Analysis of different tree structures for light response and the difference of main economic traits in <italic>Camellia oleifera</italic>

<bold>Objective</bold> This study aims to investigate the effects of different tree structures on yield and quality of <italic>Camellia oleifera</italic>，thus providing reference for the screening of suitable tree structures and efficient cultivation of <italic>C. oleifera</italic>. <bold>Method</bold> With the <italic>C. oleifera</italic> varieties ‘Huashuo’ and ‘Huaxin’ as research objects，the light distribution，photosynthetic characteristics，leaf quality（water content，specific leaf area，leaf thickness，chlorophyll content），main economic traits of fruits（single fruit mass，single fruit fresh seed mass，single fruit dry seed mass，fresh seed rate，dry seed rate，fruit shape index and yield）and oil quality（palmitic acid，stearic acid，oleic acid，linoleic acid，linolenic acid，arachidonic acid）of <italic>C. oleifera</italic> with different tree structures were measured and analysed. <bold>Result</bold> The relative light intensity of the two improved varieties of <italic>C. oleifera</italic> in the tree structure of the open center shape and the natural round head shape was as follows：the upper peripheral &gt; the lower peripheral，the upper inner chamber &gt; the lower inner chamber，the upper peripheral &gt; the upper inner chamber，the lower peripheral &gt; the lower inner chamber，showing the law of decreasing step by step from top to bottom and from outside to inside.Among different tree structures，the open center shape was higher than the natural round head shape.In terms of photosynthetic characteristics，the net photosynthetic rate of the upper and lower layers of the two <italic>C. oleifera</italic> varieties was significantly different，with open center shape &gt; natural round head shape.In terms of fruit economic traits，the tree structure had the most significant effect on the yield of <italic>C. oleifera</italic>.The yield per plant of ‘Huashuo’ with open center shape and natural round head shape was 6.72 kg and 4.98 kg，respectively.The yield per plant of ‘Huaxin’ with open center shape and natural round head shape was 6.62 kg and 4.25 kg，respectively.The yield per plant and canopy yield of the two improved varieties of <italic>C. oleifera</italic> were open center shape &gt; natural round head shape，but there was no significant differences in kernel oil content and oil composition.The relative light intensity was significantly positively correlated with the yield per plant（<italic>r</italic>=0.58**），and the net photosynthetic rate was significantly positively correlated with the yield per plant（<italic>r</italic>=0.69**），respectively.The relative light intensity was significantly positively correlated with the net photosynthetic rate，and the correlation coefficient was 0.52. <bold>Conclusion</bold> Under natural conditions，the light distribution of the open-center tree of ‘Huashuo’ and ‘Huaxin’ was more scientific due to its higher light energy utilization efficiency as well as higher yield and quality.