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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #384199
Research Project: Healthy, Sustainable Pecan Nut Production

Location: Fruit and Tree Nut Research

Title: Effect of number of microsatellite markers on estimates of population genetic diversity and structure in the pecan scab pathogen, Venturia effusa

Author
item Bock, Clive
item CHARLTON, NIKKI - Noble Research Institute
item SHILLER, JASON - Noble Research Institute
item RANDALL, JENNIFER - New Mexico State University
item YOUNG, CAROLYN - Noble Research Institute

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/25/2021
Publication Date: 10/1/2021
Citation: Bock, C.H., Charlton, N.D., Shiller, J., Randall, J.J., Young, C.A. 2021. Effect of number of microsatellite markers on estimates of population genetic diversity and structure in the pecan scab pathogen, Venturia effusa. Phytopathology. Vol 11.S2.69.

Interpretive Summary:

Technical Abstract: Scab (caused by Venturia effusa) is the major biotic cause of pecan yield loss in the southeastern US. The pathogen population has been characterized as genetically diverse with limited differentiation, with mating types in equilibrium indicating regular recombination (the sexual stage has been identified in vitro). We compared the ability of 30, 15 and 7 previously developed microsatellites to characterize the population genetic diversity and structure of V. effusa in 11 pecan orchards (n = 784 isolates). Markers were from 7 of 20 chromosomes. Genotype accumulation curves were prepared. There were slight reductions in the number of multilocus genotypes (MLGs) identified using 7 (691 MLGs) or 15 (721 MLGs) compared to 30 (739 MLGs) markers, but the impact was small and the effect on measures of genotypic and gene diversity was negligible (Hexp = 0.793, 0.803 and 0.793, respectively). Based on clone corrected data, linkage disequilibrium was observed in 10 populations using 30 or 15 markers, but in only 5 populations when using 7 markers. Population structure as determined by analysis of molecular variance, minimum spanning networks and discriminant analysis by principal components resulted in similar conclusions (differences were slight). Knowledge of population genetics of V. effusa are urgently needed to understand pathogen population interactions and gene flow, knowledge which will help underpin future breeding efforts to develop durable resistance in this long-lived orchard tree. Using fewer markers will conserve resources while maintaining integrity of results.