Field performance and characterization of two stable stevia mutants with increased biomass and rebaudioside - ‘A’ content

Stevia is a perennial herbaceous medicinal plant that has received commercial attention from the pharma industry because of its sweetening properties. In the present study, two Bidhan Stevia rebaudiana mutants (‘BSRV1’ and ‘BSRV2’) were selected (Source development). All major vegetative growth traits, steviol glycoside contents, and flow cytometry analyses were carried out for ‘BSRV1’ and ‘BSRV2’ along with the control (nonirradiated). The in vitro-regenerated mutants along with the control plantlets were initially ex vitro acclimatized successfully. The plantlets of ‘BSRV1’ exhibited exceptional field growth performance, followed by ‘BSRV2’. The ‘BSRV1’ plants after three months of field transfer produced the maximum (63.47 cm) plant height, number of shoots (6.40), number of branches (10.40), number of leaves (129.40), leaf area (13.84 cm2), fresh leaf yield (2.05 t ha-1) per single cutting, and dry leaf yield (0.38 t ha-1) per single cutting followed by ‘BSRV2’ and the control. The stability of the ploidy level of both mutants against the control was ascertained via flow cytometry. The results of the high-performance liquid chromatography analysis of rebaudioside-A were the highest for ‘BSRV1’ (95.45 mg g-1 DW), followed by ‘BSRV2’ (89.93 mg g-1 DW) and the control (65.30 mg g-1 DW). Stable mutants with distinct morphological traits and ameliorated rebaudioside-A content can be exploited as new genotypes by the growers and pharmaceutical industry.