Yield evaluation of multiple and co-infections of begomoviruses and potyviruses on sweet potato varieties under field conditions and confirmation of multiple infection by NGS

• Published in: Crop protection 2019-05, Vol.119, p.102-112
• Main Authors: Mulabisana, M.J., Cloete, M., Laurie, S.M., Mphela, W., Maserumule, M.M., Nhlapo, T.F., Cochrane, N.M., Oelofse, D., Rey, M.E.C.
• Format: Article
• Language: English
• Subjects: Begomoviruses; Next-generation sequencing (NGS); Potyviruses; Single and co-infections of viruses; Total and marketable yield
• ISSN: 0261-2194; 1873-6904
• DOI: 10.1016/j.cropro.2019.01.009

Potyviruses and begomoviruses are regarded as the most common viruses affecting sweet potato production in South Africa (SA). The impact of single and mixed virus infections on the yield of sweet potato varieties have not been established in SA. The objective of this study was to determine the effects of potyviruses and begomoviruses on sweet potato total and marketable yield. Twelve varieties, 8 locally bred and four imported, were selected for evaluations and these were graft-infected with different virus combinations: 1) co-infections of the russet crack (RC) strain of Sweet potato feathery mottle virus (SPFMV) + Sweet potato virus G (SPVG) + Sweet potato virus C (SPVC) + begomoviruses [Sweet potato leaf curl Sao Paulo virus (SPLCSPV) + Sweet potato mosaic virus (SPMV)] [(treatment (T) 1)]; 2) co-infections of SPFMV (RC strain) + begomoviruses (T2); 3) single infection of the RC strain of SPFMV (T3); and 4) co-infection of the begomoviruses SPLCSPV and SPMV (T4). Next generation sequencing (NGS), reverse transcription polymerase chain reaction (RT-PCR) or PCR confirmed the identification of the viruses in sweet potato plants used as sources of various treatments. Two consecutive field trials were planted in January 2014 and 2015, respectively. Varieties produced significantly reduced total [(F11, 236 = 5.17); P