1Department of Production Engineering and Plant Genetics, Faculty of Science and Agricultural Engineering, Razi University, Kermanshah, Iran
2Department of Agricultural Biotechnology, Tarbiat Modares University, Tehran. Iran
3Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute, AEOI, Karaj, Iran
Callus induction from the leaf explants of Withania coagulans was assessed using the MS culture media containing co-application of BAP (0.1, 0.3, and 0.5 mg/L) and 2,4-D (0.1, 0.3, and 0.5 mg/L) based on a completely randomized design (CRD) with three replicates. Furthermore, the potential interaction effects of three different tissues (hypocotyl, stem, and leaf) of W. coagulans and two different Agrobacterium rhizogenes strains (R1000 and GM) were scrutinized for the hairy root induction using a factorial experiment based on CRD. For callus induction, among nine different hormonal treatments resulted from multiplying three concentrations of BAP and three concentrations of 2,4-D, one of which (i.e., “0.1 mg/L 2,4-D + 0.5 mg/L BAP”) had the maximum amounts of fresh weight (3.024 g), dry weight (0.082 g), and callus volume (16.91 cm3), as it was significantly different from the remaining eight hormonal treatments for the three traits (Duncan's test, p < 0.05). To make clear discrimination among nine different hormonal treatments and determine the best one(s) for callus induction in W. coagulans, a hierarchical cluster analysis (HCA) was also applied. All the treatments were placed in three main groups of I (six members), II (one member), and III (two members), of which the second cluster containing only one member (i.e., the hormonal treatment of “0.1 mg/L 2,4-D + 0.5 mg/L BAP”) had the highest quantities of the three aforesaid traits, could be accordingly proposed towards acquiring higher biomass. Regarding hairy root induction, no significant differences were observed either for interaction or for single effects (p < 0.05). However, among six different combinations (two strains and three tissue), the hairy root induction ratios ranged from 38.33% (GM/Hypocotyl) to 59.23% (for R1000/Leaf). Therefore, applying R1000 strain and leaf explant seems to be more effective for hairy root induction in W. coagulans compared to the other five combinations.