Evaluation Of Light Interception Of Apple Tree Canopy Based On3-Dimensional Model

Traditional tree canopy evaluation of light interception is not comprehensive enough,lack of quantitative indicators to evaluate the ability of bearing in continuous years and lackof analysis of cultivars effect on canopy. So experiments were carried out with two cultivarsof apple(Red Fuji&Gala) subjected to two canopy shapes(TS: Tall Spindle Canopy; FS: FreeSpindle Canopy): Reconstruction of3-Dimentional apple tree canopy model; Based on3Dmodel, whether the STAR value can represent the light intercepton efficiency was analyzedand the architecture and light interception efficiency of treatments were studied; Bud onannual shoot of2010and latent bud were marked, rate of germinating and flowering werecaculated and camparision of cultivars and canopies were studied; Relationship betweenSTAR and fruit quliality or bud differentiated were analyzed. The reasults are as follows:13D model construction and accuracy evaluationThe proposed method which combined3D digitizing and reconstruction simulation wasan accurate way to build the3D apple tree canopy model, thus quantify geometricalcharacteristics of canopy, reflect the canopy components and architecture and gain the3Ddata of the canopy. The3D canopy model was stable and can be used to evalute the canopystructure.2Characters of architecture and light interception of two cultivas of apple subjected totwo canopy shapesTShad a greater balance between vegetative and bourse shoot growth than FS. STARvalue could be used as a parameter to represant the ability of effective leaf aera thatintercepted light, canopy potential relative lighe intensity and leaf area index of canopy.Theappropriate LAI and STAR can be gained from the regression equation between STAR andLAI or RLD. The TS tree campared to FS tree: STAR of whole canopy increased by14%,bourse shoot increased by53%; vegetative shoot increased by20%; The change of STARvalue during one day for the TS canopy were bimodal curve with two peaks, while FS canopychanged as a single peak curve; The STAR value of Gala were greater than Fuji during oneday; The TS canopy STAR value were greater than FS canopy with the same cutivar.STAR value increased as tree height increased, the trends were similar between thedifferent treaments: from0to60cm, STAR value decreased,60~160cm STAR increasedslowly, with the height over160cm the STAR value increased rapidly until to the maximum at the top of the canopy; when the height under160cm, the STAR value of tall spindle Galagreater than Fuji, TS canopy had greater STAR value than FS canopy with the same cultivar;as height over180cm, between cultivars STAR of Gala were higher than Fuji.3Yield and quality of apple of two cultivas of apple subjected to two canopy shapesParameters of fruit quality of soluble solids, coloured area ratio, diameter and longitudinal diameter of TS tree were highter than FS canopy tree; especially for TS Fujitree, except titratable acid and firmness the other parameters were highter than othertreatments.The yield of Fuji higher than the Gala; with the same cultivar, the TS had better yield perplant, single fruit weight, yield per leaf area, yield per volume than the FS canopy; comparedto the FS canopy tree, the TS tree have higher canopy space and foliage utilization, tallspindle tree production efficiency were more highter and fruit diameter were much biggerthan FS canopy tree.4Effect of canopy shapes and cultivars on apple bud differentiationThe ratio of differentiated teriminal bud and lateral as flower in TS were significantlyhigher than FS, and TS have more bud had not differentiated. Gala with lower ratio ofdifferentiated teriminal bud and lateral to flower than Fuji. Tree canopy have no significantlyeffect on β and ψ, between cultivar β of Fuji was higher and ψ was lower than Gala;Especially for Fuji with TS significantly improved the ability of differentiated bud to flowerand the value of β and ψ, while with highest ratio of latent bud than other tretments at thesame time; The ratio of latent bud differentiated to all was0.15to0.26in tretments, TS withlower ratio of latent bud differentiated while have higher ratio of differentiated latent bud toflower than FS. Cultivars rsflected differently to canopy shapes. Higher light interceptionimproved the ability of terminal and latent bud to differentiate and flower.