A method for producing mature conifer somatic embryos, comprising:(a) culturing pre-cotyledonary conifer somatic embryos in, or on, a development medium comprising maltose as the sole source of sugar and 0 to less than 0.5 w/v% of gellan gum to form cotyledonary conifer somatic embryos and(b) culturing the cotyledonary conifer somatic embryos formed in step (a) in, or on, a maturation medium comprising sucrose as the sole source of metabolizable sugar in a concentration of 1 to 6 w/v%, and gellan gum in a concentration of between 0.5 and 1.5 w/v% for a period from one week to five weeks to produce mature conifer somatic embryos.
