Abstract:

The paper aims to scientifically guide the artificial pollination for passion fruit and solve the problem of passion fruit flowers not bearing fruit. The experiment utilized ‘Fujian Passion Fruit No.1’ as the test material to evaluate temporal changes in pollen viability and stigma receptivity across developmental stages. Pollination treatments were designed with three pollen quantities (small: H1, medium: H2, large: H3) and three stigma retention levels (one: Z1, two: Z2, three: Z3). Excess stigmas were excised during manual pollination. Fruit development was quantified by measuring longitudinal and transverse diameters, and the impacts on pollination and fertilization outcomes were statistically analyzed. The pollen viability peaked 1 hour prior to flowering, followed by a continuous decline, with a significant reduction at 2 hours after flowering. Stigma receptivity reached maximal levels 1 hour after flowering and declined sharply at 3 hours after flowering. Fruit development exhibited a positive correlation with pollen quantity: increasing pollen loads resulted in progressive increases in longitudinal (7.22%-10.72%) and transverse (6.82%-13.38%) diameters (H1 vs. H2/H3; P<0.05), alongside a marked reduction in pollination failure rates (H1: 26.67%; H2/H3: 0%). Under medium pollen quantity (H2), fruits with one retained stigma (Z1) displayed severe developmental impairment, with longitudinal and transverse diameters reduced by 24.06%-24.32% and 25.56%-26.29%, respectively, compared to Z2 and Z3 (P<0.05). No significant differences were detected between Z2 and Z3. Pollination and fertilization failure rates for Z1 were 11.8% and 29.4%, respectively, whereas Z2 and Z3 exhibited no such deficiencies. All H1-H3 treatments achieved 100% fertilization success, indicating that visible pollen deposition on stigmas eliminated fertilization failure. The results showed that the optimal pollination conditions for ‘Fujian Passion Fruit No.1’ occur within 1 hour after flowering, and the pollination meets more than 2 stigmas and reaches the medium pollen amount, which can effectively mitigate risks of pollination and fertilization failure.

Key words: pollen amount, stigma number, pollen activity, stigma activity, pollination, fertilization, ‘Fujian Passion Fruit No.1’