Chinese chinquapin (Castanea henryi (Skam) Rehder & Wilson) is an ecologically and economically
important nut tree species in southern China. Chinquapin suffers from high rates of
empty shells, which are directly related to low pollination efficiency. Efficient pollination mainly
depends on pollen vigor, which depends on the pollen grain germination rate and the rate of pollen
tube growth. We studied the pollen germination rate and pollen tube length of the advanced chinquapin
cultivar HCHJA-1; specifically, we compared the effectiveness of different concentrations
of 3 key factors by an orthogonal design method: boric acid (H3BO3), calcium chloride (CaCl2),
and gibberellic acid (GA3), to determine pollen vigor and optimize the culture medium for in vitro
pollen germination. Results indicated that chinquapin pollen germination rates were significantly
affected by medium components. The pollen germination percentages varied between 13.02 and
66.99%. Three factors influenced pollen germination in the order of decreasing significance:
GA3 > H3BO3 > CaCl2. Pollen tube growth was influenced by these factors as follows: H3BO3 > GA3
> CaCl2. The optimal culture medium for promoting pollen vigor of C. henryi HCHJA-1 was 1%
agar, 10% sucrose, 20 mg L-1 GA3, 100 mg L-1 H3BO3, and 50 mg L-1 CaCl2.