Application of Embryo Culture
1. Rescuing Embryos from Incompatible Crosses:
In Interspecific and Intergeneric hybridization programmes, incompatibility barriers often prevent normal seed development and production of hybrids. Although there may be normal fertilization in some incompatible crosses, embryo abortion results in the formation of shrivelled seeds. Poor and abnormal development of the endosperm caused embryo starvation and eventual abortion. Isolation of hybrid embryos before abortion and their in vitro culture may prevent these strong post-zygotic barriers. The most useful and popular application of embryo cultures is to raise rare hybrids by rescuing embryos of incompatible crosses.
2. Overcoming Dormancy and Shortening Breeding Cycle:
Long, periods of dormancy in seeds delay breeding works, especially in horticultural and crop plants. Using embryo cultures techniques the breeding cycle can be shortened in these plants. For example, the life cycle of Iris was reduced from 2-3 years to less one year. Similarly, it was possible to obtain two generations of flowering against one in Rosa sps. Germination of excised embryo is regarded as a more reliable test for rapid testing of viability in seeds, especially during dormancy period.
3. Overcoming Seed Sterility:
In early ripening fruit cultivars, seed do not germinate because their embryos are still immature. Using the embryo culture method it is possible to raise seedling from sterile seeds of early ripening stone fruits, peach, apricot and plum.
‘Makapuno’ coconunts are very expensive and most relished for their characteristics soft fatty endosperms in place of liquid endosperm in place of liquid endosperm. Under normal conditions the coconut seeds fail to germinate. Guzman et.al (1971) obtained 85% successes in raising field- grown makapuno trees with the aid of embryo cultures.
4. Production of Monoploid:
An embryo culture has been used in production of monoploids of barley. With the cross Hordeum vulgare , fertilization occurs normally but thereafter chromosomes of H.bulbosum are eliminated, resulting in formation of Monoploid H. vulgare embryo which can be rescued by embryo cultures.
5. Clonal Micropropagation:
The regenerative potentials is an essential pre-requisite in non-conventional methods of plant genetic manipulations. Because of their juvenile nature, embryos have a high potential for regeneration and hence may be for in vitro clonal propagation. This is especially true of conifers and graminaceous members.
Both organogenesis and somatic embryogenesis have been induced in major cereals and forage grasses form embryonic tissues. Generally, callus derived from immature embryos of cereals has the desired morphogenetic potential for regeneration and clonal propagation.