Role of cytogenetic studies, protein electrophoresis and ISSR markers in assessment of genetic diversity in Stevia rebaudiana (Bertoni).

Abstract

Chromosome number was investigated in a number of strains of Stevia rebaudiana. The chromosomes were analyzed during mitosis and different stages of meiosis. All stevia strains were found to had 2n = 22. The number of bivalents at diakinesis was 11 for all the studied strains. Analysis of SDS-PAGE of soluble protein revealed complete similarity (100%) among the six strains of Stevia while two strains (broad and narrow leaves) are different in one band. Eight genotypes were assayed by inter-simple sequence repeat (ISSR) markers to differentiate and explore their genetic relationships. The level of polymorphism detected among the eight strains of stevia was 100.00% using inter simple sequence repeat (ISSR). A total of 231 clear bands were generated, out of which 34 (14.72 %) were unique bands. The total number of markers varied from 1 to 12 with a mean of 5.67 markers per primer.