In-ground post maturity storability of five local sweetpotato varieties

Abstract

Two experiments are described in which prolonged post maturity storability of sweetpotato (lpomoea batatas L.) was studied between 1990 and 1992 at Namulonge Agricultural and Animal Production Research Institute (NAARI). Five commonly grown local varieties Tanzania (TZ), Tororo I (TOR l), Tororo 3 (TOR 3), Kawogo (KA} and Kyebandula (KY) were harvested at 4, 5, 6, 7, 8, 9 and 10 months after planting (MAP). The harvest date (HD) for optimum storage root yieldsfor for varieties TZ, TOR I, KA and TOR 3 were at 8 MAP while that for KY was 9 MAP. Varieties KA and KY attained their optimum fresh root yield at 10 MAP while varieties TOR 3, TOH I and TZ attained theirs at 7, 8 and 8 MAP, respectively. Storage root quality varied among varieties and deteriorated with time for all varieties. The magnitude of weevil damage increased with increase in in-ground storage period, but remained relatively stable after 9 MAP. The different varieties correlated differently but not significantly with the level of weevil damage except TZ ( r= -0.88*). The dry matter content percent (DMC %) varied among varieties and was negatively but non significantly correlated with rainfall. In-ground post maturity period had no significant effect on root cooking quality, taste and texture. However, the optimum HD is crucial if optimum economic yield is to be achieved.