Optimizing Harvest Time for Sweet Potato in the Kurdistan Region of Iraq

Sweet potato [Ipomoea batatas (L.) Lam.] is considered a multipurpose plant with numerous applications and health benefits due to its high nutritional antioxidant, rich in fiber, and vitamins A and C. This study was conducted to determine the optimal harvesting time for sweet potato (Jewel Yams variety) cultivated for the first time in the Kurdistan Region of Iraq (KRI). The study was conducted in a RCBD (randomized block design), with five treatments which were harvested in different interval times (70, 90, 110, 130, and 150 days), 7 plants per plot, and 3 replications. After each interval of harvesting, the total yield, individual weight, size, and number of sweet potatoes per plot, as well as sweet potato quality attributes such as sugar content, were assessed using a digital refractometer (ATAGO 3810 PAL-1). The results showed that harvesting time significantly (P ≤ 0.05) affected the yield performance of the sweet potatoes. The highest values of tuber weight (265.81 g/plant), average length (36.55 cm), width (36.35 mm), sugar content (6.34%), and total weight per plot (2.79 kg) were recorded in plots harvested 150 days (150 HD). While number of fruits per plant reached a maximum (4.86) in samples harvested after 130 days. In addition, the trends of increasing the total yield per plot compared to the earliest harvest (70 days) are as follows: 349%, 843%, 871%, and 2495% for 90, 110, 130, and 150 days, respectively. It can be concluded that harvesting times have considerable potential for enhancing sweet potato traits in terms of yield and quality. Consequently, this study suggest that farmers may base decisions upon the ultimate tuber size, degree of sweetness, and overall yield per unit area, harvesting at 130–150 days after planting, depending on the tuber maximum or quantity of interest. It is, therefore, concluded that the practice of sweet potato harvest for marketing purposes must be prolonged to 150 days for the KRI to achieve high market quality and profitability.