Verticillium Wilt — Tomato (Interspecific Hybrids)

The disease is caused by the imperfect fungi Verticillium dahliae and, less frequently, Verticillium albo-atrum. For tomato, the division of the pathogen into race 1 and race 2 is fundamental, where resistance to the former is controlled by the Ve locus, which includes the Ve1 and Ve2 genes. When utilizing the wild species Solanum habrochaites in breeding, researchers often search for additional quantitative trait loci (QTLs) that provide broader protection than the classic Ve1 gene.

The first symptoms appear during the flowering or vegetative stage as unilateral yellowing of the lower leaves, followed by wilting that does not recover during nighttime hours. A diagnostic sign is the browning of vascular bundles in a cross-section of the stem; however, unlike Fusarium wilt, necrosis rarely extends more than 30 centimeters above the soil surface. In breeding materials, the presence of resistance is often denoted by the codes V or Vd.