Relationships between distribution of relative light intensity and quality in ‘Yueshuai’ apple with different fruit loads
ZHANG Xiumei
WANG Hong
LIU Zhi
YU Nianwen
Abstract：[Objective] Sparse planting with vigorous large canopy used to be the major planting system in apple orchards around the Bohai Gulf.After the trees entered the full bearing age,they had numerous branches and canopy became dense,which reduced fruit quality.Therefore,there is an urgent need to find out the effect of fruit load on light condition and fruit quality.We took‘ Yueshuai’,a hybrid of ‘ Golden delicious’ ב Starking delicious’ bred by Liaoning Research Institute of Pomology,as the experiment material to study the effect of fruit load on the amounts of branches and buds,light conditions and fruit quality.[Methods] For measurement of light intensity,we used gird method,where the canopy was divided into layers of 0.5 meter height per side.A TSE-1332 type digital illumination meter was used to measure light intensity at different layers and orientations.For the measurement of fruit color values,we needed to take samples at different canopy positions,including ＜ 1.0 meter,1.0 to 2.5 meters and ＞2.5 meters in vertical direction and at the center (less than 1.0 meter from the trunk) and periphery (1.0-2.5 m from the trunk) in horizontal direction.A CR 400 colorimeter of Monolta Konica was used to measure fruit colors at different fruit positions.A GY-1 handheld sclerometer was used to measure rigidity and a PAL-1 digital refractometer made in Japan was adopted to measure the content of soluble solids.Sodium hydroxide titration was applied to quantify acid content and 2,6-dichlorophen indophenols method for vitamin C content.Statistical software such as Origin 8.0,excel and DPS were used to process the experimental data and one-way analysis of variance to test the significance of differences among treatments.[Results] Treatment Ⅲ with a fruit load of 1 881.81 had the largest number of branches,followed by treatment Ⅱ with 1 015.65 fruit and treatment Ⅰ with 834.96 fruit.The branch and bud numbers and the proportions of long,medium and short shoots (0.35∶0.14∶ 1) were suitable for producing high-class fruit in treatment Ⅱ.Different fruit load treatments differed in distribution of light intensity.Treatment Ⅱ was good in light conditions with the best exposure area that received 35％ to 75％ of full sun reached at least 60％ of the canopy area.The trees thus had a high potential to produce a high crop with good quality and a reasonable load.Fruit load had an effect on the color parameters of fruit.The fruit color reflected by parameters in both the canopy periphery (1.0-2.5 m) and the canopy center in treatment Ⅱ was better than the other treatments.Comparison of fruit quality between fruit loads in different canopy positions showed that treatment Ⅱ with a medium fruit load had the best fruit quality in canopy periphery (1.0-2.5 m) and middle periphery,where average fruit weight was 328.75 gram,fruit firmness 8.65,soluble solid content 12.99％,and acid content 0.330％ with a nice looking in treatment Ⅱ.[Conclusion] A medium fruit load (106.63 kg per plant) in treatment Ⅱ had the advantages of even fruit distribution in canopy,high percentage of superior quality fruit,and high and stable yield.Fruit quality of the apples had a close relationship with fruit load in the canopy,which directly influenced the size,soluble solids,sugar acid ratio,VC and surface color of the fruit and the dry matter production in the trees.Meanwhile,medium fruit load overcame biennial bearing.
Keywords：AppleCapacityLightQuality
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 1408-1414 )