Abstract: Taking vegetable sweet potato varieties (Ipomoea batatas L.) Fushu 18, Eshu 10 and Huangjinye as test materials, the effects of different shading degrees on yield, physiological indexes and photosynthetic parameters of vegetable sweet potato were investigated by simulating photovoltaic agricultural conditions with 0(CK), 30%, 50% and 70% shading treatments on the twentieth day after planting. The results showed that, with the increase of shading degree, the shoot tip yield of three kinds of vegetable sweet potato decreased significantly, and shading had a significant negative impact on the yield of vegetable sweet potato. Among them, Eshu 10 had a obvious yield advantage. Shading had a significant effect on the photosynthetic response and chlorophyll content in vegetable sweet potatoes. With the increase of shading degree, the total chlorophyll content of the three kinds of vegetable potatoes increased and the net photosynthetic rate decreased. Among them, Eshu 10 had a higher photosynthetic rate and total chlorophyll content under severe shading, indicating that Eshu 10 had stronger adaptability to shading environment. In general, moderate shading was beneficial to the increase of sucrose content in vegetable sweet potato, while severe shading affected the accumulation of sucrose, and shading was not conducive to the accumulation of soluble sugar and starch. Shading at 30% and 50% was beneficial to the accumulation of total phenolics, total flavonoids and chlorogenic acid in vegetable sweet potato, and Eshu 10 obtained higher phenolic content under moderate shading. The results of this study indicated that Eshu 10 was more suitable for planting under the agricultural photovoltaic complementary mode.

Key words: vegetable sweet potato (Ipomoea batatas L.), shading, growth and development, quality traits, photosynthesis