A Comparative Study Between Grafting and Mechanical Inoculation Mediated Transmission of Tomato Yellow Leaf Curl Virus in Tomato (Solanum lycopersicon) Cultivars Grown in Ghana

Global tomato production is seriously limited by the Tomato Yellow Leaf Curl Virus (TYLCV), leading to food insecurity globally. We studied the responses of six tomato cultivars to mechanical inoculation and grafting modes of TYLCV transmission in Ghana. Post mechanical inoculation and grafting mediated transmission resulted in upward leaf curl, stunted growth, and reduction in plant height, suggesting a successful transmission by both methods. However, disease symptom severity varied depending on the tomato cultivar as well as the mode of transmission. Transmission via grafting was more efficient in disease transfer, resulting in higher disease severity compared to those infected via mechanical inoculation. The presence of TYLCV decreased plant height and internode length regardless of the mode of transmission. TYLCV significantly decreased chlorophyll content over the controls but increased proline content than the controls. Correlation analysis revealed both positive and negative relationships between the methods of TYLCV transmission and the morphological traits of the plants studied. A strong positive correlation was observed in chlorophyll content by grafting, while plant height positively correlated with mechanical inoculation (r = 0.973). We conclude that the grafting mode of transmission is more effective than mechanical inoculation and could be used to study the propagation of phloem-limited TYLCV viruses in epidemiological studies for effective management.