Simultaneous Shoot Proliferation, In Vitro Flowering and Rooting in Rose (Rosa hybrida L.)

Abstract

Conventional micropropagation of rose relies on separate phases for shoot multiplication, rooting and acclimatization, which increases production time, cost and operational complexity. In vitro flowering is rarely incorporated into propagation systems despite its value for breeding and physiological studies. This study aimed to establish a simplified integrated protocol enabling simultaneous shoot multiplication and in vitro flowering, followed by efficient rooting in Rosa hybrida. Nodal explants were cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP; 0–4.0 mg L⁻¹) and indole-3-acetic acid (IAA; 0–3.0 mg L⁻¹) under a completely randomized design (n = 15 per treatment). For rooting, regenerated shoots were transferred to full- or half-strength MS medium containing indole-3-butyric acid (IBA; 1.5 mg L⁻¹), with or without gibberellic acid (GA₃; 0.5 mg L⁻¹). Data were analyzed using ANOVA followed by LSD tests (p ≤ 0.05). The combination of MS + 3.0 mg L⁻¹ BAP + 3.0 mg L⁻¹ IAA produced the best morphogenic response, with early shoot initiation (18.22 days), highest shoot proliferation (3.60 shoots/explant) and maximum in vitro flowering (2.48 flowers/culture). Rooting was most efficient on full-strength MS medium supplemented with IBA, yielding 93.3% rooting with 4.67 roots per shoot and 2.60 cm mean root length. GA₃ application significantly reduced root elongation. The proposed system integrates shoot regeneration, flowering and rooting into a streamlined process, reducing culture handling and production time. This protocol may support accelerated rose breeding and in vitro floral research following further validation across cultivars.