Taro corm quality in response to planting date and post-harvest storage: I. Starch content and reducing sugars

Abstract

The effect of four planting dates (October, November, December and January) and three fertilizer application rates (0, 160 and 320 kg ha-1 of nitrogen) on starch and reducing sugar content was investigated for three taro landraces (Dumbe-dumbe, MgingqeniandPitshi) from KwaZulu-Natal, South Africa, which were produced at two sites, Ukulinga and Umbumbulu. The effect of two storage temperatures (12°C and ambient temperature: 21°C ±3) and three packaging methods (polyethylene bags, mesh bags and open cardboard boxes) on starch and reducing sugars following storage was determined. At Ukulinga, delaying planting significantly decreased starch content, whereas at Umbumbulu starch content was significantly decreased by application of fertilizer. Reducing sugars were decreased by delayed planting when no fertilizer was applied, but increased when high N amount was applied at Ukulinga. Fertilisation had no effect on reducing sugars of Dumbe-dumbe but increased reducing sugars of Mgingqeni. For Pitshi, reducing sugars were increased when high N fertilizer was applied. At Umbumbulu, delaying planting generally increased reducing sugars for Dumbe-dumbe andPitshi and decreased reducing sugars for Mgingqeni. Ambient temperature and mesh bag storage showed the best combination for taro cormel storage. Key words: Landrace, nitrogen, organic fertilizer, packaging material, site, storage temperature.