Increase gelrite concentration improves somatic embryo maturation in hybrid larch

International audience; Development of clonal propagation method, such as somatic embryogenesis, has numerous applications such as massproduction of genetically improved plants. Since the 90’s, researchers at INRA have engaged research on SE in Larix species (Larix eurolepis, Larix marschlinsii), resulting in a controlled protocol (Lelu and Label 1994). If the positive effect of high gellan gum concentration on somatic embryo maturation is well-known in pine species (Lelu-Walter et al., 2006, 2008), but had not been previously demonstrated with hybrid larches. Maturation of somatic embryos was greatly improved when embryonal masses were placed on medium supplemented with 0.2M sucrose, 60μM ABA containing high concentration of gellan gum (8gl-1). Increasing the gellan gum concentration improved both the quantity and quality of the somatic embryos by reducing EM proliferation and giving rise to well-shaped somatic embryos which subsequently germinated and developed into plantlets. Somatic embryos maturated in presence of high gellan gum, presented reduced moisture content, increase of their dry weight that could resulted from an increase of their protein content (soluble and total part). Gels 2D were realised at 8 weeks, following by LC-MS/MS analysis to identify proteins. In conclusion, hybrid larch SE should influence breeding strategies by offering an alternative tool for accelerated production of large quantities of plants for clonal tests. The improved protocol was applied for the propagation of the new hybrid variety REVE-VERT. Integration of SE into the breeding programme is now undertaken (Lelu-Walter and Pâques 2009).