Abstract

Root system architecture (RSA) is defined by structural features such as number and length of roots of different orders, distribution area, density, among others. These traits or phenes exhibit a phenotypic plasticity that can respond to environmental stresses. As an initial step in the phenotyping of roots in Prunus species, the RSA of six rootstock genotypes was evaluated. The 1-year-old seedlings were planted in rhizoboxes (60x40x3 cm) in a peat:perlite mixture (2:1) supplemented with controlled release fertilizer and regularly watered every third day until the end of the assay (48 days after planting (DAP). The images of the radical systems were acquired on five dates. Captures were processed with Root Image Analysis-J (RIA-J) software (1). This analysis revealed that it is possible to differentiate the root systems of Prunus spp. based on phenes mainly associated with the distribution of roots, where ‘Rootpac 20’ (R20) showed the widest root system. Likewise, this hybrid rootstock showed to have the longest root length, which, added to the above, gave it the largest convex hull area but the lowest exploration ratio due to its lower root density. Furthermore, it was possible to demonstrate the growth dynamics over time by identifying ‘Mariana 2624’ (M2624) as the rootstock with the highest speed of root generation per unit of time. Finally, these results demonstrate the applicability of this root phenotyping method to fruit tree species in early development stages, which will allow studying the phenotypic plasticity of their root systems in the face of environmental stress conditions.