| Abstrakt: |
Chez les ignames, une maladie ? virus (Yam mosaic virus, YMV) affecte gravement la culture et r?duit les ?changes de ressources g?n?tiques. La r?g?n?ration de plantes sans virus a ?t? recherch?e, chez Dioscorea trifida L, par culture d'apex de vitroplants issus de boutures nodales de mat?riel contamin?. Le d?veloppement in vitro a ?t? r?alis? en 3 phases : - d?p?t et reprise du fonctionnement de l'apex sur solution min?rale N 30 K de Margara, comportant une cytokinine (BAP ? 8,88 ?mol/l) et une auxine (AIB ? 0,049 ?mol/l) - allongement et multiplication des pousses feuill?es sont favoris?s par un passage sur une solution min?rale de Murashige et Skoog avec macro?l?ments dilu?s de moiti? (MS/2) avec BAP (0,88 ?mol/l) et AIB (0,049 ?mol/l) - enracinement des vitroplants de longueur suffisante. Il est induit par trempage dans une solution de saccharose (80 g.l-1) et ANA (2,67 ?mol/l). Les vitroplants sont transf?r?s directement en substrat horticole. L'utilisation du test immunoenzymatique ELISA indique que 27% des plantes issues de culture d'apex in vitro sont ainsi d?barrass?es du YMV. Cleaning the Dioscorea trifida L yam from yam mosaic virus (YMV) through apices in vitro culture. The Dioscorea trifida L yam is particularly susceptible to the yam mosaic virus (YMV) which severely affects most yam cultures and reduces the exchange of genetic resources. Healthy plants have been sought through apical meristem tip in vitro culture of vitroplantlets obtained from nodal explants of diseased material. This was performed in 3 phases : 1) Outgrowth or organisation of the apex over a paper bridge (fig 1) on a mineral solution of Margara ("N 30 K"), including a cytokinin (BAP 8.88 ?mol/l, fig 2) an auxin (IBA 0.049 ?mol/l) and gibberellin (GA32.9 ?mol/l); 2) Lengthening and multiplication of leafed buds (fig 3) benefited from one subculture on a mineral solution of Murashige and Skoog with half diluted macro elements (MS/2, table II) BAP (0.88 ?mol/l, table III) and IBA (0.049 ?mol/l and gibberellin (0.29 ?mol/l); 3) Shoots which had grown enough were rooted (fig 4) by dipping in a solution of sucrose (80 g/l) and ANA (2.67 ?mol/l, fig 5). The vitroplantlets were directly transferred in horticultural substrate. Those not cleaned could not then express their virus symptoms (fig 6). The application of the immuno enzymatic test Elisa established that 27% of the plants grown from in vitro apex culture are free from YMV (fig 7). |
