Effect of leaf harvest and frequency on growth, yield and quality of sweet potato (Ipomoea batatas L.)

MSc ThesisDespite 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 (IDR