In vitro regeneration of fourwing saltbush [Atriplex canescens (Pursh) Nutt.]

Abstract

A successful, in vitro regeneration system for fourwing saltbush [Atriplex canescens (Pursh) Nutt.] has potential use for mass propagation and genetic engineering of this important range species. This system could be used as a vehicle for gene transfer and for genetic modification of forage quality, stress tolerance, and biomass. The objectives were to develop an in vitro system for shoot production from both leaf discs and axillary buds, and induce root production. Shoot organogenesis (265 shoots) from leaf disc explants was accomplished at rates of 12.3 shoots/disc or 1.7 shoots/mm2 of leaf disc explants. Root organogenesis was induced in 63% (168) of the shoots, using indolebutyric acid (IBA, 0.5 mg liter-1) and gibberellic acid (GA3, 0.1 mg-1 liter) in a Murashige and Skoog (MS) medium. Roots were also induced on shoots placed in soil. Survival of both shoots and plantlets transferred to soil was 65%. Plantlets transferred to a hydroponic solution were twice the height of plantlets grown in soil. For axillary bud multiplication, the number of shoots generated ranged from 0.7 to 9.1 per explant. Roots were induced on 63% of the shoots, and 58% survived transfer to soil. The successful production of plantlets using both leaf-disc and axillary-bud methods demonstrates that this important range species can be mass propagated in vitro.