A Study on Fruit Setting Model of Parent Branch in Nectarine Tree

Abstract

The fruit setting models of individual parent branch in 10-year-old nectarine tree (Prunus persica var. carminum) with different heading intensities were studied over two successive growth seasons (2016-2017). Parent branches after being headed, which is comprised of a succession of nodes with zero to two flower buds which can produce fruits, is characterized by a Markov chain with three states, and therefore the corresponding model parameters consists of initial probability together with the following transition probabilities of states (fruit setting types): state 2 represents two fruits on bearer node; state 1 represents one fruit on bearer node; state 0 represents no fruit on bearer node. On each node, the numbers of fruits and their spatial arrangement per parent branches follow a definite pattern that remains the same as long as the selective heading intensity is kept constant, i.e. that fruit bearing was significantly higher in the mesotonic zone of the shoot and lower in the basal and apical zone. The simulation results with Markov chain indicate that this final fruit set sequence was correlated with the heading activity. Three-dimensional representations of the fruit setting processes using Pruningsim software illustrate more vividly perhaps than the numbers of fruit occurrence being listed in a table and/or figure. The visual comparison between 3D reconstructions and realistic photographs may generate a natural feedback of the pruning measurements, at the shoot scale.