YIELD PERFORMANCE ASSAY AND FRUIT QUALITY OF STRAWBERRY GENOTYPES TOLERANT AND SUSCEPTIBLE TO FUSARIUM OXYSPORUM AND TO A VIRAL COMPLEX

Root and crown rot produced by Fusarium oxysporum and by a viral complex consisting of at least five viruses has been affecting the region of Irapuato, Guanajuato, Mexico, causing serious damage to the strawberry production. For this reason, 14 years ago two Mexican organizations, INIFAP (the National Institute for Forestry, Agriculture, and Livestock Research) and CINVESTAV (the Centre for Research and Advanced Studies, of the National Polytechnic Institute) started a breeding program to produce cultivars tolerant to both kinds of pathogens, using Fragaria chiloensis, from the central coast of California, USA, as source of resistance. During the season 2010-2011 a group of five clones, (07.4, 07.35, 07.61, 07.89 and 07.90), carrying 12.5% of F. chiloensis genetic information, were evaluated on untreated soil planted with tray plants under macrotunel, vs. a group of nine clones of Fragaria x ananassa, and the cultivar 'Camino Real', which was used as a control, to estimate the progress in the genetic program for characteristics such as productivity and fruit quality in this group of clones. Clone 07.35 exhibited the highest early production and total yield, namely 20.1 and 69.2 t.ha-1 respectively, outperforming all other cultivars, including 'Nikte' and 'Camino Real', although these two had higher fruit weight and firmness. During the assay, the presence of virus was evaluated through monitoring by means of UC-4 virus indicator plants. Most of the clones carrying F. chiloensis genes tested, were more tolerant to the viral complex than cultivars of F. x ananassa, and at least two of the clones tested (07.4 and 07.35), exhibit tolerance to both pathogens, and have the potential to outperform those of commercial cultivars. Nine of the 14 genotypes were susceptible to one or both pathogens.