MORPHOLOGICAL AND MOLECULAR CHARACTERIZATION OF COLLETOTRICHUM SPP FROM CITRUS ORCHARDS AFFECTED BY POSTBLOOM FRUIT DROP IN BRAZIL

Brazilian isolates of Colletotrichum spp. from citrus orchards affecte d by postbloom fruit drop were examined for colony colour, mycelial gr owth, benomyl-resistance, pathogenicity, and genetic variability by ra ndom amplified polymorphic DNA (RAPD) analysis. All isolates were obta ined from flowers and persistent calyxes from different citrus hosts f rom Sao Paulo, Brazil. DNA polymorphisms detected after amplification with random 10-mer primers were used to classify the isolates into two groups. Group I isolates grew rapidly on potato-dextrose agar (PDA) a nd were sensitive to benomyl, and group II isolates grew slowly on PDA and were benomyl-resistant. Colletotrichum acutatum was analyzed by R APD and had high genetic similarity with group II isolates of Colletot richum from citrus. Probably, the group I is C, gloeosporioides and gr oup II is C. acutatum.