Investigation And Analysis Of The Causes Of Seed Coat Browning Of ’Wen 185’ Walnut Seed Kernels In Aksu Region

The present study focused on Xinjiang Aksu region（Alar City,Wensu County and Awati County）,which is a high-quality production area of ’Wen185’ walnuts in China,and based on the basic situation of’Wen185’ walnut production in Aksu region,we investigated and analyzed the causes of seed coat browning of ’Wen185’ walnuts.’Wen185’ walnut nut seed kernel seed coat browning causes were investigated and analyzed in order to obtain scientific data to improve the appearance quality of kernels and provide technical reference for ’Wen185’ walnut quality improvement in the region.The main results are as follows.（1）The survey found that the nut bearing orientation was related to the degree of seed coat browning of ’Wen185’ walnut nuts.When the nut bearing orientation was due south,the light intensity was strong,the color parameter light and dark value L*,yellow and blue value b* were high,and the browning rate of the nuts was low,while when the nut bearing orientation was inward,the light intensity was weak,the color parameter L* and b* were low,and the browning rate of the nuts was high;the light intensity was significantly and positively correlated with the color parameter L* of the seed kernel seed coat,and the correlation coefficient R was 0.9551*.（2）It was found that there was variability in the degree of nut seed kernel seed coat browning in different ’Wen185’ walnut test orchards in Aksu region.More than 85% of the nuts with light yellow and light amber seed coats were found in ’Wen185’ walnut test orchards in Awati and Wensu counties,and the degree of nut browning was low,while 17.78% of the nuts with amber seed coats were found in ’Wen185’walnut test orchards in Alar City The degree of browning of the nuts was high.The highest values of L* and b* were found in Wensu County with 39.82 and 28.57,respectively,and the highest values of a* and color ratio h were found in Awati County with 5.86 and 0.30.The degree of browning of the seed kernel seed coat of ’Wen185’ walnuts in the Aksu region was from low to high in Wensu County,Awati County,Alar City,and Alar City,respectively.The degree of browning of ’Wen185’ walnut seed kernels in Aksu region was from Wensu County,Awati County,and Alar City in descending order.（3）’Wen185’ walnut test orchard B1,Soil N,P,and K contents affected ’Wen185’ walnut nut seed kernel seed coat color parameters and nut browning rate.The degree of seed coat browning of ’Wen185’walnut nuts seed kernels was highly significantly and positively correlated with soil effective phosphorus and fast-acting potassium,with correlation coefficients R of 0.8553** and 0.9042**,respectively,and with soil alkaline decomposition nitrogen,with correlation coefficient R of 0.7065*.High soil N,P and K content,strong tree strength and low nut browning.（4）’Wen185’ walnut test orchard A1,Variability in seed kernel seed coat color parameters and nut browning rate of ’Wen185’ walnut nuts at different picking stages.Early picking resulted in low nut browning;late picking resulted in high nut browning.The analysis concluded that the optimum picking period was August 30,2021-September 10,2021.（5）The polyphenol content in the seed kernel seed coat of ’Wen185’ walnuts was correlated with the degree of browning;the higher the polyphenol content,the higher the color parameters L* and b*,and the lower the browning rate.There was a highly significant positive correlation with color parameters L* and b*,with correlation coefficients R of 0.8434** and 0.8183**,and a significant negative correlation with color ratio h and red-green value a*,with correlation coefficients R of-0.7537* and-0.6797*.The results showed that light intensity,regional environmental factors,soil nutrients,and harvesting period were correlated with the browning of seed coat of ’Wen185’ walnut nuts,and that enhancing canopy ventilation and light penetration,increasing soil water content,improving soil nutrient content and harvesting at the right time could help reduce the browning of seed coat of ’Wen185’ walnut nuts.In production practice,we can target these factors to reduce the browning of the seed coat of ’Wen185’ walnut seed kernels.