Protocol Optimization and Evaluation of Soybean (Glycine max L.) Varieties for In vitro Regeneration Response

The most vital and ancient seed legume is the soybean (Glycine max L. Merril), contributing significantly to global protein concentrate used in animal feed and edible oil production. In the present study, an efficient and improved plant regeneration protocol was developed for soybean. Various explants, viz., apical meristem, shoot tip, and nodal segment, were collected from in vitro germinated seedlings of six commercially cultivated varieties- Phule Durva (KDS-992), Phule Kimaya (KDS-753), Phule Sangam (KDS-726), JS-335, DS-228 and JS-9305. Seeds were surface sterilized with Tween-20 for 20 minutes, Bavistin (1%) + Streptocycline (0.5%) for 20 minutes, HgCl2 (0.1%) for 45 seconds, NaOCl (1%) for 60 seconds, and ethanol (70%) for 30 seconds, then soaked overnight in autoclaved double-distilled water. Before inoculation, seeds were pretreated with BAP (1%) solution for two seconds for better germination. Treated seeds inoculated on MS + 1 mg/l BAP and B5 media revealed maximum germination (95%), with Phule Durva (95%) and Phule Kimaya (90%) performing best. Shoot induction from different explants was evaluated, with nodal segments showing optimal shoot development in MS + 2.0 mg/l BAP + 0.3 mg/l GA3 media. Phule Kimaya and Phule Durva showed higher shoot induction rates. Profuse rooting was obtained in ½MS + 2.0 mg/l IBA + 0.1 g/l charcoal nutrient media, with Phule Sangam and Phule Kimaya performing better. For primary hardening, coco peat:sand (1:1), and for secondary hardening, soil : organic mixture (1:1) marked maximum survival. The optimized protocol helps in successful transgenic production and gene editing.