Uses of Plural Embryos
Although the basic that trigger causes polyembryony are not fully understood, there has been no dearth of interest in exploiting supernumerary embryos. The multiple embryos within a seed can be haploid, diploid or triploid. Haploid seedlings can be utilized for obtaining homozygous diploid forms by doubling the chromosome complement by a polyploidization agent. Such haploids and double haploids or homozygous diploids ate of immense use in breeding superior crop varieties and hybrids. Adventive embryos are useful in agriculture and horticulture because they are genetically uniform and generally disease free. In view of the utility of polyembryony, there have been several attempts to induce it artificially in those plants which are not normally polyembryonate or where the phenomenon occurs only occasionally.
Environmental factors are often responsible for induction of polyembryony. However, application of PGRs has not proved successful in inducing polyembryony. During the last three decades tissue in culture technology, involving excision of a desired tissue or organ and growing it on a nutrient medium under sterilized conditions, has been highly successful. It has helped in large scale propagation of plantlets obtained from vegetative or reproductive parts of several plants of agricultural and horticultural- importance. Plantlets can now be obtained from the diploid tissues of nucellus or embryo or even from haploid micropores and triploid endosperm. Because of the wider application of tissue culture methodology, early interest in induction of polyembryony in field grown plants has died down.