Root Dynamics of Peach Replant Tolerant and Susceptible Rootstocks in Soilswith Different Cropping History

Replant disease (RD) is a major constraint for the establishment of economically viable tree fruit production systems. The use of tolerant rootstocks is considered the most cost-effective and long-term sustainable option to manage RD. The present study examines root production and lifespan of a replant tolerant and susceptible peach rootstock in a replant and non-replant soil. RD susceptible rootstock genotype Lovell and RD tolerant rootstock genotype Viking were established in a replant and non-replant site. Aboveground growth was determined by measuring the tree-trunk cross sectional area annually, and belowground root dynamics were tracked during a 2-year period using minirhizotron technology. Viking trees were significantly larger than Lovell in the replant site only. No significant differences were observed on the number of new roots produced by the two rootstocks in the replant or non-replant sites. In the replant site, roots of Viking remained white for a longer period of time, had higher AMF colonization, and second order roots had longer lifespans than those of Lovell rootstock; however no differences were observed between rootstocks in the non-replant site. Future research on identification of host defense mechanisms is needed for the development of tools that will support and accelerate breeding of resistant rootstocks.