Abstract
Research on flowering in forest trees has pursued two main objectives: 1) developing methods for stimulating flowering of selected genotypes to accelerate progeny testing, and 2) hastening the production of genetically-improved seeds in seed orchards. Cultural techniques have been used to some extent in the past for these purposes, but the use of plant-growth regulators (PGRs), particularly the gibberellins (GAs), has been increasingly successful. GAs have been shown to induce flowering in most conifers, but GA application on an operational basis has been worked out for only a few species. GAs have been applied effectively by topical treatment, by stem or branch injections, and by foliar sprays. The timing and concentration of applied chemicals are important and vary from species to species. Another PGR, naphthalene-acetic acid, is synergistic with GAs in some species. Adjunct cultural treatments are often used in combination with treatment with GAs. The success of treatment with GAs is determined to some extent upon the stage of development of the treated plants. The endogenous PGRs regulating flowering are not completely known but it appears that the GAs, the cytokinins, and bascisic acid may all be changed by treatments which induce flowering. Improved techniques becoming available for measuring PGRs are beginning to stimulate research on the endogenous PGRs. The PGRs will continue to play a major role in stimulating flowering in forest trees.
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Bonnet-Masimbert, M., Zaerr, J.B. 2. The role of plant growth regulators in promotion of flowering. Plant Growth Regul 6, 13–35 (1987). https://doi.org/10.1007/BF00043948
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DOI: https://doi.org/10.1007/BF00043948