Location: Application Technology Research
Project Number: 5082-21000-001-076-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2023
End Date: Aug 31, 2028
Objective:
The primary objective is to improve the postharvest performance of important crops grown by the U.S. floriculture industry. We will specifically focus on young plant production, working to improve the survival of unrooted cuttings in propagation following airfreight shipment. Non-optimal conditions during air freight shipment result in plant damage, physiological disorders, and delayed rooting. These problems affect crop scheduling and add labor and production costs. Our approach will be to explore technologies and techniques that can improve the shipping environment, enhance cutting longevity, reduce disease incidence and enhance cutting recovery following shipment prior to stick in propagation. Initially, we will explore four ideas that have the potential to meet our research objectives. Then, the most promising concepts will be pursued in more depth in future years. Thus, this first year will explore three ideas with the goal of identifying the best candidates for future years.
Approach:
Initially, we will explore three broad ideas that have the potential to meet our research objectives. Then, the most promising concepts will be pursued in more depth in future years. Thus, the first year will explore three ideas with the goal of identifying the best candidates for future years.
Cutting storage: Hypobaric storage can be used to store unrooted cuttings over multiple weeks. Additionally, LED lighting at very low light intensities can extend storage duration. We will test both hypobaric storage and LED lighting during storage individually and in combination.
Temperature management during shipping: We will conduct simulated shipping scenarios in growth chambers to evaluate the potential added value of using phase-change materials that increase the melting point of water such that shipping boxes can maintain the typical target temperature of 10 °C.
Post-shipping cutting recovery and performance enhancement: The time of sticking cuttings provides an opportunity to simultaneously treat the cuttings with multiple products via dip applications. Following are five groups of products that have the potential to improve cutting performance in propagation following shipment.
Adjuvants for hydration. Cuttings often wilt between the time of unpacking and being placed on the propagation bench. Providing adjuvant solutions immediately prior to sticking can rapidly hydrate the cuttings. We will test commonly available adjuvants to identify rates and times of exposure that can increase cutting turgidity without causing phytotoxicity.
Carbohydrates to replenish and maintain tissues. Carbohydrate application before sticking or to the propagation substrate provides an opportunity to rapidly bring carbohydrate levels back up to normal tissue concentrations. We will apply sucrose in pre-stick dip applications as well as to the propagation substrate at the time of sticking. The sucrose will need to be flushed from the substrate to reduce bacterial and fungal growth and photosynthesis should return the tissues to normal carbohydrate levels by day 5 after sticking.
Hormones for rooting. Our approach is to apply rooting hormones as a pre-stick whole cutting dip. This application has been used for that last several years by a few progressive growers, but it has not been fully developed. Our approach will be to screen a range of species to identify optimal application rates and time of exposure.
Anti-senescence hormones. Gibberellic acid and cytokinins have been used in propagation for many years to reduce leaf yellowing of geraniums. This technique will be tested on other species that are prone to experience lower leaf yellowing, e.g., mandevilla, euphorbia hybrids, catharanthus etc.
Biorational products for botrytis management. Botrytis is the primary pathogen that limits the postharvest longevity of floriculture crops, e.g., cuttings in vertical indoor propagation systems. The use of biorational products for botrytis management are yielding promising results, so these will be tested for their efficacy when applied at the time of sticking.
