Among the diseases that occur in the watermelon (Citrullus lanatus), a disease caused by Watermelon mosaic virus (WMV) is considered of great importance. Considering that genetic resistance is the best method for controlling virus diseases, it is important to know the genetic inheritance for each virus resistance. Aiming to study the inheritance of resistance to WMV in watermelon, crosses were made between Crimson Sweet (CS) and the resistant line L26. Segregants and non-segregants plant populations were inoculated with an isolate of WMV. The inoculated plants were evaluated by indirect ELISA with antiserum for WMV and symptomatology in the inoculated plants, according to a previously established graded scale. The hypothesis of monogenic inheritance was tested under different presumed average degrees of dominance as well as using the maximum likelihood. The estimated variances of the populations were used to obtain the genetic (σ2G), the environmental (σ2E), phenotypic (σ2F2), additive (σ2A) and dominance (σ2D) variances as well as the broad (h²a) and narrow sense (h²r) heritabilities. The monogenic inheritance was rejected. The estimation of the average degree of dominance indicated complete dominance. The broad sense heritability was low for the two variables analyzed. Therefore, the genetic control of resistance to WMV in the watermelon populations analyzed showed to be oligogenic, with the presence of additive and non additive effects as well as the presence of major genes and polygenes.
Citrullus lanatus; genetic control; WMV
