S16 - Session P2 - Effect of floral differentiation on shoot morphology and consequences on canopy light interception based on 3D virtual plants

Authors: Xiaoyun Zhang, Kai wang, Xiuling Li, Weiwei Yang *

Floral differentiation modifies shoot morphology and the canopy performance in apple. This study aimed at comparing shoot morphology among shoot types and sensitivities of relative fractions among shoot types on canopy light interception and photosynthetic capacities in 'Fuji' and 'Gala' apple cultivars. Shoots were distinguished according to length (long and short) and type (bourse, bourse shoot and vegetative shoot). Canopies were digitized at annual shoot scale. At least 60 annual shoots were digitized at both shoot and leaf scale for each shoot type and cultivar. Three-dimensional (3D) virtual isolated shoots range from 0.5 to 40 cm with same axis angle for each shoot type and cultivar and 3D canopies for each cultivar were reconstructed based on allometric relationships and leaf angle distributions. Light interception efficiency was estimated for all isolated virtual shoots. The sensitivity of relative fraction between bourse shoots and vegetative shoots on canopy light interception and photosynthetic capacities were investigated by in silico experiments. The VegeSTAR software was used to estimate light interception efficiency. Significant differences were detected among shoot types rather than between cultivars for shoot number and leaf area. The mean internode length of bourse shoots (BS) was significantly higher than vegetative shoots (VS), and VS have more horizontal orientation of leaves than bourse shoots (BS), irrespective of shoot length. Then, the light interception efficiency of BS was significantly greater than VL, irrespective of shoot length. The in silico experiments showed that increase in the fraction of BS increased the canopy light interception efficiency for both cultivars. The virtual plant will be helpful to optimize shoot composition within canopy, thus achieving a canopy with efficient light interception.