High genetic variation and moderate to high values for genetic parameters of Picea abies resistance to Pissodes strobi

Abstract

Genetic parameters of Picea abies resistance to the white pine weevil (Pissodes strobi Peck) were estimated from 193 full-sib and 166 half-sib families in six 10-year-old progeny trials. The estimated family and individual heritability values for the cumulative weevil attack rate between ages 6 and 10 (CWA 6-10 ) were high and moderate for both full-sib families (0.61 and 0.28, respectively) and half-sib families (0.85 and 0.40, respectively), indicating strong genetic control for this trait in Norway spruce. The fact that specific combining ability (SCA) variance represents 35 % of the general combining ability (GCA) variance suggests that non-additive (dominant) effects are weak. The strong type B correlations found for CWA 6-10 (b r B ¼ 0:96 for full-sib families and b r B ¼ 0:81 for half-sib families) indicate that family ranks were stable across sites. For three of the five sites with high attack levels, genetic correlations were not significant between CWA 6-10 and tree height at age 5. Moderate positive genetic correlations were detected between CWA 6-10 and tree diameter at age 10 (b r A from 0.29 to 0.60), but specific families showing both high resistance and good diameter growth can be found. These results suggest that the genetic improvement of Norway spruce for resistance to white pine weevil can be achieved successfully without adversely affecting growth.

Genetic variation in resistance of Norway spruce seedlings to damage by the pine weevil Hylobius abietis

“…Previous results on Mediterranean pine trees reveal that this could be the case with resistance to the pine weevil (Zas et al 2005(Zas et al , 2008. Genetic correlations between resistance to P. strobi and growth of Norway spruce were, however, either not significant or positive (Mottet et al 2015). The emergence of these trade-offs seems thus to be context dependent (Sampedro et al 2011).…”

“…The observed variation in resistance to the pine weevil in Norway spruce was significant but lower than for pine species against the pine weevil (Zas et al 2008;Zas et al 2005) and for Norway spruce against other weevil species (Mottet et al 2015). Particularly relevant is the variation in resistance of Norway spruce to the white pine weevil P. strobi, a serious pest native to North America, where it causes important damage to the introduced Norway spruce.…”

“…Plant lineages may also differ in the nutrient content of their tissues ) and even in the volatile compounds they emit (Blanch et al 2012), which may affect the attraction, preference, and damage caused by herbivores. As a consequence, resistance to specific insect pests usually shows large withinpopulation genetic variation (Moreira et al 2013;Mottet et al 2015;Yanchuk et al 2008;Zas et al 2005), and this variation can be exploited in breeding programs for improving tree resistance. Using conventional selection and breeding, for example, has allowed the deployment of Sitka spruce (Picea sitchensis [Bong.]…”

“…Surprisingly, despite the huge effort for improving growth and timber properties that has been done in this species across multiple countries (Jansson et al 2013), to our best knowledge, no single attempt has been done to explore whether resistance of Norway spruce to the pine weevil is genetically variable and can be enhanced by conventional selection and breeding. Results from breeding programs in Eastern Canada has revealed large genetic variation in Norway spruce in resistance traits against another weevil (the white pine weevil P. strobi), with most of this variation being additive (Mottet et al 2015). Despite the lack of information on genetic variation in resistance to the pine weevil for northern conifer species, significant additive variation in resistance has been reported in Mediterranean pines of Southern Europe, such as the native Pinus pinaster Aiton (Zas et al 2005) and the exotic Pinus radiata D. Don (Zas et al 2008).…”

“…Particularly relevant is the variation in resistance of Norway spruce to the white pine weevil P. strobi, a serious pest native to North America, where it causes important damage to the introduced Norway spruce. Evaluation of genetic trials in Eastern Canada has revealed large additive variation in Norway spruce to this insect (Mottet et al 2015). Norway spruce is exotic in Canada and has not co-lived naturally with the white pine weevil, so the observed variation is likely a byproduct of variation in resistance traits to other native pests Significant correlations are highlighted in italicized font.…”