Comparative regeneration in six bread wheat (Triticum aestivum L.) varieties from immature and mature scutella for developing efficient and genotype-independent protocol prerequisite for genetic improvement of wheat

Abstract

Hexaploid bread wheat, being highly recalcitrant, has been difficult to regenerate in vitro which limits the use of transgenesis and genome editing for its agronomic improvement and functional genomics. We have studied the comparative in vitro regeneration in six most important wheat varieties, namely, HD-2967, PBW-343, WH-1105, PBW-550, DBW-17, and WL-711, using immature vs mature scutellum. The regeneration response of varieties PBW-550, DBW-17, and HD-2967 has not yet been reported. The mature and immature scutella cultured on MS medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) (2 mg l−1) or dicamba (6 mgl−1), respectively, and maltose (30 gl−1) under dark conditions developed calli which subsequently on transfer to modified MS medium with double concentration of NH4NO3, zeatin (5.0 mgl−1), dicamba (0.1 mgl−1), AgNO3 (2.0 mgl−1), CuSO4 (2.5 mgl−1), and sucrose (30 gl−1) under light conditions regenerated into shoots. Immature scutellum showed 100% callus induction irrespective of varieties and regenerated a maximum of 15 shoots per callus in 90% cultures, whereas mature scutellum showed a maximum 80% callus induction, producing maximum 5 shoots only in 67% cultures. Thus, immature scutellum has been more responsive comparative to mature scutellum for inducing callus and shoot regeneration. Among all the six varieties, HD-2967 was the most regenerative, which can be explored further for improving wheat via genetic transformation studies.