Abstract
Immature embryos are preferred explant source to get regeneration frequency compatible for genetic transformation in wheat. Under natural conditions, immature embryos can be obtained only once a year. Either controlled conditions to grow wheat in off season should be developed or alternative explant should be optimized. To develop mature embryos as explant, two commercial wheat varieties "AARI-11" and "Galaxy-13" were used for the development of regeneration system. Seeds were imbibed with five different concentrations of 2,4-D for 24 h. Embryos were isolated from imbibed seeds, subjected to seven callus induction media (CIM) containing different commercial auxins, and regeneration was achieved on two regeneration media (RM). Effects of genotypes, 2,4-D in imbibition solutions, CIM, and their interactions were studied. Imbibition produced significant effects on callus induction and embryogenesis. Imbibition solution with 8 mg/L 2, 4-D and CIM4 (2,4-D+Dicamba as growth regulator) was found to be most favorable combination for callus induction, and embryogenesis. Both regeneration media responded excellent for regeneration with 81.10% and 80.62% regeneration frequency. Our results also showed that this is not only the regeneration media but also the genotype, CIM and imbibition solutions that played their role for embryogenic callus induction and regeneration. To further improve regeneration the effects of starvation stress, and extended time at CIM were analyzed for embryogenesis induction. The best embryogenesis was observed after 3 weeks of stress and 9 weeks old calli maintained on CIM through sub-culturing. (C) 2017 Friends Science Publishers