Effects of reductive soil disinfestation during low-temperature stubble free period on the control of watermelon Fusarium wilt

Abstract

In order to clarify the controlling effect of reductive soil disinfestation (RSD) during low-temperature stubble idle period on watermelon Fusarium wilt, we conducted a pot experiment, containing control (CK), flooded control (FCK), and RSD treatments incorporated with 2% (w/w) alfalfa meal (AL), 0.25% acetic acid (AC), and AL+AC. Real time PCR and Illumian Miseq sequencing were used to determine the abundances of fungi and Fusarium oxysporum as well as fungal community composition. The disease incidence and yield of watermelon were measured. Results showed that the abundance of Fusarium oxysporum and the ratio of Fusarium oxysporum to fungi significantly decreased in the FCK and three RSD treatments, and the disinfestation effects of these treatments ranged from 86.1% to 94.6%. The yield and disease incidence of watermelon significantly increased and decreased in all of the RSD treatments, respectively. There was no significant diffe-rence between FCK and CK treatments. The control efficiencies of Fusarium wilt in AL, AC, and AL+AC were 63.2%, 73.7%, and 94.7%, respectively. The compositions of fungal community in the AL and AC treatments were significantly changed, whereas FCK did not affect fungal community. The relative abundances of dominant fungal genera, such as Zopfiella, Pseudeurotium, Geotrichum, Ascobolus, Westerdykella, and Guehomyces, increased in the RSD treatments. Most of those genera were significantly and negatively correlated with the abundance of Fusarium oxysporum, the ratio of Fusarium oxysporum to fungi, and the disease incidence. In conclusion, RSD treated in the low-temperature stubble free period could effectively control watermelon Fusarium wilt by reshaping fungal community composition.