Báo cáo khoa học: In vitro propagation of interspecific hybrids

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Báo cáo khoa học: "In vitro propagation of interspecific hybrids" in AlnusIn vitro of interspecific hybrids propagationH. Sbay, J. Guillot, P. Danthu D. PratLaboratoire de Genetique des Populations d i4rbres Forestiers, ENGREF, 14, Girardet, F-54042 rueNancy, France used: A. glutinosa, A. cordata, A. incana andIntroduction A. rubra. The best performing and plastic hybrids (Prat, 1988) were studied: A. glutinosaAlnus species show promise for afforesta- x A. incana (GI), A. rubra x A. glutinosa (RG), A. cordata x A. glutinosa (CG) and A. cordata xtion and wood production, particularly on A. incana (CI).. )poor soils, since they are fast-growing and Shoots cut from selected trees were soakednitrogen-fixing trees. This allows mixed in fungicide (Benlate, 0.15%) for 24 h and thenplantations with benefits to the main disinfected with calcium hypochlorite (7% foraccompanying forest species by nitrogen 10 min) and kept on nutritive medium con-supply. The genus Alnus includes some taining sucrose for 1 day. Afterwards, shoots were disinfected with a mercuric chloride solu-fast-growing species adapted to various tion (0.1 %, for 10 min.). Nodes were separatedecological situations (Martin, 1985). Gene- in an anti-oxidative solution (2.8 mM dithiothrei-tic improvement programs are being de- tol, 2.8 mM cysteine hydrochloride, 2.8 mMveloped to produce effective clonal varie- citrulline, 2.5 mM sodium ascorbate and 0.1%ties able to grow under various ecological polyvinyl pyrrolidone 40 000) to avoid the browning of explants, and finally put into cultureconditions. Controlled hybridizations (in- medium. Some aspects of in vitro culture weretraspecific and interspecific) were carried tested to improve the techniques.out to obtain improved progenies fromwhich trees will be selected. Field trialsshow good performance of interspecifichybrids (Prat, 1988). The latter should be Resultspropagated to confirm their superiority andthen be distributed afterwards as selectedclones. In vitro micropropagation is Basal culture medium for in vitro cultureapplied because of the poor developmentof cuttings. Three media were compared for the growth of shoots: woody plant medium (WPM, Lloyd and McCown, 1980), Mura-Materials and Methods shige and Skoog (1962) medium (MS), and Quoirin and Lepoivre (1977) medium (QL) supplemented with WPM micronu-Early selection of trees (at age 4 yr) was carried trient and addenda. Glucose (15 g ), I I- ’out in progeny trials; 4 progenitor species wereindolebutyric acid (IBA, 2.5 pM) and ben- glucose, fructose, galactose, sucrose,zylaminopurine (BAP, 2.5,uM) were added mannitol and sorbitol. Carbohydrates wereto the semi-solid media. added to complete WPM supplemented with IBA (1.0 !M) and agar. Each tested clone (CI, CG and RG)grew the best on WPM. RG clones The most extensive growth and num-showed the least growth. The level of IBA bers of roots and leaves (Table I) werewas reduced to 0.5 pM to avoid callus for- observed in media containing either glu-mation at the explant basis. The suppres- cose, galactose or fructose. Sucrose wassion of BAP allowed multiplication by elon- not the best carbohydrate source. Thegation. ...