Do Seedlings Derived from Pinewood Nematode-Resistant Pinus thunbergii Parl. Clones Selected in Southwestern Region Perform Well in Northern Regions in Japan? Inferences from Nursery Inoculation Tests

Koji Matsunaga,Atsushi Watanabe,Taro Yamanobe,Mineko Ohira,Tomonori Hirao,Keiya Isoda,Manabu Kurita,Makoto Takahashi,Taiichi Iki,Masakazu G Iwaizumi,Masahiro Miura

doi:10.3390/f11090955

Koji Matsunaga, Atsushi Watanabe + Show 9 more

Open Access

https://doi.org/10.3390/f11090955

Copy DOI

Abstract

Background and Objectives: To determine whether the progeny of pinewood nematode-resistant Pinus thunbergii Parl. clones selected in the southwestern region of Japan could be successful in reforestation in the northern region, we investigated the magnitude of the genotype–environment interaction effect on the resistance against Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle in P. thunbergii. Materials and Methods: We inoculated P. thunbergii seedlings of six full-sib families, with various resistance levels, with B. xylophilus in nurseries at three experimental sites in the northern and southern regions of Japan. All parental clones of the tested families originated from southwestern Japan, and selection of parental clones for resistance was performed in the same region. Sound rates after nematode inoculation were calculated, and survival analysis, correlation analysis and variance component analysis were performed. Results and Conclusions: Families with high sound rate in the southern region also showed a high sound rate in the northern region. In almost all cases, Spearman’s correlation coefficients for sound rates were more than 0.698 among sites. The variance component of the interaction between site and family was small compared to that of site and family separately. Thus, we conclude that the resistant clones selected in the southern region would retain their genetic resistance in the northern regions.

Highlights

Japanese black pine Pinus thunbergii Parl. is one of the major forestry species in Japan
To combat pine wilt disease (PWD), a national resistance breeding program of Pinus densiflora Sieb. et Zucc. (Japanese red pine) and P. thunbergii was started in southwestern Japan in 1978 as a part of an integrated pest management
M105 × A1 was the tallest family in Tohoku Regional Breeding Office (TBO), but was the fourth tallest family in Forest Tree Breeding Center (FTBC)

Summary

Introduction

Japanese black pine Pinus thunbergii Parl. is one of the major forestry species in Japan. In P. thunbergii forests, the disease has spread to the northern part of Japan [2,3,4]. (Japanese red pine) and P. thunbergii was started in southwestern Japan in 1978 as a part of an integrated pest management. Clones selected in the southwestern region of Japan could be successful in reforestation in the northern region, we investigated the magnitude of the genotype–environment interaction effect on the resistance against Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle in P. thunbergii. Materials and Methods: We inoculated P. thunbergii seedlings of six full-sib families, with various resistance levels, with B. xylophilus in nurseries at three experimental sites in the northern and southern regions of Japan. All parental clones of the tested families originated from southwestern Japan, and selection of parental clones for resistance was performed in the same region. Sound rates after nematode inoculation were calculated, and survival analysis, correlation analysis and variance component analysis were performed

Methods

Results

Conclusion