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Techniques were developed in the early 1900´s enabling unripe seed or embryo´s from adult plants to be rescued and to
form small plants. This was done mainly with seed which had a very long dormancy period. With continuing developments in tissue culture this technique was used to save embryos from ovules, which had been fertilized but had never developed into viable seed on the mother plant. Initially, complete ovaries were put in tissue culture whereby seedlings were obtained from embryos which would have died in a later stage of development. Saving embryos that died in an early stage of development came at a later stage, resulting in high-tech ovule- and embryo-culture techniques. Often a combination of these techniques is used: parts of the ovaries are put in tissue culture following which ovule and/or embryo culture is applied. there are 4 basic techniques used;

(1) Ovary Slice Culture. The ovary is transversely sectioned into 6-8 slices of 3-4 mm thickness and polarly placed on the ovary slice culture medium,

(2) Ovule with Placenta Culture. Ovules with placenta are excised from ovaries and incubated on MS medium, ovules are excised individually from placenta and cultured on ovule culture medium,

(3) Young Single Ovule culture. young ovules are excised from ovaries without placenta and ovary tissue and incubated on a Murishige & Skoog medium until germination, and finally

(4) Embryo/embryo Sac culture method. Embryo and/or embryo sacs are removed from the ovules under a dissecting microscope and cultured on the embryo culture medium until germination, depending on genotype.

embryo rescue requires sterile tissue culture conditions & chemicals and can be difficult and time consuming