Techniques to Differentiate Zygotic and Nucellar Seedlings in Polyembryonic Fruit Crops

Different methods are in use for differentiating zygotic and nucellar seedlings in these polyembryonicfruit crops which include morphological methods, isozymes, RAPD, AFLP, TLC, ISSR, SSR etc. Polyembryonic varieties produce seeds which originate zygotic and nucellar plantlets. Zygotic plantlets are sexual whereas nucellar plantlets come from the maternal tissues which are assexual plantlets. Therefore, nucellar plantlets are preferred for grafting, because they maintain the same genetic background of the rootstock mother-plant whereas zygotic plantlets preferred for breeding programmes because they do not maintain same genetic background of the mother plant. Identifying the sexual embryo in each hybrid seed, in order to preserve only the nucellar ones, would help to maintain the genetic characteristics of the rootstock and also to progress fruit breeding by avoiding the nucellar ones to advance generations.

Nucellar plantlets are preferred for grafting.

Zygotic plantlets preferred for breeding programmes.

Morphological methods, Isozymes, RAPD, AFLP, TLC, ISSR and SSR used for differentiation of zygotic and nucellar seedlings