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Outbreeding Depression Caused by Intraspecific Hybridization Between Local and Nonlocal Genotypes in Abies sachalinensis

Authors

  • Susumu Goto,

    Corresponding author
    1. Experimental Station at Tanashi, The University Forests, Graduate School of Agricultural and Life Sciences, University of Tokyo, Midori-cho 1-1-8, Nishi-Tokyo, Tokyo 188-0002, Japan
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  • Hayato Iijima,

    1. Laboratory of Silviculture, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo 060-8589, Japan
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    • Present address: Yamanashi Forest Research Institute, 2290-1 Saishoji, Masuho, Yamanashi 400-0502, Japan

  • Hitomi Ogawa,

    1. University Forests in Hokkaido, The University Forests, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yamabe, Furano, Hokkaido 079-1561, Japan
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  • Kazumi Ohya

    1. University Forests in Hokkaido, The University Forests, Graduate School of Agricultural and Life Sciences, University of Tokyo, Yamabe, Furano, Hokkaido 079-1561, Japan
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S. Goto, email gotos@uf.a.u-tokyo.ac.jp

Abstract

To evaluate the effects of intraspecific hybridization of local and nonlocal genotypes on growth traits of progeny in Abies sachalinensis, we performed reciprocal crossing between nonlocal trees in a high-elevation zone (1,100–1,200 m asl) and local trees in a low-elevation zone (530 m asl) in Hokkaido, northern Japan, in 1979 and established a common garden experiment using local × local (female × male ), local × nonlocal , nonlocal × local , and nonlocal × nonlocal progeny in the low-elevation zone in 1986. Survival, height, diameter at breast height (dbh), needle nitrogen content, specific leaf area (SLA), and needle area per shoot diameter (NA) of 25-year-old progeny were measured in 2005. The survival rate was consistently high (>85% on average). Reductions in height and dbh were apparent in F1 hybrids compared with local × local progeny. Furthermore, outbreeding depression was significant in height growth of nonlocal × local F1 hybrids and in dbh of both F1 hybrids. Reductions in growth traits may be related to morphological needle traits, such as the low values of SLA and NA. Elevation guidelines for A. sachalinensis seed zones are discussed to ensure the long-term viability of both restored and native populations.

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