Vegetative and Reproductive Behavior of 'Conference' and 'Williams' Pear Trees Trained to V-Shape System

Abstract

V-shape systems represent an efficient and popular option to increase yields and fruit quality. Here we present a detailed study on canopy and root system growth and conformation, yields, fruit quality and dry matter partitioning of 'Conference' (C) and 'Williams' (W) pear trees trained to V-shape system. Digital images were used to determine total stem and root length, mean diameter and surface area; canopy and root system spread area, shape index and volume, canopy height and root depth. Dry weights were used to calculate dry matter partitioning. Stems of W trees were longer and thinner than those of C, which resulted in similar stem dry weights for the two cultivars, whereas root dry weight of W was greater than C due to greater diameter. W canopies were also taller, wider, and occupied a larger volume than C canopies, but similar for length density (length/volume) and roundness of spread area. C root systems were shallower, wider, and similar to W root systems for volume, length density and roundness of spread area. W trees also had larger leaf area and leaf/root surface ratio than C trees. W trees produced higher yields than C trees, but exhibited the same fruit weight per unit leaf area. C fruit flesh was firmer than W fruit flesh, suggesting a different degree of ripeness between the two cultivars. Despite adjustment for the degree of ripeness, W fruit was bigger, but less sweet and more acidic than C fruit. C trees partitioned a greater proportion of dry matter to stems, a similar proportion to roots, and a smaller proportion to leaves and fruit than W trees. In the early stages of orchard life, W trees represent a generally more efficient option for pear cultivation using V-shape systems.