Analysis Of Physiology And Fruit Quality Difference Of Adult Walnut Under Different Irrigation Quota

Walnut is an important pillar industry of forestry and fruit industry in Aksu region,Xinjiang ,and diffuse irrigation is a main irrigation mode used locally.Because Aksu is located in the Tarim Basin in southern Xinjiang,it has environmental factors such as strong light and less precipitation,and extensive irrigation management and other problems,making the already scarce water resources more tight,and the fruit quality can not be improved.In this paper,the influence of different irrigation quotas on the photosynthetic physiology of’Wen 185’(J.regia’Wen 185’),the main walnut variety in Aksu,provides some scientific basis for the water saving and cost reduction of walnut irrigation in Aksu.This experiment was conducted in the National long-term research base of Xinjiang amu Fruit Tree,with adult’Wen185’walnut tree.The conventional irrigation quota was 2250 m~3/hm~2as the CK irrigation quota,the gradient difference of the irrigation quota was set to 750 m~3/hm~2,and two irrigation gradients were set up and down respectively.The respective irrigation quotas for C1,C2,CK,C3,and C4 were 750 m~3/hm~2,1500 m~3/hm~2,2250 m~3/hm~2,3000 m~3/hm~2,and 3750 m~3/hm~2.The respective irrigation time was set as the first three reproductive periods of walnut with one irrigation time,on May 25,June 28 and July 25.Differences and correlation analysis of leaf area index,chlorophyll a,chlorophyll b,leaf water potential,leaf water content,and leaf relative water content,walnut appearance traits and quality were performed,and each treatment was comprehensively evaluated in combination with principal component analysis.The main study results are as follows:(1)The influence of different irrigation quotas on the photosynthetic physiology of mature walnut.Leaf water potential,leaf water content,and the relative leaf water content showed a significantly linear positive correlation with the irrigation quota,and both the C1 and C2 trees were subjected to drought stress.When the irrigation quota increases to 3,000 m~3/hm~2,continuously increasing the irrigation quota does not enhance the photosynthetic assimilation capacity.Therefore,C3 is the most water-saving treatment to ensure better photosynthesis of the tree body.(2)The influence of different irrigation quotas on the water condition of mature walnut.Leaf water potential and irrigation quota showed a significant linear positive correlation,and both C1 and C2 tree bodies were subjected to drought stress.C4 increased compared with C3 irrigation quota,but the water condition of the tree body did not change significantly,and continuing to increase the irrigation quota did not affect the water condition of the tree body.Therefore,C3 is the most water-saving treatment to ensure the good tree water condition.(3)The influence of different irrigation quota on the aged walnut fruit.When the irrigation quota reaches 2250 m~3/hm~2of CK,increasing the irrigation quota will not have a significant impact on the yield and the size of walnut.Although the irrigation quota of C1 makes the walnut kernel tannin reduced,but the nutritional value is lower than that of C3 and C4,and the yield is the least.With the increase of irrigation quota,the yield of C4 with irrigation quota of 3750 m~3/hm~2did not increase significantly compared with C3,and the tannin content of walnut nuts increased and the nutritional value was reduced compared with C3 treatment with irrigation quota of 3000 m~3/hm~2.Thus the walnut value of C3 was the highest among the 5 treatments.Conclusion:The 3000 m~3/hm~2irrigation quota of C3 is the most water-saving irrigation quota among the 5 highest treatments of walnut value.