Effect of growth regulators on enhanced plant regeneration from embryo derived calli of wheat (Triticum aestivum L.)

The present studies were conducted to induce calli from mature embryos of Triticum aestivum L. for establishing an efficient regeneration system in four local wheat cultivars viz. Chakwal-97, Margalla-99, C-591 and Kohsar-95. It was found that 100% Clorox was effective to minimize contamination but callus quality was excellent when 70% Clorox was utilized. The callus induction frequency was observed on both media viz., N6 and MS but N6 media was better than MS medium. Similarly media supplemented with 3.5 mg/l 2,4-D was effective in all of the concentrations as it showed the highest (100%) callus induction frequency and took shortest time (3 weeks) whereas the callus quality was highest at 2 mg/l but it took longer time (5-7 weeks) and showed less frequency (41%). Among the four genotypes, Chakwal-97 showed 83.3% in all the conditions whereas C-591 showed 41.6% in this regard. The other two varieties showed average type (75-80%) of callus induction frequency. After three weeks, these calli were transferred to maintenance media (MS) supplemented with 2 mg/l 2, 4-D and sorbitol to proliferate the callus. Then ten different combinations of BAP (6-benzyl aminopurine) and IAA (3-indole acetic acid) were prepared with MS basic salts and vitamins. Secondary callus obtained from proliferation medium of each variety was inoculated on each of these combinations to check regeneration. The combination having 0.5mg/l BAP and 0.1 mg/l IAA had 83% regeneration. The combinations with higher concentrations of IAA had only root development or small roots but shoots were totally absent. The combinations with higher concentrations of BAP had both rooted and shoot induction. Then four combinations of BAP and NAA on MS media were used in which 0.5 mg/l BAP along with 0.2 mg/l NAA was found better than the other three combinations, but this was not as effective as combinations of BAP and IAA. Similarly, four combinations of kinetin and IAA were used in which 1.0 mg/l kinetin along with 0.1 mg/l IAA was found better. All these studies showed that N6 medium supplemented with 3.5 mg/l 2,4-D was the best for callus induction in wheat, whereas MS medium with 2 mg/l 2,4-D is better for proliferation of callus and MS supplemented with 0.1 mg/l IAA and 0.5 mg/l BAP was the more efficient media for regeneration, while the callus age would not be more than six weeks.