Integration of tree source and sink activities.

Tree crop modeling could be instrumental in facilitating integration of numerous aspects of the development, growth and physiology of fruit tree crops and provide a valuable tool for testing concepts for understanding how fruit trees work, if it could be achieved. This chapter presents a synopsis of how modeling of fruit trees was approached. It focuses on the development of a mechanistic, compartmental model of mature peach tree carbon partitioning over a growing season. The model was termed a compartmental model because carbohydrates were only distributed to the collective compartments of fruits, leaves, stems and large branches, and the trunk according to their relative demand functions as the season progressed. Roots were only given carbohydrates when the demands of all of the other organs were fulfilled. This model demonstrated that carbohydrate partitioning in trees could be modeled without deterministic, empirically derived, partitioning coefficients and was useful for indicating periods of the growing season when calculated photosynthetic assimilation was not adequate to supply calculated carbohydrate demands of growing organs. The development of the described model is so complex that the modeling work will never be fully completed. However, to demonstrate the utility of this modeling approach, it was decided to develop an L-Almond model using the same approach.

Subjects develop tolerance to Pru p 3 but respiratory allergy to Pru p 9: A large study group from a peach exposed population

Peach tree allergens are present in fruit, pollen, branches, and leaves, and can induce systemic, respiratory, cutaneous, and gastrointestinal symptoms. We studied the capacity of peach fruit/Pru p 1, Pru p 3, Pru p 4, Pru p 7 and peach pollen/Pru p 9 for inducing symptoms following oral or respiratory exposure in a large group of subjects. We included 716 adults (aged 21 to 83 y.o.) exposed to peach tree pollen and fruit intake in the study population. Participants completed a questionnaire and were skin tested with a panel of inhalant and food allergens, including peach tree pollen, Pru p 9 and peach fruit skin extract. Immunoglobulin E antibodies (SIgE) to Pru p 1, Pru p 3, Pru p 4 and Pru p 7 were quantified. Sensitised subjects underwent oral food challenge with peach fruit and nasal provocation test with peach tree pollen and Pru p 9. The prevalence of sensitisation to peach fruit was 5% and most of these had SIgE to Pru p 3, with a very low proportion to Pru p 4 SIgE and no SIgE to Pru p 1 and Pru p 7. In only 1.8%, anaphylaxis was the clinical entity induced. Cases with positive skin tests to peach and SIgE to Pru p 3 presented a good tolerance after oral challenge with peach fruit. The prevalence of skin sensitisation to peach tree pollen was 22%, with almost half recognising Pru p 9. This induced respiratory symptoms in those evaluated by nasal provocation. In a large population group exposed to peach fruit and peach tree pollen, most individuals were tolerant, even in those with SIgE to Pru p 3. A positive response to Pru p 9 was associated with respiratory allergy.

A Practical Guide for Peach Irrigation Scheduling in Florida

The goal of this publication is to provide a practical guideline for irrigation of young (1–3 years old) and adult (>3 years old) peach trees cultivated in Florida. This document is based on field research of peach water uptake conducted by UF/IFAS. The first section describes peach tree growth stages and their respective crop water demand in central Florida. The second and third sections present practical information on preparing year-round irrigation scheduling for young and adult peach trees, respectively. More information about irrigation practices for peaches is provided in EDIS publication HS1316 (https://edis.ifas.ufl.edu/hs1316).

The effect of the short pruning on the yield and quality of the fruits at the peach tree

The aim of our research was to determine the effect of short pruning on the productive and vegetative characteristics of peach trees. The research was conducted on two cultivars, ‘Redhaven’ and ‘Fayette’. Three short pruning treatments were applied, with heading of the bearing branches at 20, 30, and 40 cm in length and a control, without heading. The following characteristics were evaluated: the growth of the TCSA, the number of thinned fruitlets, the number of fruit and yield per tree, the average weight of the fruits and the diameter of the fruits. Based on our research, we made several observations: the pruning method did not affect the growth of the TCSA; the number of thinned fruitlets decreased with a reduction in the length of the bearing branches; the number of fruits and yield per tree decreased with a reduction in the length of the bearing branches. A higher average fruit weight and percentage of fruits with a bigger diameter were calculated from the trees with the short pruning, but with a different share depending on the cultivar.