Effect of picloram and 2,4-D on plant regeneration from mature and immature embryos of moroccan durum wheat varieties

Abstract

An efficient genetic transformation protocol is a fundamental requirement for high regeneration capacity from cultivated durum wheat (Triticum durum) varieties. In this study, wereportedtheeffectsoftwoauxins,2,4-dichlorophenoxyaceticacid(2,4-D)and4-amino-3,5,6-trichloropicoli nicacid(picloram), at a concentration of 2 mg/Laloneandincombination on the embryogenic callus and plantlet regeneration of four durum wheat varieties (Amria, Chaoui, Marouane, and Tomouh) using mature embryos (MEs) and immature embryos (ImEs). Significanteffectsofvariety,culturemedium(theauxinused),andvariety-mediuminteraction were observed on the callus weight and plantlet regeneration of both MR and ImE explants. The medium used for callus induction significantly affected plantlet regeneration (p < 0.001). Comparedto2,4-D, picloram led to a higher plantlet regeneration rate in both ME and ImE explants (19.8% and 40.86%, respectively). Plantlet regeneration also varied significantly depending on the variety and medium used. PicloramledtohighplantletregenerationofbothME and ImE explants in all varieties except Tomouh, which showed high plantlet regeneration of ME explants in 2,4-D. A comparison of ME and ImE responses indicated that ImEs are the best explants for high plantlet regeneration in durum wheat. Ourfindingssuggestthatpicloramisthebestauxin and should be used instead of 2,4-D due to its positive effect on increasing plant regeneration of durum wheat ME and ImE explants.