Abstract: Aiming to explore the effects of different concentrations and spraying frequency of chlormequat chloride and mepiquat chloride on the growth and development, fruit yield and quality of Ping’ou hybrid hazelnut, Liaozhen No. 7 was used as the experimental material, with a control group (CK) treated with an equivalent amount of water. The chemical control treatments involved applying different concentrations of chlormequat chloride and mepiquat chloride (diluted 2 000, 1 500, 1 000, 800, and 600 times), and administering these treatments two or three times. The study measured parameters including chlorophyll content, yield(total husk yield, fresh fruit yield, and dry fruit yield), and fruit quality (assessing the longitudinal and transverse diameters of both dry fruits and kernels, kernel weight, and shell thickness). The results showed that the application of chlormequat chloride and mepiquat chloride significantly improved the photosynthesis of the leaves, fruit yield and quality of Ping’ou hybrid hazelnut, and at the same time had a certain inhibitory effect on the current year’s branches and bud spacing. The best yield-increasing effect was achieved by spraying 1 000 times diluted chlormequat chloride solution, which increased by 66.65% compared with CK. The best yield-increasing effect was achieved by spraying 1500 times diluted mepiquat chloride, which was 40.64% higher than that of CK. The results provided a reference for the rational utilization of chlormequat chloride and mepiquat chloride in the production of Ping’ou hybrid hazelnut.

Key words: ping’ou hybrid hazelnut;, chlormequat chloride, mepiquat chloride, yield, fruit quality