Grapevine adventitious root traits vary based on propagation method

Development of new rootstocks is an effective strategy to continue grape production despite increased abiotic stress in a changing climate. We measured an F1 population derived from a cross between a drought resistant (110R) and drought susceptible (101-14 MGT) rootstock to identify quantitative trait loci (QTL) for root system architecture traits. We also compared traits and QTL between two propagation methods: hardwood and herbaceous cuttings. Plants were grown for 35 days and measured by destructive harvest and imaging, which provided 17 traits related to root system architecture. We identified two significant QTL for root system architecture traits for root thickness and root angle. Generally, hardwood cuttings had significantly larger root systems, thicker roots, and a higher ratio of lateral roots to adventitious roots, however genotypes did not have consistent phenotypes across propagation methods. This finding indicates that the interpretation of experimental results should depend on the propagation method used. We also found complex, multigenic control of root system architecture traits, which supports the use of genomic selection models for breeding. We expect these results to guide future research using young grapevine root systems and provide insight into the genetic control of root architecture in grapevine.