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Genetic population structure and fungicide resistance of Botrytis cinerea in pear orchards in the Western Cape of South Africa
Author(s) -
Wessels B. A.,
Linde C. C.,
Fourie P. H.,
Mostert L.
Publication year - 2016
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12523
Subject(s) - biology , botrytis cinerea , orchard , pear , fungicide , population , benomyl , microsatellite , botany , horticulture , genetic diversity , gene flow , genetic variation , allele , genetics , gene , demography , sociology
Botrytis cinerea isolates from pear blossoms ( Pyrus communis ) in South Africa were collected from four orchards in two production areas in the Western Cape. The cryptic species status based on vegetative‐incompatibility alleles of the Bc‐ hch gene indicated that all the isolates belonged to B. cinerea . A microsatellite analysis of B. cinerea populations was performed to assess the genetic population structure. Total gene diversity ( H ) was high, with a mean of 0.69 across all populations. Some genotype flow was evident between orchards as indicated by the spread of microsatellite multilocus genotypes, in agreement with the moderate, but significant population differentiation among orchards (mean φ PT = 0.118, P = 0.001). Index of association analyses ( I A and r̅ d ) suggest that the populations reproduce mostly asexually, even though mating type distribution did not differ significantly from a 1:1 ratio, suggesting frequency‐dependent selection. Isolates resistant to benomyl were evident in one orchard only. This orchard was also significantly differentiated from all other populations, suggesting infrequent localized selection for benomyl resistance. Overall, the findings of this study highlight the dangers of a mixed reproduction system, and stress the importance of regularly monitoring fungicide resistance levels towards developing more efficient management practices.