L-PEACH: A Computer-based Model to Understand How Peach Trees Grow

Abstract

<jats:p>L-PEACH is a computer-based model that simulates the growth of peach [<jats:italic>Prunus persica</jats:italic> (L.) Batsch] trees. The model integrates important concepts related to carbon assimilation, distribution, and use in peach trees. It also includes modeling of the responses to horticultural practices such as tree pruning and fruit thinning. While running L-PEACH, three-dimensional (3D) depictions of simulated growing trees can be displayed on the computer screen and the user can easily interact with the model. Quantitative data generated during a simulation can be saved to a file or printed for visualization and analysis. L-PEACH is a powerful tool for understanding how peach trees function in the field environment, and it can be used as an innovative method for dissemination of knowledge related with carbohydrate assimilation and partitioning. In this study, we describe the version of L-PEACH that runs on a daily time-step (L-PEACH-d) and how users can run the model and interact with it. To demonstrate how L-PEACH-d works, different pruning and fruit thinning strategies were analyzed. Regarding pruning, model outputs showed 3D depictions of unpruned trees and pruned trees trained to a perpendicular V system. For the fruit thinning studies, we simulated different intensities and dates of fruit thinning in mature peach trees. Total simulated yield increased with crop load but the opposite was observed for average fruit weight. An optimal balance between simulated total yield and average fruit weight was obtained by leaving 150 fruit per tree. Simulating different dates of fruit thinning indicated that fruit weight at harvest was higher on earlier compared with later-thinned trees. The model indicates that fruit thinning should be therefore carried out early in the season to maximize fruit size. The simulation results demonstrate that L-PEACH-d can be used as an educational tool and facilitate the adoption of suitable cultural practices for efficient production.</jats:p>

IMapple: a source-sink developmental model for ‘Golden Delicious’ apple trees

“…We have developed a 3D simulation framework inspired by L-peach (Lopez et al, 2010) and MAppleT (Costes et al, 2008) that use the analogy of an electrical circuit. While our framework described here is applied to Golden Delicious apples, it has the flexibility to enable it to be adapted to simulate the growth of other tree species.…”

“…The underlying simulation system used L-systems for the tree generation and hidden semi-Markov chains for randomization of tree topology and geometry. Similarly, a growth simulation of peach trees, called L-PEACH, was described by Lopez et al (2010). Their model is largely based on carbon assimilation, distribution, and utilization.…”

“…Resources may include water, carbohydrates, or nutrition and it is up to the user to define. The resource transport system is motivated by the research of (Lopez et al, 2010) who simulated the flow of carbohydrates in a tree using the analogy of an electrical circuit. This is possible due to analogies between hydraulic and electric current flow as shown in Table 1.…”

“…All currents in a normalized circuit are solved by the technique of folding and unfolding described by Lopez et al (2010). Currents are computed iteratively because electrical components may be non-linear ̶ their voltage/resistance may depend on the current or potential.…”

“…This conversion is not linear and it depends on several factors. We use relationships described by (Lopez et al, 2010). A leaf has charge capacity proportional to its size.…”