IN-VITRO REGENERATION OF FOURWING SALTBUSH [ATRIPLEX-CANESCENS (PURSH) NUTT]

A successful, in vitro regeneration system for fourwing saltbush [Atri plex canescens (Pursh) Nutt,] has potential use for mass propagation a nd genetic engineering of this important range species, This system co uld be used as a vehicle for gene transfer and for genetic modificatio n of forage quality, stress tolerance, and biomass. The objectives wer e to develop an in vitro system for shoot production from both leaf di scs 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/mm(2) of leaf disc explants, Root organoge nesis was induced in 63% (168) of the shoots, using indolebutyric acid (IBA, 0.5 mg liter(-1)) and gibberellic acid (GA(3), 0.1 mg(-1) liter ) in a Murashige and Skoog (AIS) medium, Roots were also induced on sh oots 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 multiplic ation, the number of shoots generated ranged from 0.7 to 9.1 per expla nt. 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 specie s can be mass propagated in vitro.