Pollen Tube Growth In Compatible and Incompatible Pear Genotypes

Pollination compatibility between cultivars is essential for pear cultivation, production and breeding programs. In recent years, many new elite pear cultivars, such as ‘Cuiguan’, ‘Xizilv’, and ‘Lvbaoshi’, were bred in China. To provide functional data for further breeding work, we studied pollen tube growth in styles with fluorescence microscopy in two cross combinations ‘Cuiguan’ (S₃S₅) × ‘Lvbaoshi’ (S₁S₄) and ‘Xizilv’ (S₁S₄) × ‘Lvbaoshi’ (S₁S₄) in this work. The results showed that ‘Cuiguan’ × ‘Lvbaoshi’ was compatible and the other one was incompatible via observation on pollen tube growth in styles. Pollen grains in both cross combinations could germinate on the stigma, while germination of pollen grains in incompatible pollination was slower than that of compatible pollination. Pollen grains in incompatible pollination geminated on the surface of stigma in two hours after pollination, whereas pollen tube stopped growth at the 1/3 location away from stigma after eight hours and the tip of which expanded into sphericity. In contrast, pollen grains in compatible pollination geminated in one hour after pollination, and the pollen tube elongated to the middle parts of style after eight hours, entered ovary after 24 hours, reached into embryo sac after 48 hours, and double fertilization was finally completed after 72 hours. Growers could plant different pear genotypes in their orchard based on our findings.