Abstract
In order to understand the genetic basis of Pierce's Disease (PD) resistance, a segregating population with 184 F[sub1] progeny of N18-6 × 'Cabernet Sauvignon' was investigated in the experimental vineyard at Florida AM University, Tallahassee, Fla. The population evaluated was used to identify gene(s) responsible for host resistance to Xylella fastidiosa, the causative agent of PD. A field evaluation was conducted utilizing 0 to 5 scales for severity of PD symptoms, where 0 = no PD symptoms, 5 = the most severe PD symptoms. A total of six evaluations were made in the summer and fall, 2002 and one in spring of 2003. Individual progenies started to show symptoms in late August, with severity ranging from 0-3. More seedlings developed PD symptoms in September, with majority of them showing PD symptoms ranging from 1 to 3, with the exception of two plants that showed 4 and 5. PD seemed to progress through late fall/early winter for some hybrids as evidenced by the increase of PD infected vines (91%). Some severely infected seedlings did not recover in the following spring. The resulting population is being used to tag and map the genes responsible for PD.
