Occurrence of cucumber mosaic virus within tomato seed lots

Abstract

Tomato (Solanum lycopersicum L.) is an important crop whose fruit is widely consumed globally. However, its yield is affected by cucumber mosaic virus (CMV) and can cause total crop failure. The virus is mainly transmitted by aphid vectors, but data on its spread via seeds are limited. Thus, the occurrence of CMV within tomato seed lots obtained from different sources was investigated. Seven tomato accessions and varieties were collected from five sources and evaluated for seed transmission of CMV. One hundred seeds each were sown in a plastic tray, and germination rates were recorded. The incidence and severity of virus symptoms were observed at 3, 6, and 9 weeks after sowing (WAS), while leaves were tested for CMV using antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA). The germination percentage ranged from 60% in accession 'V4' to 92% in 'UC-82B'. Infection rates were 100%, 71.74%, 70.31%, 45.90%, and 8.33% in 'Roma-VF', 'UC-82B', 'NG/AA/SQ/09/053', 'V2', and 'V4', respectively. 'Kerewa' and 'Alausa-Long' exhibited zero infection rates and tested negative for CMV using ACP-ELISA. Eighty percent of test plants became symptomatic at 6 and 9 WAS, although accession 'NG/AA/SQ/09/053' tested positive for CMV despite showing no symptoms. Tomato seeds from commercial stores, research institutes, and farmers' fields tested positive for CMV, while seeds from the market were negative at 9 WAS. The results from this study confirm the transmissibility of CMV through seeds in tomatoes, although the rate of seed transmission is cultivar dependent.