GRAPE PHYLLOXERA (Daktulosphaira vitifoliae Fitch) IN ARGENTINA: ECOLOGICAL ASSOCIATIONS TO DIVERSITY, POPULATION STRUCTURE AND REPRODUCTIVE MODE.

WALKER ANDREW; ALONSO RODRIGO; ARANCIBIA CELESTE; BUSCEMA FERNANDO; RIAZ SUMMAIRA; MARTINEZ LILIANA; AGUERO CECILIA; WALKER ANDREW; ALONSO RODRIGO; ARANCIBIA CELESTE; BUSCEMA FERNANDO; RIAZ SUMMAIRA; MARTINEZ LILIANA; AGUERO CECILIA

AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 p. 284 - 291

1322-7130

Background and aims: Grape phylloxera (Daktulosphaira vitifoliae), is a damaging grapevine pest widely distributed which has devastated own rooted V. vinifera vineyards in Europe triggering economic crisis with demographic implications. In Argentina, the pest has not caused a major damage, yet. This work aims characterize Argentinean phylloxera?s genetic diversity; to determine its structure and reproductive mode; to compare Argentinean genotypes with other countries? and to find relationships between infestation levels and genotype profiles with ecological factors. Methods and results: 129 samples were taken from different Argentinean provinces and analysed with 21microsatellite markers. A total of 17 MLGs were identified. UPGMA analysis showed 2 major groups designated as ?Large Cluster? and ?Small Cluster?. With PCoA analysis Peruvian, California biotype A and B and Argentinean samples grouped together showing high dissimilarity with phylloxera from the other countries. No common MLGs between Argentinean and foreign samples were found. The populations is not structured (FST P= 0.305), the occurrence of sexual events is unlikely (highly significant Psex values for all the repeated MLGs). The associations were significant for infestation level-climate region (χ2 = 6.14, d.f. = 2, p = 0.0465) and infestation level-grape colour (χ2 = 9.33, d.f. = 2, p = 0.0094). In both cases, ?Medium? was the significant category (p= 0.002314 and p=0.013997, respectively). The genetic cluster-climate region association was also significant (Irwin Fisher bilateral test value = -0.57, p< 0.0001), cold region associated with ?Small Cluster? and warm region with ?Large Cluster?. Conclusions: Two main groups of phylloxera genotypes were identified in Argentina and both showed some affinity to reference samples of the California biotype B strain. Parthenogenesis is proposed as the main reproductive mode but the occurrence of rare sexual reproduction is not ruled out. No particular structure was observed in phylloxera populations and more variability was observed among the individuals. We also established association of medium infestation with red/pink berried V. vinifera cultivars, and higher infestation with white fruited cultivars.Significance of the study: This is the first detailed report of phylloxera population biology in Argentina that utilizes DNA-based SSR markers and provides the foundation to other studies, tracking and monitoring seasonal changes in the population structure of phylloxera, devising and establishing measures to control movement of different genotypes between regions and identifying additional types. Due to the diversity, there is immediate need to study the biology of feeding behaviour of local genotypes on the rootstocks used in Argentina.