Developing optimal postharvest handling portocols for cut Polianthes tuberosa L. single spikes

Abstract

The cut flower industry of Pakistan is at its initial stages of development and growers are producing cut flowers only in open field. Tuberose is heat loving plant and can successfully be grown with little care, which makes it the only choice for the cut flower growers during summer season in Punjab, Pakistan. More often local florist markets become glutted with it during peak production time, which results in heavy postharvest losses and price drop, causing economic losses to the tuberose stakeholders, viz. growers, wholesalers and retailers. At present no valid data base is available regarding the postharvest handling practices being followed by the local tuberose stakeholders. Keeping in view popularity of tuberose among local growers and high market demand in local flower markets, present study was initiated to develop a valid database for postharvest handling protocols by the tuberose stakeholders. Study was completed in two phases, in first phase a survey of tuberose stakeholders was conducted. Survey results demonstrated that all postharvest handling practices currently used by the stakeholders were not as per recommended international standards. Therefore, in the second phase, a series of postharvest experiments were performed to find out best suited postharvest handling practices for cut tuberose spikes, viz., optimal harvest stage, pulsing, packaging materials, storage method and durations, water quality and vase preservative solutions. The study concluded that the best stage for harvesting spikes was when lower buds are fully mature and have expanded but yet not opened. Among various pulsing treatments, 10% sucrose plus 50 mg L-1 salicylic acid for 24 hours proved best for extending vase life. Storage of spikes in water (wet) proved best for storage of spikes up to six days at 4±2 0C. Likewise cut spikes wrapped in polythene sleeves alone or packed in floral boxes lined with polythene stored at 4±2 0C up to 3 days had longest vase life and better quality and this storage period can be extended up to 6 days in dark without any significant loss of quality. Spikes kept in carbonated plus distilled water (1:1) performed best followed by distilled, deionizes and reverse osmosis water for various spike and floret characteristics. Vase solution containing 2% sucrose plus 50 mg L-1 salicylic acid had the longest postharvest longevity and maintained quality of cut tuberose spikes. In summary, vase life of cut tuberose spikes can be considerably extended by following proper postharvest handling protocols.