In vitro micropropagation of Basella rubra L. through proliferation of axillary shoots

Key message We established a novel, and efficient protocol for in vitro B. rubra shoot cultures further multiplication in MS basal medium without any plant growth regulators with 100% elongation and rooting of microshoots that will overcome the use of synthetic hormones for improved micropropagation. In vitro micropropagation protocol for Basella rubra regeneration was tried through proliferation of axillary shoots of the potted mature plant. The improved seed germination (70%) was recorded upon 2% urea treatment. The nodal shoot segments from matured potted plant were used to initiate the multiple shoot proliferation. The shoot segments exhibited 70% shoot initiation when cultured on Murashige and Skoog (MS) medium supplemented with Indole-3-acetic acid (IAA) + N-6 - Benzylaminopurine (BAP) (0.25 + 2.0 mg/L) and BAP + Kinetin (Kin) (2.0 + 0.5 mg/L) respectively. Multiple shoots (5-6) were obtained on MS medium supplemented with BAP + Kin and IAA + BAP respectively. When compared with silver nitrate (AgNO3) (2-40 mu M) and activated charcoal (AC) (0.1-1.0%), the MS medium devoid of any plant growth regulator showed good number of shoots (5.48 +/- 2.42), elongation (15.64 +/- 2.42 cm) and root length (14.52 +/- 2.78 cm). Upon transferring of regenerated microshoots to MS medium, simultaneous elongation of shoots with more shoot number, shoot length and rooting was achieved during four subcultures that carried out at 6 weeks' interval. The regenerated in vitro shoots showed 100% rooting in MS medium and also in MS medium supplemented with 0.1-1.0% AC. Hundred percent survival of micropropagated shoots well rooted was established successfully under greenhouse condition and the plants were subsequently acclimatized and transferred to the field conditions wherein 90% success rate was noted.

Automated summary

A novel and efficient in vitro micropropagation protocol was established for B. rubra shoot cultures without the use of plant growth regulators, achieving 100% elongation and rooting of microshoots. Seed germination was improved to 70% with urea treatment, and multiple shoot proliferation was initiated using nodal shoot segments from mature plants in pots. Multiple shoots were obtained with specific growth regulator combinations, and successful rooting was achieved in both MS medium and MS medium supplemented with activated charcoal.