Explant position influences in vitro flowering of 'Little Pinkie' gentian

M. Keshavarzi, K.A. Funnell, D.J. Woolley, J.A. Heyes
When propagules of gentian 'Little Pinkie' were generated in vitro, each progressive subculture resulted in a reduction in the duration to flower production when deflasked plants were subsequently grown in vivo. The initiation of flowering in propagules while growing in vitro reduced the quality of potted plants produced, and reduced the overall efficiency of the micro propagation system by 40%. Hence determining factor(s) influencing the onset of flowering and developing strategies to maximise persistent vegetative growth of explants were considered to be important for commercialisation of this cultivar. The effect of position from which explants originated on flowering in vitro was investigated. A gradient of propensity for explants to flower was found to exist along the shoot from which explants were derived. Explants derived from the tip had the greatest propensity to flower (35%), and the percentage of flowering decreased with distance from the tip. Explants derived from the first node below the tip produced four times fewer flowering plants than those derived from the tip, while only 6% of explants flowered when derived from the second node. To optimise the efficiency of propagation of 'Little Pinkie' therefore, modifying the propagation protocol from mass propagation to selective propagation is suggested, wherein explants derived from the tip of original shoots are not recommended for inclusion. In contrast, lower nodes may be used as propagules for either subculture in vitro or production of potted plants.
Keshavarzi, M., Funnell, K.A., Woolley, D.J. and Heyes, J.A. 2016. Explant position influences in vitro flowering of 'Little Pinkie' gentian. Acta Hort. (ISHS) 1131:111-118
flower initiation, flowering time, in vitro culture, persistent vegetative, position

Acta Horticulturae