Pesticide Residues And The Effects Of Meteorological Factors On Fruit Quality Of Taizhou Citrus

Safety and high quality are the development direction of citrus industry.Citrus is the largest fruit industry in Taizhou.In order to understand the status of pesticide residues of citrus in Taizhou and explore the effects of meteorological factors on fruit quality of citrus,the pesticide residues were monitored for six consecutive years.At the same time,for analyzing the correlation between fruit quality and meteorological factors in different phenological periods,the fruit quality of citrus were determined for three consecutive years and the meteorological data were collected.All the above provide a theoretical basis for the high-quality development of Taizhou citrus industry.The main findings are as follows:1.The detection of pesticide residues of citrus in Taizhou were generally good.The detectable rate was 91.41%,and the standard-exceeding ratio was 1.04%.A total of 43 pesticides were detectable,and the detectable rate of 12 kinds of pesticides were above 10%.2.The fruit quality of citrus in Taizhou were excellent.Sampling results showed that both citrus unshiu and Hongmeiren citrus have reached the grade of excellent fruit.Bendizao citrus has reached the grade of excellent fruit in addition to TSS in 2018.3.Temperature and heat are important factors affecting the citrus quality.The average annual temperature,the temperature and heat at the physiological fruit-dropping stage were respectively significantly correlated with two quality indexes of citrus unshiu.V_c of Bendizao citrus was significantly correlated with temperature and heat at flowering stage.The temperature and heat at picking stage were significantly correlated with four quality indexes of Hongmeiren citrus.4.The diurnal temperature range is the key factor affecting the flavor of citrus fruit.The larger mean diurnal temperature range has a positive effect on the flavor of citrus unshiu,while the larger diurnal temperature range at the picking period has a negative effect.The larger mean diurnal temperature range at the germination,flowering and physiological fruit-dropping stage makes the flavor of Hongmeiren citrus better.5.Precipitation has an effect on the quality of citrus.There was a significant positive correlation between the total acid of citrus unshiu and annual precipitation.The total acid of Hongmeiren citrus had a significant positive correlation with precipitation at germination stage.6.The sunshine duration of specific phenological period had a significant effect on the quality of citrus.Annual sunshine duration and the sunshine duration at physiological fruit-dropping stage were both significantly correlated with the four quality indexes of Bendizao citrus.There were significant correlations between three quality indexes of Hongmeiren citrus and sunshine hours.