Correlation analysis between the flowering of edible flowers and greenhouse environmental factors in southern Thailand
Chattamas Promdach1, Panupon Hongpakdee2, Ladawan Lerslerwong1
1Prince of Songkla University, Agricultural Innovation and Management Division (Plant Science), Thailand
Growing edible flowers in Southern Thailand is limited by excessive precipitation and high humidity. Therefore, the production of edible flowers as potted plants under greenhouse conditions and essential information on the effects of environmental factors is required. Eight selected species of edible flowers were Impatiens (Impatiens wallerana), two of Dianthus (Dianthus chinensis), ‘Diamond Series’ and ‘Diana Series’, Pansy (Viola tricolour), Snapdragon (Antirrhinum majus), Celosia (Celosia spicata), Cosmos (Cosmos sulphureus), and Torenia (Torenia fournieri). Seedlings were grown as potted plants under a 7.5 m × 30 m greenhouse at PSU Smart Farm, Klong Hoi Khong Research Station, the Faculty of Natural Resources, Prince of Songkla University, Thailand. Environmental factors, including maximum, minimum, and average temperature, relative humidity, light intensity, and daylength, were recorded using a data logger. The results based on the flowering date after transplanting, it could be divided into four groups as follows: 1) Celosia and Cosmos (early, <50 days), 2) Antirrhinum, Impatiens, and Torenia (moderate, >50-60 days), 3) ‘Diana Series’ and ‘Diamond Series’ Dianthus (relatively slow, >60-70 days), and 4) Pansy (slowly, >70 days). Correlation analysis between flowering and environmental factors, including temperature, relative humidity, length intensity, and daylength were performed using Pearson’s Correlation Coefficient method. A significant positive correlation was found very high (r = 0.91-1.00) between daylength and all flower species. Light intensity and maximum temperature exhibited high positive (r = 0.81-0.90) and very high positive effects on flowering, depending on the flower species. The interpreted results, especially photoperiod, light intensity, and maximum temperature, will apply to manage suitable environmental factors to control flowering for commercial-scale production in the humid tropical region.
Keywords: Daylength, light intensity, ornamental plants, Pearson’s Correlation Coefficient, temperature
Contact Address: Ladawan Lerslerwong, Prince of Songkla University, Agricultural Innovation and Management Division (Plant Science), 90110 Hat Yai, Thailand, e-mail: ladawan.lpsu.ac.th