Genetic fidelity testing using SSR marker assay confirms trueness to type of micropropagated coconut (Cocos nucifera L.) plantlets derived from unfertilized ovaries.

Abstract

Background: In vitro culture techniques provide an excellent platform for the multiplication of recalcitrant species such as coconut and thereby increase the homogeneity of the plantations. Clonal fidelity is one of the most important pre-requisites in a micropropagation protocol of crop species especially those with long life spans. Objective: The present study was conducted in order to determine the genetic homogeneity of coconut plantlets derived from unfertilized ovaries through somatic embryogenesis. Method: Twenty randomly selected plantlets at acclimatization stage, from two mother palms were subjected to Simple Sequence Repeats analysis. Thirteen highly polymorphic microsatellite primers were used for the detection of genetic fidelity in the clonal plantlets and their respective parent. Results: These plantlets showed no apparent differences among themselves and were comparable with the respective mother palm in the Simple Sequence Repeats analysis. The results obtained from this study suggest that there is no somaclonal variation or genetic instability occurring in plantlets that are regenerated from ovary explants. Conclusion: The absence of any sign of somaclonal variation suggests that somatic embryogenesis protocol did not induce the changes in gene structure, which had remained stable throughout the period that had been maintained in vitro. Determination of genetic fidelity of in vitro plants proved the suitability of regeneration protocol for large scale micropropagation applications for coconut.