Abstract:

【Objective】The objective of the study is to analyze the genetic diversity and find the preponderant populations of Botryosphaeria berengeriana isolates, the causal agents of ring rot disease of apple.【Method】Sixty-four isolates were identified by their morphologic characteristics in culture and their pathogenicity tests. Isolates were identified by their ITS rDNA sequence. Inter-simple sequence repeat (ISSR) analysis was used to investigate the genetic diversity of its isolates.【Result】Sixty-four isolates were identified as B. berengeriana by morphologic characteristics in culture and pathogenicity tests. The data of the ITS rDNA from selected 17 isolates accord with data of B. berengerian and separated into two haplotypes H1 and H2. The 13 functional ISSR primers generated 88 polymorphic bands within a total of 121 bands and revealed 72% polymorphism and could differentiate all 64 isolates. Their genetic similarities were from 0.44 to 0.99. Two groups of 64 isolates were identified based on their ISSR. Group 1 contains 21 isolates, while group 2 consists of 43 isolates.【Conclusion】In this study, it was found that the genetic diversity of B. berengeriana isolates were not correlated to their regions , symptoms and tissues of trees. Sixty-four isolates were separated into two ISSR groups, and group 2 predominated over group 1 in orchards .

Key words: apple ring rot, Botryosphaeria berengeriana, ISSR, genetic diversity