ASHS 2025 Conference

A greenhouse culture system simulated in-ground curing by imposing pre-harvest water deprivation treatments in sweetpotato. Virus-tested sweetpotato cv ‘Beauregard’ cuttings were planted at the following staggered times relative to the control (0d): 10 days (10d) and five days (5d) earlier, respectively. Water deprivation treatments were applied 10d and 5d pre-harvest. The first study terminated experiments when the control plants attained 30 days of growth. Storage root sections 1-2 mm thick were obtained from the broadest part of the storage root, stained with phloroglucinol, followed by image capture with a microscope. Digital image analysis was performed by measuring the area of the continuous lignified zone (CLZ) below the phellogen layer and calculating % CLZ after measuring the total area of the cross-section. Simulated WD at 10d and 5d was associated with a six- and three-fold increase in % CLZ, respectively. None of the control SRs showed 100% CLZ, while 50% of SRs subjected to 10d WD showed an intact ring of lignified tissue below the phellogen layer. Storage roots from control plants consistently showed breaks in the phellem tissue relative to SRs subjected to WD treatments. In the second study, plants were grown for up to 50 days, and harvested SRs were kept in ambient conditions for weight loss measurements. Water deprivation was associated with reduced weight loss in SRs relative to SRs grown in well-watered conditions. These findings can lead to follow-up work to validate increased skin durability with pre-harvest, in-ground curing in production areas where postharvest curing facilities aren’t available.