Establishment of efficient in vitro culture protocol for wheat land races of Pakistan
The reliability of the production and presence of disease resistance especially rust has sparked a renewed interest in improving landraces and exploiting these in wheat variety development programs. In vitro culture is a pre-requisite for most of the tools of biotechnology. In this context, three Pakistani wheat (Triticum aestivum L.) land races viz., LLR-13, LLR-15 and LLR-16, having leaf rust resistance were assessed for in vitro plant regeneration response. Immature embryos were cultured on Murashige and Skoog medium supplemented with 2, 4, 6 and 8 mg/L of 2,4-Dichlorophenoxyacetic acid (2,4-D) for callogenesis and MS + zeatin riboside (1.0 mg/L) medium for regeneration of these calli. All three land races produced callus on all 2,4-D concentrations; higher doses (8 mg/L) being the most effective for callus fresh weight. However, there was a strong carry over effect of 2,4-D on regeneration capacity. Calli induced at 2 mg/L of 2,4-D showed the highest regeneration frequency for LLR-16, LLR-13 and calli of LLR-15 induced on 4mg/L were more regenerative. Overall, LLR-16 produced the maximum regenerants. Rooted plantlets were transferred to glasshouse for further evaluation.
Key words: Leaf rust, immature embryos, wheat land races, regeneration, Murashige and Skoog (MS) medium.