Genetic homogeneity of guava plants derived from somatic embryogenesis using SSR and ISSR markers

To evaluate genetic homogeneity of 1-year-old guava (Psidium guajava L.) plants developed from in vitro somatic embryogenesis, DNA from leaf tissues of seven randomly selected plants along with the mother plant, was isolated and subjected to molecular analysis. A total of six Simple Sequence Repeat (SSR) primer pairs, producing reproducible and clear bands ranging from 100 to 300 bp in size, resulted in amplification of single band (allele), corresponding homozygous individuals. Moreover, of 10 different inter-simple sequence repeat (ISSR) primers screened, six produced resolvable, reproducible and scorable bands. All these ISSRs produced a total of 25 bands, ranging between 300 and 1,200 bp length, and the number of scorable bands, for each primer varied from three to six with an average of 4.1 bands per primer. The amplification products were monomorphic across all the micropropagated plants produced by all SSR and ISSR primers applied. The monomorphic banding pattern in micropropagated plants and the mother plant confirms the genetic homogeneity of the in vitro raised plants and demonstrates the reliability of our in vitro propagation system for guava.