Somatic embryogenesis of rose (Rosa sp.)

Abstract

Somatic embryogenesis (SE) offers vast potential as a method for clonal propagation of roses. By this method, tissue from an elite plant is cultured in vitro and induced into an embryogenic state, in which bipolar somatic embryos are formed. The somatic embryos are capable of regenerating whole plants that are genetically identical to the plant used as the original tissue source. Although somatic embryogenesis holds several advantages over conventional means of propagation, SE technology requires improvement before use on a commercial scale. This thesis describes studies aimed at developing somatic embryogenesis technology for roses.

A suitable methodology for SE of the commercially valuable rose cultivar 'Livin' Easy' ( Rosa hybrida L.) was developed. This is the first report of SE induction in the cultivar 'Livin' Easy'. Murashige and Skoog basal medium supported growth and promoted successful induction of embryogenic tissue when supplemented with plant growth regulators, whereas Woody Plant Medium and plant growth regulator-free medium did not. The synthetic auxin 2,4,5-trichlorophenoxyacetic acid was successful in inducing SE at higher rates and over a greater concentration range than the commonly employed 2,4-dichlorophenoxyacetic acid. This was the first report of the utilization of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) for the induction of SE in rose. Somatic embryos successfully converted into plantlets at high rates up to 95%. Embryogenic tissue occurred on 60% of the plantlets, a phenomenon referred to as recurrent somatic embryogenesis.