Growth and proliferation in vitro of Vaccinium corymbosum under different irradiance and radiation spectral composition

Plantlets of highbush blueberry (Vaccinium corymbosum) cvs. Atlantic, Barkeley and Elizabeth, were exposed in vitro to radiation of different spectral compositions obtained by filtering the cool-white light. Red colour of leaves was the first response to the light treatments. On average, cv. Atlantic yielded the highest number of shoots per explant (10.4), followed by cv. Elizabeth (9.1) and Berkeley (6.5). No-B-PMMA increased the proliferation rate in all the 3 genotypes, especially in cv. Atlantic. Cutting wavelengths between 650 and 760 nm (no-R-PMMA filter) generally depressed the proliferation rate. No-B-PMMA induced remarkable changes in the morphology of the shoots - more elongate leaves and longer internodes - especially in cv. Atlantic