Effect of Variety and Harvesting Interval on Yield and Postharvest Quality of Frafra Potato (Solenostemon rotundifolius Poir)

Abstract

Frafra potato (Solenostemon rotundifolius Poir.) is a relatively underutilized root crop in Ghana. The crop is cultivated by smallholder farmers on less than 0.25 ha mainly in the Upper East and West Regions. Among the production constraints include the use of farmer-saved seed, low yield, high postharvest losses and little value addition technologies. This study assessed the yield, nutrient, sensory and shelf-life characteristics of 3 Frafra potato varieties and determined the optimum harvest maturity to maximize tuber yield.  Three varieties (Maa-lana, Naachem-tiir, and Nutsugah piesa) and 5 harvest intervals (80, 90, 100, 110 and 120 days after planting) were assessed in relation to yield and shelf-life characteristics. Overall, tuber yield was comparable among the varieties, but Maa-lana (2.74 t/ha) recorded higher yield compared to Naachem-Tiir (2.54 t/ha) and Nutsugah piesa (2.43 t/ha). Naachem-tiir had a favorable sensory score for ease of peeling (3.7) compared to Nutsugah piesa (3.6) and Maa-lana (3.4) as well as a higher overall acceptability score of 4.4 for Naachem-tiir compared to 3.6 for Nutsugah piesa and 2.4 for Maa-lana.  Simulating harvesting from 80 to 120 days provided reasonable tuber yield 1.12 (t/ha) - 3.22 (t/ha), with harvest interval of 100 days resulting in higher tuber yield. Optimizing storage at 6–8°C recorded decay losses of 5.7 to 6.8% and physiological weight loss of 4.6 to 5.7% during 16 weeks in storage. This study suggests utilizing vegetative propagules to increase seed security, and for scaling, Maa-lana and Naachem-tiir exude potential for higher productivity. The tuber yield of 1.12 t/ha recorded at the 80-day interval suggests that vegetative propagules can be used from late July to early August to obtain a reasonable yield, particularly when prolonged dry spells occur in early July.