A greenhouse bioassay was performed using vitroplants of peach rootstock GF677. They were transplanted to soil samples collected from five replant orchards and five horticultural crops (winter-spring crops) close to the orchards. Plants were grown in greenhouse; root endophytic fungal communities were assessed.
GF677 plants showed a growth reduction significantly higher on horticultural soils than on peach soil. Infection frequency of endophytic fungi did not differ, however, according with analysis of similarity test, community composition widely differed among peach and horticultural sites. Saprophytic fungi prevailed in peach orchards, while Cylindrocarpon destructans and Thielaviopsis basicola were the most abundant species in horticultural soil. These soil borne fungi resulted highly aggressive on peach rootstock after further pathogenicity tests.
The results of this study suggest that peach rootstock can be attacked by the typical soil borne pathogens of horticultural crops. Replanted peach orchards in this study did not seem affected by biotic components of replant. In case of replant of new fruit tree orchards in intensively cultivated areas with continuous crops, greenhouse bioassay with target crop and evaluation of root endophyte fungal communities may help in deciding the best soil use.