EFFECT OF CULTIVARS AND CULTURE MEDIUM ON CALLUS FORMATION AND PLANT REGENERATION FROM MATURE EMBRYOS OF WHEAT (TRITICUM AESTIVUM L.)

Experiments were conducted to investigate callus induction, plant regeneration and somaclonal variations in 9 locally developed wheat cultivars viz., Ghaznavi-98, Fakhr-e-Sarhad, Inqilab-91, Tatara, Takbeer, Margalla, Pirsabak-85, SARC-3 and Khattakwal and one line from ICARDA (ICP-3) on hormones free and various concentrations of 2,4-dichorophenoxyaceitc acid (2, 4-D) in LS/MS medium. Cultivars responded differently to medium and 2, 4-D concentration for callus induction. Maximum calli induction (67.5%) was noted in ICP-3 followed by SARC-3 (65.5%) on MS. In our studies MS medium was more effective for all the wheat cultivars compared with LS medium for callus induction. When the effect of different concentration of 2, 4-D on callus induction was studied, MS medium containing 2 mg l(-1) 2, 4-D produced the greatest number of calli. Morphology of these cultivars were further studied on both LS/MS medium containing only 2 mg l(-1) 2, 4-D. Embroyogenic and non-embryogenic calli were observed in all the cultivars studied. Embryogenic calli were generally compact and rapidly growing whereas non-embryogenic calli were loose and slow growing. For regeneration, LS/MS medium was supplemented with various combinations of IAA and BAP. Significant differences were detected in plant regeneration, culture efficiency and regeneration capacity when mature embryos of 9 locally developed cultivars and one line from ICARDA (ICP-3) were compared. Six cultivars responded efficiently to LS medium while four showed better performance on MS medium for plant regeneration. Majority of the somaclones regenerated in this study were found to be inferior for agronomic traits except plant height, days to heading and maturity when compared with their respective controls. Our results showed that callus derived from this wheat cultivar is amendable and could be used for genetic transformation studies.