Standardization of tissue culture protocols for mass multiplication of gerbera varieties

Abstract:

Gerbera (Gerbera jamesonii Bolus) accounts for nearly 8 per cent of the global cut-flower trade, yet the supply of true-to-type planting material in Brazil meets barely 45 per cent of annual commercial demand. This research aimed to fix that gap by standardising a reproducible in-vitro protocol for five gerbera varieties of commercial value in the Minas Gerais highlands. Capitulum explants of Sciella, Doni, Tharani, Ruby Red and Silvester were surface-sterilised in 0.1 per cent mercuric chloride for eight minutes, then cultured on MS basal medium supplemented with six combinations of BAP, NAA, Kinetin, IAA and 2,4-D. Five experiments were conducted between September 2021 and March 2023 at the Plant Tissue Culture Laboratory of the Federal University of Lavras, Lavras. The best callus induction (87.3%) was recorded in Sciella on MS + BAP 3.0 + NAA 0.2 mg L⁻¹, which also gave the highest mean shoot number per explant (9.7) after six weeks of subculture. For rooting, half-strength MS supplemented with 0.5 mg L⁻¹ IBA induced an average of 6.8 roots per plantlet within 21 days, with rooting percentages ranging between 78 and 94 across varieties. Survival rate during ex-vitro hardening on sand: soil: FYM (1:1:1) reached 82 per cent after 40 days in the polyhouse. Genetic fidelity tests on ten RAPD primers confirmed that 94 per cent of regenerants were true-to-type. The standardised protocol can multiply a single explant into about 4,800 plantlets in nine months, supporting commercial nurseries across the Minas Gerais region.