Micropropagation is an advantageous technique for commercial Lilium propagation. The aim of this work was to evaluate the impact of genotype, traumatic acid [TA, 10(E) dodeca-1,12-dicarboxylic acid] treatment and an initial bulb quality on lily in vitro propagation. Genotypes were: L. longiflorum Thunb. `Snow Queen', L. lancifolium Thunb., one Oriental hybrid (L. × `Stargazer'), and four Asiatic hybrids (L. × `Enchantment', L. × `Connecticut King', L. × `Sunray', L. × `Cote d'Azur'). Assays were done with good-quality bulb genotypes—chosen by water content, sprouting degree, and appearance—with exception of L. × `Cote d'Azur', where poor-quality bulbs were also included. Surface-sterilized 3-mm scale bulb sections where cultured in MS medium with 100 mg·l–1myo-inositol, 0.4 mg·l–1 thiamine·HCl, 0.1 mg·l–1 NAA, and 3% sucrose and 0.8% agar, pH 5.7. Cultures were kept in darkness at 25°C during 8 weeks. One μM TA was used to immerse half of the explants during 1 hr before culturing. Genotypes showed a wide variability in bulblets' number (1.7–2.9 bulblets per explant) and biomass (55–147 mg per bulblet). The same variability was observed after TA treatment, which produced an increase in bulblets number per explant (14% to 59%) and also a significantly augmented their fresh mass (9% to 42%). Poor-quality L. × `Cote d'Azur' bulbs adversely affected both biomass and number of bulblets produced on the scale sections, which was not overcome with TA treatment. These results suggest the convenience of TA application in Lilium micropropagation protocols on good-quality bulbs, irrespective to the genotype source.
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