Sweetpotato is usually propagated in Uganda by vine cuttings from mature crops, but sometimes sprouts from storage roots are used, especially in drought-prone areas. No information is available on whether the storage of roots of Ugandan cultivars are infected with the viruses and whether the sprouts on them express symptoms so that farmers can eliminate diseased ones. Information on root sprout reversion from virus infection is also lacking. The storage roots of five sweetpotato cultivars was sourced either by random selection of roots from already harvested roots or obtained from symptomless plants selected before harvest at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK), and the National Semi Arid Resources Research Institute (NaSARRI). Roots were also generated in a screenhouse after being inoculated with Sweet potato feathery mottle virus (SPFMV) and/or Sweet potato chlorotic stunt virus (SPCSV). More than 70% of sprouts from roots of all the cultivars selected after harvest at MUARIK and NaSARRI were infected with the viruses. For roots obtained from symptomless plants, 64% and 21% of the sprouted roots from MUARIK and NaSARRI were infected with the viruses, respectively. Most of the root samples from MUARIK had visible virus symptoms on sprouts and tested positive for both SPFMV and SPCSV, whereas those from NaSARRI did not show symptoms and were infected primarily with SPFMV. Plants graft-inoculated with either SPCSV or SPFMV alone produced both infected and noninfected roots, whereas all the root sprouts from dually infected plants showed virus symptoms. Reversion from virus infection was observed on root sprouts infected singly with SPFMV, whereas those infected with SPCSV showed recovery only, and none of the root sprouts infected by both viruses showed recovery. This study proves that roots are good reservoirs for viruses, and reversion occurs only when singly infected with SPFMV. Therefore, there is a need to establish seed channels in which seedstock is cleaned continuously and made available to farmers.
This research was supported by the International Potato Center (CIP) through the Sweetpotato Action for Security and Health in Africa (SASHA) project as part of the Consultative Group for International Agricultural Research (CGIAR) Research Program on Roots, Tubers and Bananas (RTB).
ArituaV.El-BedeOwyE.LanyaM.O.EwelP.2000Yield and reaction of non-indigenous sweetpotato clones to sweetpotato virus disease in Uganda p. 48–54. In: Y. Nakazawa and K. Ishiguro (eds.). Proceedings of the 1st International Workshop on Sweetpotato Cultivar Decline Study 8–9 Sept. 2000. Miyazaki Miyakonojo Japan
BashaashaB.MwangaR.O.M.Ocitti p’ObwoyaC.EwellP.T.1995Sweet potato in the farming and food systems of Uganda: A farm survey report. International Potato Center (CIP) and National Agricultural Research Organization (NARO) Lima Peru
ClarkC.A.MoyerJ.W.1988Compendium of sweet potato diseases. The AmerPhytopathol. Soc.1293101
Clark,C.A.Moyer,J.W.1988Compendium of sweet potato diseases. The Amer1293101)| false
GibsonR.W.MwangaR.O.M.NamandaS.JeremiahS.C.BarkerI.2009Review of sweetpotato seed systems in East and Southern Africa. Integrated Crop Management Working Paper 2009-1/ International Potato Center (CIP) Lima Peru.
GibsonR.W.NamandaS.SindiK.2011Sweetpotato seed systems in East AfricaJ. Crop Improv.10449451
Gibson,R.W.Namanda,S.Sindi,K.2011Sweetpotato seed systems in East Africa10449451)| false
HallA.J.BockettG.N.NahdyS.1998Sweet potato post-harvest systems in Uganda: Strategies constraints and potentials. International Potato Centre (CIP) Social Science Department Working Paper Series No. 1998-7. CIP Lima Peru
KaryeijaR.F.GibsonR.W.ValkonenJ.P.T.1998The significance of sweetpotato feathery mottle virus in subsistence sweetpotato production in AfricaPlant Dis.82415
Karyeija,R.F.Gibson,R.W.Valkonen,J.P.T.1998The significance of sweetpotato feathery mottle virus in subsistence sweetpotato production in Africa82415)| false
MianoW.D.2008Replication of viruses responsible for sweet potato virus disease in resistant and susceptible sweetpotato genotypes and identification of molecular markers linked to resistance. Louisiana State University and Agricultural and Mechanical College PhD Diss
MilgramM.CohenJ.LoebensteinG.1996Effects of sweet potato feathery mottle virus and sweet potato sunken vein virus on sweet potato yields and rates of reinfection of virus-free planting material in IsraelPhytoparasitica24189193
Milgram,M.Cohen,J.Loebenstein,G.1996Effects of sweet potato feathery mottle virus and sweet potato sunken vein virus on sweet potato yields and rates of reinfection of virus-free planting material in Israel24189193)| false
NamandaS.2012Current and potential systems for maintaining sweetpotato planting material in areas with prolonged dry season: A biological social and economic frame work. University of Greenwich PhD Diss
NamandaS.GibsonR.SindiK.2011Sweetpotato seed systems in Uganda, Tanzania and RwandaJ. Sustain. Agr.358870884
Namanda,S.Gibson,R.Sindi,K.2011Sweetpotato seed systems in Uganda, Tanzania and Rwanda358870884)| false
NdunguruJ.KapingaR.SeruwagiP.SayiB.MwangaR.O.M.TumwegamireS.RugutuC.2009Assessing the sweetpotato virus disease and its associated vectors in northwestern Tanzania and central UgandaAfr. J. Agr. Res.4334343
Ndunguru,J.Kapinga,R.Seruwagi,P.Sayi,B.Mwanga,R.O.M.Tumwegamire,S.Rugutu,C.2009Assessing the sweetpotato virus disease and its associated vectors in northwestern Tanzania and central Uganda4334343)| false
WasswaP.2012Sweetpotato viruses in Uganda: Identification of a new virus a mild strain of an old virus and reversion. University of Greenwich PhD Diss
WasswaP.OttoB.MaruthiM.N.MukasaS.B.MongerW.GibsonR.W.2011First identification of a sweet potato begomovirus (sweepovirus) in Uganda: Characterization, detection and distributionPlant Pathol.6010301039
Wasswa,P.Otto,B.Maruthi,M.N.Mukasa,S.B.Monger,W.Gibson,R.W.2011First identification of a sweet potato begomovirus (sweepovirus) in Uganda: Characterization, detection and distribution6010301039)| false
YanggenD.NagujjaS.2006The use of orange fleshed sweetpotato to combat vitamin A deficiency in Uganda: A study of varietal preferences extension strategies and post-harvest utilization. Social Sciences Working Paper No. 2006-2. The International Potato Centre Lima Peru