Yield, nutritional quality and stability of orange-fleshed sweetpotato cultivars successively later harvesting periods in Mozambique

Abstract

Long-term storage of sweetpotato roots is a great challenge for smallholder farmers in Mozambique. Piecemeal harvesting allows several months supply of roots for household consumption provided weevil infestation is avoided. The objectives of the present studies were to determine yield and changes in key macro- and micronutrients associated with early or late harvesting of orange-fleshed sweetpotato cultivars in Mozambique. Four trials representing harvesting periods of 3, 4, 5 or 6 months after planting were established at Gurue in 2015. The randomized complete block design with three replications was laid in each trial. Yield measurements were done in the field and samples were selected and scanned for dry matter, beta-carotene, iron, zinc and carbohydrate using Near Infrared Spectrometry. Collected data were statistically analysed (SAS 1997 software). Yield, dry matter, starch, iron and beta-carotene increased linearly in some cultivars as time to harvest was prolonged. Iron was not affected by harvesting period. Stability of micronutrients such as iron, zinc and beta-carotene is essential when piecemeal harvesting. The study allowed accurate grouping of the cultivars tested into maturity groups for the first time.