The Sw-5 locus confers dominant resistance to tomato spotted wilt virus (TSWV). To map the location and facilitate the identification of markers linked to Sw-5 we developed a pair of near-isogenic lines (NILs) and an F2 Lycopersicon esculentum x L. pennellii population segregating for resistance to TSWV. DNA from the NILs was analyzed using 748 random 10-mer oligonucleotides to discern linked molecular markers using a random amplified polymorphic DNA (RAPD) approach. One random primer (GAGCACGGGA) was found to produce a RAPD band of about 2200 bp that demonstrates linkage to Sw-5. Data from co-segregation of resistance and restriction fragment length polymorphisms (RFLPs) in a F2 interspecific population position Sw-5 between the markers CT71 and CT220 near the telomere of the long arm of chromosome 9.

No abstract

No abstract

Pepper mild mottle virus (PMMoV) has been identified on pepper in Florida several times since 1997. Initial observations were on ornamental peppers (Capsicum chinense, C. frutescens, and C. annuum). However, in the winter growing seasons of 1999 and 2000, PMMoV was detected in several bell pepper (C. annuum) cultivars in commercial production fields in south Florida. Symptoms in bell pepper plants were observed to vary with plant age and cultivar, and included stunting of young plants and puckering and yellow mottling of leaves. Fruit was deformed (lumpy and mottled) and slightly reduced in size. Older fruit exhibited brown streaks and, in some cultivars, an undesirable color at maturity. Incidence in commercial bell pepper fields varied from <1 to 30%. Symptoms on mechanically inoculated indicator hosts, analysis of viral-associated double-stranded RNA, and inclusion body morphology suggested the presence of a tobamovirus. PMMoV was specifically identified by serological testing using ELISA (Agdia, Elkhart, IN). To our knowledge, this is the first definitive identification of PMMoV (2) in Florida, although a prior isolation of the same or a similar virus was made in 1964 and reported as the Samsun latent strain of Tobacco mosaic virus (1). The occurrence of this seedborne virus in an area of intensive commercial pepper production requires careful monitoring to avoid future significant losses. References: (1) W. H. Greenleaf et al. Phytopathology 54:1367, 1964. (2) C. Wetter. Plant Dis. 68:597, 1984.