Abstract:Mold rot is one of the main factors which lead to the postharvest loss and short shelf-life of blueberry fruits. The objective of this study is to determine the primary fungal pathogens which may cause postharvest decay of blueberry during storage process, and to investigate the biological characteristics of pathogens, providing theoretical basis for disease control and further research. The typical postharvest decay sympotoms of blueberry were described. Five strains designated as LMA, LMB, LMC1, LMC2 and LMC3 were respectively isolated from diseased blueberry fruit harvested in Anji County of Zhejiang Province. Isolates were characterized by colony morphology and conidial characteristics at 28℃ in dark. The internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1/ITS4) from five isolates was amplified and sequenced. The consensus ITS sequences of five isolates were compared with the associated sequences in GenBank. MEGA 5.0 was used to draw the phylogenetic tree of five isolates and other related sequences. The isolated strains were identified as B. cinerea, T. viridescens, P. cecidicola, P. polonicum and P. expansum, respectively, according to the morphologies of colony and conidial and the rDNA-ITS sequence analysis. The biological characteristics of the isolated strains were further investigated including the effects of different medias, carbon and nitrogen sources, temperatures, pH values and light on mycelial growth of five fungal pathogens using cross method, and the results showed that the suitable culture media and temperature for the five strains were blueberry extract-glucose media and 25~30℃, respectively. The optimal carbon source was fructose for LMA, LMC1 and LMC2 strains, sucrose for LMB strain, and soluble starch for LMC3 strain. The optimal nitrogen source was peptone for LMA, LMC1 and LMC2 strains, yeast extract powder for LMB1 and LMC3 strains. The effects of light on the mycelia growth of LMA, LMC1 and LMC2 were significant, but that was insignificant on the growth of LMB and LMC3 strains.
