TY - JOUR

T1 - Genetic variation in dieback resistance in Fraxinus excelsior confirmed by progeny inoculation assay

AU - Lobo, Albin

AU - McKinney, Lea Vig

AU - Hansen, Jon Kehlet

AU - Kjær, Erik Dahl

AU - Nielsen, Lene Rostgaard

PY - 2015

Y1 - 2015

N2 - Ash dieback caused by the pathogenic fungus Hymenoscyphus fraxineus [previously known as H. pseudoalbidus (sexual stage) and Chalara fraxinea (asexual stage)] is a widespread problem in Europe. Here, we assess crown damage from natural infection and necrosis development following artificial controlled inoculations on full-sib and half-sib progeny from Danish Fraxinus excelsior clones with contrasting and well-characterized levels of susceptibility to the disease. The inoculation assay was performed on a total of 123 offspring, and necrosis development monitored over two years. The offspring from low susceptible mother clones developed smaller necroses when compared to offspring from susceptible clones. Their crown damage due to natural infections was also significantly less. The correlation coefficient between average crown damages of mother clones and the average of their progeny was 0.85 (natural infections), while the correlation between crown damage of mother clones and the average necrosis development in their progeny after controlled inoculation was 0.73. The correlation between resistance of parent trees and crown damage/necrosis development on their offspring confirms the presence of heritable resistance and indicates that a bioassay based on controlled inoculations has the potential of becoming a fast and cost-effective tool for estimation of dieback susceptibility in breeding programmes for resistance in ash trees.

AB - Ash dieback caused by the pathogenic fungus Hymenoscyphus fraxineus [previously known as H. pseudoalbidus (sexual stage) and Chalara fraxinea (asexual stage)] is a widespread problem in Europe. Here, we assess crown damage from natural infection and necrosis development following artificial controlled inoculations on full-sib and half-sib progeny from Danish Fraxinus excelsior clones with contrasting and well-characterized levels of susceptibility to the disease. The inoculation assay was performed on a total of 123 offspring, and necrosis development monitored over two years. The offspring from low susceptible mother clones developed smaller necroses when compared to offspring from susceptible clones. Their crown damage due to natural infections was also significantly less. The correlation coefficient between average crown damages of mother clones and the average of their progeny was 0.85 (natural infections), while the correlation between crown damage of mother clones and the average necrosis development in their progeny after controlled inoculation was 0.73. The correlation between resistance of parent trees and crown damage/necrosis development on their offspring confirms the presence of heritable resistance and indicates that a bioassay based on controlled inoculations has the potential of becoming a fast and cost-effective tool for estimation of dieback susceptibility in breeding programmes for resistance in ash trees.

U2 - 10.1111/efp.12179

DO - 10.1111/efp.12179

M3 - Journal article

VL - 45

SP - 379

EP - 387

JO - Forest Pathology (Print)

JF - Forest Pathology (Print)

SN - 1437-4781

IS - 5

ER -