2018 ASHS Annual Conference

Photoperiod is flowering inductive for many species, along with other influential parameters. Cultivated gladiolus, Gladiolus xgrandiflorus, a geophytic species producing corms, is known to be a long day plant. New seed-propagated gladiolus hybrids have been developed although the interaction and influence of photoperiod on asexual propagules (cormel, corm production) is unknown and poorly understood in commercial hybrids. In this research our objective was to study the influence of photoperiod on flowering and foliage height, number of leaves, and asexual propagule production (corm weight, number of cormels and weight). Clonal replications of three new seed-propagated gladioli breeding lines of the University of Minnesota and ‘Galmini’, a commercial cultivar comparison, were tested in both long and short day treatments. Short days inhibited flower bud initiation and development, but also significantly reduced foliage height, the number of leaves, corm weight, number of cormels and weight by treatment and genotype. The short day treatment negatively influenced gladiolus overall performance in growth and development.