<abstract xmlns="http://www.w3.org/1999/xhtml">We investigated the association of inbreeding and infection by the introduced disease white pine blister rust (caused by the fungus <italic>Cronartium ribicola</italic> J. C. Fisch) with genetic diversity of whitebark pine (<italic>Pinus albicaulis</italic> Engelm.) by genetically comparing cohorts of different ages in natural stands. Isozyme analysis of bud tissue was used to estimate expected and observed heterozygosity (He and Ho), and Wright’s fixation index (Fis) for three age cohorts (seedling, young, and mature), sampled from 14 sites in British Columbia, Oregon, Idaho, and Montana. Comparison of genetic diversity parameters among cohorts within a site was used to assess the extent and persistence of inbreeding with age, while comparisons of parameters among sites within a cohort were used to assess the impact of the disease on genetic diversity. Significant evidence of inbreeding (Fis >0) was found in all age cohorts. When sites were stratified by level of blister rust infection, differences in Fis and Ho among cohorts were only significant when level of infection was low. A significant negative association was found between level of blister rust infection and Ho in the mature cohort. This suggests that when differential selection due to blister rust is weak, more heterozygous individuals may be favored; however, more homozygous individuals may have higher fitness under higher blister rust levels</abstract>

We investigated the association of inbreeding and infection by the introduced disease white pine blister rust (caused by the fungus Cronartium ribicola J. C. Fisch) with genetic diversity of whitebark pine (Pinus albicaulis Engelm.) by genetically comparing cohorts of different ages in natural stands. Isozyme analysis of bud tissue was used to estimate expected and observed heterozygosity (He and Ho), and Wright’s fixation index (Fis) for three age cohorts (seedling, young, and mature), sampled from 14 sites in British Columbia, Oregon, Idaho, and Montana. Comparison of genetic diversity parameters among cohorts within a site was used to assess the extent and persistence of inbreeding with age, while comparisons of parameters among sites within a cohort were used to assess the impact of the disease on genetic diversity. Significant evidence of inbreeding (Fis >0) was found in all age cohorts. When sites were stratified by level of blister rust infection, differences in Fis and Ho among cohorts were only significant when level of infection was low. A significant negative association was found between level of blister rust infection and Ho in the mature cohort. This suggests that when differential selection due to blister rust is weak, more heterozygous individuals may be favored; however, more homozygous individuals may have higher fitness under higher blister rust levels

Changes in Genetic Diversity of Whitebark Pine (<italic>Pinus albicaulis</italic> Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

Centre for Forest Conservation Genetics, Department of Forest Sciences

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Changes in Genetic Diversity of Whitebark Pine ( Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

We investigated the association of inbreeding and infection by the introduced disease white pine blister rust (caused by the fungus Cronartium ribicola J. C....

Changes in Genetic Diversity of Whitebark Pine (Pinus albicaulis Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

Published Online: Aug 05, 2017

Page range: 113 - 123

Received: Apr 09, 2010

DOI: https://doi.org/10.1515/sg-2011-0016

Keywords
whitebark pine, white pine blister rust, genetic diversity, isozymes, inbreeding, cohort analysis, heterozygosity

© 2011 A. D. Bower et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Changes in Genetic Diversity of Whitebark Pine (Pinus albicaulis Engelm.) Associated with Inbreeding and White Pine Blister Rust Infection

Published Online: Aug 05, 2017

Page range: 113 - 123

Received: Apr 09, 2010

DOI: https://doi.org/10.1515/sg-2011-0016

Keywordswhitebark pine, white pine blister rust, genetic diversity, isozymes, inbreeding, cohort analysis, heterozygosity

© 2011 A. D. Bower et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
whitebark pine, white pine blister rust, genetic diversity, isozymes, inbreeding, cohort analysis, heterozygosity