Optimizing sterilization conditions and growth regulator effects on in vitro shoot regeneration through direct organogenesis in Chenopodium quinoa

Abstract

Chenopodium quinoa Willd. is known as a multipurpose crop that could be employed as an alternative on unsuitable lands with limited water resources such as arid and semi-arid regions. However, the biggest problem in cultivating this plant is contamination by viruses that are carried by quinoa seeds and cause diseases. Therefore, in vitro propagation methods could be applied to produce virus-free plants. The capacity of sodium hypochlorite to sterilize seeds and the regeneration potential of cotyledonary node segments were studied on Murashige and Skoog (MS) medium consisting of various concentrations of cytokinins and auxins either alone or in combinations. Although no contamination was observed after sterilization with 20% sodium hypochlorite and 10 and 15 min of immersion; with 25% sodium hypochlorite and 5, 10, and 15 min of immersion, the highest seed germination (100%) was obtained after sterilization with 20% sodium hypochlorite for 5 minutes. MS medium supplemented with 2.0 mg/l 6-benzylaminopurine (BAP) had the highest shoot induction frequency (93.33%) with an average of 4.96 shoots per node explant. This study is the first report of an appropriate and effective in vitro regeneration protocol for Chenopodium quinoa via direct organogenesis through cotyledonary node explants derived from axenic-seedlings, which can be effectively employed for the genetic manipulations and exploitation of active biomolecules of this valuable plant. This protocol can also increase the speed of quinoa breeding programs.