Size-Controlling Cherry Rootstock Selection Based on Root Anatomical Characteristics

Abstract

Over the past few decades, numerous studies investigated the vigor and productivity of fruit species depending on the rootstock on which they were grafted, but the exact size-controlling mechanism itself has not been fully elucidated, nor were the rapid rootstock selection methods defined. Thus, this study aimed to assess the root anatomical characteristics and their influence on the overall ‘Summit’ cherry tree vigor to confirm the size-controlling effect and establish an effective protocol for rapid rootstock selection. Plant material included three cherry species (Prunus cerasus, Prunus fruticosa, and Prunus mahaleb) and interspecific hybrid ‘Gisela 5′ (P. cerasus × Prunus canescens) as a control. The detailed anatomical analysis included root samples with the differentiated secondary structure taken from the sampling depth of 10–15 cm. Roots with percentages of vessels ≈40%, ≈50%, and ≈10% belonging to size-classes ˂700 µm2, 700–2000 μm2, and ˃2000 µm2 (respectively) are presumed to provide optimal amounts of water solution to the scion, without compromising plant vitality, drought tolerance, and size-controlling effect. Statistically significant correlations were determined between anatomical properties (the percentage of vessels, especially ˃2000 µm2, xylem porosity, and hydraulic conductivity, both per mm2 and total root) and vegetative growth in the juvenile vegetative phase, indicating direct vessel size influence on plant vigor and its employment in size-controlling cherry rootstock selection.