2019 ASHS Annual Conference

Sweetpotato [Ipomoea batatas (L.) Lam.] is a tropical perennial native to the Americas and is suited for both large and small-scale, organic and conventional production. Sweetpotato is propagated vegetatively through stem cuttings known as slips. In the United States, slip production is concentrated in the Southeast and sweetpotato growers in regions such as Kansas are reliant plant material that is shipped from outside the region. Transportation and storage conditions can result in low quality slips that may perform poorly after being planted in the field. Little information regarding proper postharvest storage and handling practices for sweetpotato slips is available. Furthermore, shipping and packing practices vary among slip producers. The objectives of this study were to identify the optimal storage and shipping conditions related to temperature and packaging for sweetpotato slips and identify the threshold of slip quality that leads to poor field performance. Slips of ‘Orleans’ were harvested at the John C. Pair Horticultural Center (Haysville, Kansas, USA) and transported to the Postharvest Physiology Laboratory at Kansas State University Olathe (Olathe, Kansas, USA). Upon arrival the slips were cut to size and placed into small waxed cardboard boxes with or without nylon film liner. Boxes were stored in environmental chambers at three different temperatures: 16°C, 22°C, 30° at 65% relative humidity. An overall quality rating scale was developed, which rated slips from 1 to 1 9 (1- completely senesced to 9- field fresh slip). Quality was monitored throughout storage by measuring chlorophyll fluorescence, color, water loss, respiration, and chlorophyll content. A complementary field study was conducted to determine the performance of slips at quality ratings 9, 7, 5, 3, 1. Slips stored at 16°C had the longest storage life, maintaining marketable quality up to 10 days. Followed by 8 days for 22°C and 6 days for 30°C. After 4 days of storage samples stored without a liner exhibited higher average rates of water loss (11.5%). This difference was significant at all temperatures between liner and no-liner (16°C p=.0133, 22°C p=.0042, 30°C p=.0025.) The results of this work show that temperature and the addition of a liner play a critical role in maintaining quality and freshness of sweetpotato slips. Information from this study increases postharvest knowledge of sweetpotato slips with hopes to aid in creating new standardized shipping practices. Ultimately, leading to increased availability of quality planting material for sweetpotato producers in the Midwest