Assessment of genetic fidelity of somatic embryogenesis regenerated guava (Psidium guajava']java L.) plants using DNA-based markers

An efficient somatic embryogenesis protocol for plantlet regeneration of the commercially valuable, and nutritionally important, crop guava (Psidium guajava L.) has been established. The immature zygotic embryos were targeted as an explant source for inducing somatic embryogenesis and plant regeneration, using four commercial cultivars (Allahabad Safeda, Lalit, Sardar and Shweta). The plantlets regenerated were assessed for genetic fidelity using random amplified polymorphic DNA (RAPD), inter simple sequence repeats (ISSR) and simple sequence repeat (SSR) molecular markers. A total of 2171 scorable bands were obtained using RAPD, ISSR or SSR, ranging from 300-3500, 250-3000 and 150-280 bp, respectively. No polymorphism was observed among the somatic embryogenesis regenerated plants, compared with respective donor mother plants. The profiles generated based on the three marker systems were found to be highly uniform and approximately 99% bands were monomorphic. This high degree of genetic uniformity (as assessed using the markers) in the somatic embryogenesis regenerated plants indicates genomic stability was maintained through the regeneration protocol. The somatic embryogenesis regenerated plants were hardened and transferred to the field for acclimatization, of which 80% plantlets survived, with all being phenotypically similar to the donor mother plants. We conclude that the RAPD, ISSR and SSR markers were informative and potentially useful in confirming the uniformity assessment of somatic embryogenesis regenerated plants.