Regulated root zone water temperatures and soilless media improve bulb yield and offset production of hydroponically cultivated Amaryllis belladonna L.

Abstract

The protracted natural bulb growth rate and offset generation constrain the timely expansion of bulbs in Amaryllis belladonna. An 18-month experiment was conducted to determine the efficacy of different root zone water temperatures and soilless media on the bulb yield and offset production of A. belladonna cultivated in a deep water culture hydroponic system. The study comprised dormant juvenile bulbs that were planted in plastic cavity trays filled with soilless media and suspended in heated water reservoirs at different temperatures (16 °C control, 22 °C, 28 °C, and 34 °C). The results found that the autonomous analysis of water temperatures, as opposed to soilless media and the combination, was significant. Warm root zone water temperatures ranging from 16 °C to 28 °C resulted in comparable aerial and subsurface morphological growth and development, promoting the vegetative proliferation of larger juvenile mother bulbs and offset induction. However, an excessively high temperature of 34 °C proved injurious and depleting. The results infer that the intrinsic processes for ‘bulbing’ were synchronized under inducive extrinsic hydroponic stimuli. A water temperature of 22 °C is recommended for long-term, sustainable production of simultaneously generating optimum reclaimable bulbs and offset generation to abridge the timeous cultivation of continuous A. belladonna vegetative bulb stock. A water temperature of 22 °C is recommended for long-term, sustainable production of simultaneously generating optimum bulbs and offset generation to abridge the timeous cultivation of continuous A. belladonna vegetative bulb stock.