Flower Bud Development and Growth Characteristics of Four <i>Allium</i> species Native to Korea in Response to Photoperiods

Abstract

To crossbreed wild Allium species with imported Allium and obtain new varieties, it is necessary to understand the flowering physiology of Allium species Native to Korea. In this study, we examined the flowering response of four Allium species to photoperiod adjustments. We started the experiment on June 28 using plants with four leaves and one inflorescence. To determine the photoperiodic response, the plants were subjected to long-day (16 h, LD), short-day (9 h, SD), or open field conditions. LD and SD conditions were conducted in a controlled environment with a Phyto-Garden System maintained at 25°C, 70% humidity, and 296 ± 13 μmol･m-2 ･s-1 light intensity. Day extension (DE) treatment was conducted with additional time with 5 μmol･m-2 ･s-1 fluorescent light intensity. The growth parameters (plant height, plant width, leaf length, leaf width, and number of leaves) and flowering characteristics (number of inflorescence and number of days to flowering) were assessed. Under SD condition, the plant height, plant width, leaf length, and leaf width of A. taquetii were higher than those under LD and open field conditions. Among the four Allium species, A. taquetii was the most grown under SD condition after bolting. Under SD condition, the first flower of A. longistylum, A. thunbergii var. teretifolium, A. linearifolium, and A. taquetii bloomed after 51.8 days, 46.5 days, 43.7 days, and 52 days, respectively. Under LD condition, not all species had complete flowering at the end of the experiment. Under open field conditions, the flowers of four A. species bloomed after 97.2 days on average. These results indicate that the four Allium species have an obligate flowering response to photoperiod.