A Stochastic Model to Describe the Fruit Number and Position on Long Peach (Prunus Persicae) Shoot

A stochastic model of fruit number and position on a long peach (Prunus persica cv. yingzhui) shoot of 10- year-old tree is presented. In model there are generally 3 states in which state 2 represents that a node with two fruits, state 1 represents that a node with one fruit, state 0 represents that a node without fruit. Parameters of model are estimated using the STAT module of Matlab software. The observed data are sampled from mature trees at two harvest seasons during two years in a row (2013-2014) in Lianping, Guangdong, China. Results indicate that upper nodes usually have one fruit, middle nodes have no more than one to two fruits, and most of basal nodes have zero to one fruit. The total number of fruits increases with the number of remaining nodes after pruning. Occupancy distributions of different states in model demonstrate that pruned long shoots had 5 to 7 fruits, whereas unpruned long shoots averaged more than 10 fruits. The fruit distributions on the shoots follow a well-defined pattern: nodes that bear one or two fruits were significantly higher in the median part of the shoot but lower on the basal and distal nodes. In addition, three- dimensional representations of the fruit position were reconstructed using PruningSim software.