucrose at 5.0%-7.5%, and the concentration of boric acid at 400-900 mg/kg were greatly suitable for pollen germination, and the most suitable temperature for that were from 30 ℃ to 35 ℃. The study suggests that, we should choose sunny weather with higher temperature and spray the boric acid with concentration of 400-900 mg/kg at full flowering stage on production, to promote pollen germination, improve fruit-set rate, and reduce the empty shell.