MSc Thesis
Despite the potential of improved sweet potato (Ipomoea batatas L.) varieties in both root
and fodder production, farmers are persistently cultivating local types without considering
proper intensity and frequency of leaf removal to optimize both quality and quantity of
roots. A study was carried out to determine growth responses of improved sweet potato
varieties (Simama, Kiegea and Mataya) following leaf harvests; determine the effect of
leaf harvest intensity on sweet potato root and leaf yields; and, evaluate the effect of
harvest interval on leaf and root yields. Treatments consisted of four harvest regimes;
harvest intervals (4, 6 and 8 weeks) and harvest intensities (10 - 70%). A split-plot
arangement in randomized complete block design (RCBD) with 3 replication was used.
Data collected included leaf dry matter, total dry matter, vine length and fresh weights of
leaves and vines, root yileds. The results showed that highest dry biomass yields were
recorded with 70 % harvest intensity at 4 weeks harvest interval. Among the varieties,
highest dry leaf yields were observed with Mataya variety at 134 DAP and 70 % harvest
intensity. Highest vine branches were observed with Mataya variety at 6 weeks harvest
interval and 50 % harvest intensity. Longer vine was observed at 4 and 8 weeks harvest
interval with 10 and 40 % harvest intensities, for varieties Simama and Mataya,
respectively. Highest root yields were observed with Mataya variety at 6 week harvest
interval with 10 % harvest intensities. Highest root cluster were recorded with 50 %
harvest intensity, at 8 weeks harvest interval. Largest root diameter were observed with
Mataya variety than varieties Kiegea and Simama. Longest root were observed with
Mataya variety at 4 weeks harvest interval and 50 % harvest intensity. The present study
has revealed that agronomic management of sweet potato crop should be chosen
depending on the desired produce. When given as the sole food and feed to farmer and
growing livestock, Mataya is better variety. If root production is desired, leaf harvesting
in Mataya variety should not exceeding 50 % with 8 weeks interval.
International Development Research Centre (IDRC