Spatio-temporal effects of canopy microclimate on fruit yield and quality of Sapindus mukorossi Gaertn

Canopy microclimate strongly influences fruit growth and development, but little is known regarding the specific responses between different microenvironment of canopy and fruit yield-quality characteristics. In order to reveal the effect of canopy microclimate on Sapindus mukorossi fruit yield and quality, the spatio-temporal distributions of microclimate factors and fruit yield-quality characteristics were investigated. Based on the correlation between fruit yield-quality characteristics and microclimate factors, optimal regression models were established to obtain the suitable canopy microclimate conditions for fruit growth and development and to predict fruit yield and quality. In this study, the spatio-temporal distribution of microclimate factors in canopy was significantly different due to the influence of external environment and canopy structure. There were also significant differences in spatial distribution of fruit yield. Fruit characteristics were closely related to canopy microclimate, which improved from bottom to top and from the inner to periphery. They had positive correlations with light intensity and temperature, but negative correlations with relative humidity. Fruit yield and quality had higher correlation coefficients with canopy microclimate from July and October, which indicated that this period was important for fruit growth and development. And the optimal regression equations were more suitable for the evaluation of fresh fruit yield, dried fruit yield and oil yield as the mean R-2 values were 0.741, 0.737 and 0.701, respectively. Additionally, the calculation results of optimal regression equations showed the suitable microclimate conditions: light intensity is higher than 71 x 10(3) Lux, temperature is between 26-31 degrees C, relative humidity range is 63-76%.