A Set of Artificial Pollination Technical Measures: Improved Seed Yields and Active Ingredients of Seeds in Oil Tree Peonies

The tree peony, a novel woody oil crop extensively cultivated in China, necessitates further investigation into artificial pollination technology to enhance seed yield. In this study, we conducted artificial pollination experiments with 6-year-old Paeonia ostii ‘Feng Dan’ seedings for suitable pollen sources, pollen concentration, pollination timing, and pollination frequency. By evaluating seed yields, active ingredients, and oil quality, we derived the following significant conclusions. Firstly, compared to natural pollination, artificial pollination could significantly increase the fruit diameter by 13.94–27.58%, seed yields by 35.17–58.99%, and oil content by 6.45–7.52% in tree peonies. In active ingredients, seeds produced by pollen from Hantai County significantly enhanced starch content (by 48.64%), total phenols (by 41.18%) and antioxidant capacity (by 54.39%). In oil quality, seeds produced by pollen from Heyang County exhibited the highest α-linolenic acid and total fatty acid content with enhancements of 1.68%, 7.41%, and 8.48%. Secondly, hand pollination with pure pollen significantly increased seed yield by 58.99%, total phenol content by 40.97%, antioxidant capacity by 54.39%, and oil content by 1.53% compared to natural pollination. Thirdly, pollination at 2/3 bloom range significantly increased seed number by 63.08% and yield by 45.61% compared to natural pollination. Finally, the effect of one, two, and three pollination events had no difference in seed yield. So, to summarize, applying a 100% concentration of allochthonous pollen once is recommended when the bloom range is more than two thirds.