tailieunhanh - Báo cáo khoa học: "A critical review of larch hybridization and its incidence on breeding strategies"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "A critical review of larch hybridization and its incidence on breeding strategies. | 141 Ann. Sci. For. 1989 46 141-153 Elsevier INRA Review article A critical review of larch hybridization and its incidence on breeding strategies . Pâques INRA Station d Amelioration des Arbres Forestiers Centre de Recherches Forestieres Ardon F-45160 Olivet France received 28-2-1988 accepted 26-10-1988 Summary Hybrid larch Larix X eurolepis Henry superiority over the parental species Larix decidua Mill and Larix kaempferi Lamb. Carr. has been described by many tree breeders. This superiority concerns not only growth characteristics but also several economically important traits. In the literature there is some ambiguity regarding the 3 following concepts hybridization hybrid superiority and heterosis. In particular the superiority of hybrid larch has been claimed in many studies as due to heterosis. A detailed review of published results does not permit a decisive opinion on the subject as most of the results are based on punctual and limited observations. The interest in hybridization is not restricted to hybrid vigor but also includes combination and transfer of favorable characteristics. Several larch improvement strategies based on inter- and intraspecific hybridization are discussed. Reciprocal recurrent selection seems particularly attractive. Nevertheless none of the present strategies including the Fl generation as a breeding population can be excluded. Precise knowledge on genetic properties of traits selected for are required before any firm recommendation can be made. There is an urgent need for well designed long-term experiments set up on several sites to obtain more insight into these delicate questions. Use of a two-level factorial mating design is recommended in particular to avoid some of the approximations made in past experiments. Moreover valuable information on genetic parameters . combining ability heterosis will be gained at both intra- and inter-species and intra- and inter-population levels and may help tree breeders in their choice