Embryo-rescue culture of the ‘Galia’ muskmelon (Cucumis melo L. var. reticulatus Ser.) male parental line

In order to obtain a reliable embryo-rescue technique for wild type (WT) and transgenic ‘Galia’ muskmelon male parental line we evaluated three distinct parameters: nutrient media (E20A basic medium and E21, with six new supplements), two culture systems (removing the embryo from the seed or intact seed), and the use of embryos from fruit at increasing days post pollination (DPP). Transgenic muskmelon plants with the ACO gene in antisense orientation were obtained using a protocol previously described. Fruits were harvested at 4, 10, 17, 24 and 30 DPP. The embryos were either removed from the seeds or left in the seeds and placed in E-20A or E-21 medium for 30–35 days. Seedlings (well developed cotyledon) from all treatments were transferred to E-21 elongation medium, incubated 5 weeks, and transferred to soil to evaluate growth. The efficiency of this technique was greater as embryo age (DPP to rescue the embryo) was increased. Embryos 17–30 DPP had the greatest efficiency for embryo rescue, although embryos could be rescued as early as 4 DPP. The number of rescued embryos using an improved medium (E-21) was greater than E-20A basic medium. Survival efficiency rate was the same for WT and transgenic embryos. We have obtained a competent embryo-rescue technique for WT and transgenic ‘Galia’ male parental line with better efficiency rates than others previously reported.