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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #147665

Title: APPLICATION OF ECTOMYCORRHIZAL FUNGI IN VEGETATIVE PROPAGATION OF CONIFERS

Author
item NIEMI, KAROLIINA
item Scagel, Carolyn
item HAGGMAN, HELY

Submitted to: Fourth International Conference on Mycorrhizae
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2003
Publication Date: 8/4/2003
Citation: Niemi, K., Scagel, C.F., Haggman, H. APPLICATION OF ECTOMYCORRHIZAL FUNGI IN VEGETATIVE PROPAGATION OF CONIFERS. Plant Cell Tissue and Organ Culture. 2004. (78) p. 83-91

Interpretive Summary: In forestry, vegetative propagation is important for production of selected genotypes and decreasing selection cycles in genetic improvement programs. In vivo cutting production and the in vitro methods of organogenesis and somatic embryogenesis are applicable with conifers. However, with most coniferous species these methods are not yet suitable for commercial application. Large-scale production of clonal material using cuttings or organogenesis is hindered by problems during rooting phase and difficulties in the maturation and conversion phases limit the use of somatic embryogenesis. Inoculation with ectomycorrhizal (ECM) fungi is a potential tool to improve vegetative propagation of conifers. Inoculation with specific fungi enhances root formation and/or subsequent root branching of in vivo cuttings and in vitro adventitious shoots. Germination of somatic embryos and subsequent root growth can also be improved by the use of ECM fungi. In addition, inoculation can increase the tree¿s ability to overcome stress related to transfer from in vitro to ex vitro conditions. Specific interactions between fungal strains and vegetatively propagated tree clones are key factors in the use of ECM fungi in vegetative propagation. Fungal-specific factors that influence rooting responses to inoculation may include plant growth regulator production, modification of rooting environment, and interactions with beneficial microbes. A combination of these factors may act synergistically to result in positive responses in compatible tree genotypes.

Technical Abstract: In forestry, vegetative propagation is important for production of selected genotypes and decreasing selection cycles in genetic improvement programs. In vivo cutting production and the in vitro methods of organogenesis and somatic embryogenesis are applicable with conifers. However, with most coniferous species these methods are not yet suitable for commercial application. Large-scale production of clonal material using cuttings or organogenesis is hindered by problems during rooting phase and difficulties in the maturation and conversion phases limit the use of somatic embryogenesis. Inoculation with ectomycorrhizal (ECM) fungi is a potential tool to improve vegetative propagation of conifers. Inoculation with specific fungi can enhance root formation and/or subsequent root branching of in vivo cuttings and in vitro adventitious shoots. Germination of somatic embryos and subsequent root growth can also be improved by the use of ECM fungi. In addition, inoculation can increase the tree¿s ability to overcome stress related to transfer from in vitro to ex vitro conditions. Specific interactions between fungal strains and vegetatively propagated tree clones are key factors in the use of ECM fungi in vegetative propagation. This indicates that multiple rooting factors exist in this interaction that complicate the predictability of the response to inoculation. Fungal-specific factors that influence rooting responses to inoculation may include plant growth regulator production, modification of rooting environment, and interactions with beneficial microbes. A combination of these factors may act synergistically to result in positive responses in compatible tree genotypes.