Induction of somatic embryogenesis and evaluation of genetic stability in regenerated plants of Magnolia dealbata

Abstract

The utility of plant tissue culture for the mass propagation of trees is well known, but continuous in vitro multiplication of plant material may increase the possibility of somaclonal variation; therefore, it is essential to evaluate the genetic integrity of regenerants from species-specific in vitro protocols prior to mass production and implementation. The objectives of this study were: 1) to determine the effect of 2,4-dichlorophenoxyacetic acid (2,4-D) concentration over two cycles of secondary somatic embryogenesis in Magnolia dealbata; and 2) to verify the genetic stability of the regenerants obtained. The embryogenic response was not significantly affected by the concentration of 2,4-D but did vary across cycles of induction. The addition of 4.52 μM 2,4-D induced the highest total number of embryos (100.5), the mean number of somatic embryos (25.1) and somatic embryos per explant (80.6). In both 2,4-D concentration (2.26 or 4.52 μM), genetic integrity between the donor and the propagated clones was 0.90, and the low genetic instability (≤ 0.10 in both PGR treatments) might be due to effect of cyclic somatic embryogenesis or the different response of the explants at stress in in vitro culture conditions. However, it is necessary to examine more cell lines and somatic embryogenesis cycles. Additional key words: 2,4-dichlorophenoxyacetic acid, in vitro culture, simple sequence repeats, somaclonal variation.