Development of an efficient and reproducible regeneration system in wheat (Triticum aestivum L.)

The availability of reproducible regeneration system through tissue culture is a major bottleneck in wheat improvement program. The present study has considered to develop an efficient callus induction and regeneration system using mature and immature embryos as explants in recently released agronomically superior spring wheat varieties. An efficient sterilization process was standardized using 0.1% HgCl₂ and 70% ethanol for both seeds and embryos. The maximum possible combinations of plant growth regulators (PGRs) were evaluated for their effect on different wheat regeneration processes through tissue culture starting from callus to root induction. Picloram is found as an effective auxin with 87.63-98.67% callus induction efficiency in both explants. Supplementation of CuSO₄ along with 2,4-D, zeatin in regeneration medium significantly enhanced the multiple shoot induction. The shoot development was achieved using full strength Murashige and Skoog's (MS) medium and root induction using half MS medium without PGRs. The optimized medium and method has resulted up to 100% regeneration irrespective of the genotype used with high reproducibility. Thus, the standardized regeneration system can be used in the regeneration of healthy plants from embryos rescued from interspecies crosses, transgenic production, induced mutation breeding and recently developed genome editing techniques for the procreation of wheat plants having novel traits.