Tomato genotypes resistant to tomato spotted wilt virus evaluated in open field crops in Southern Italy.

摘要

Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) are the main viruses responsible for severe losses in open field tomato crops in Southern Italy. Control of TSWV is possible using resistant tomato genotypes carrying the Sw-5 resistance gene. The present work evaluated the incidence of viral damage and the yield of eighteen processing tomato genotypes resistant to TSWV (nine for peeling and nine for tomato concentrate), growing in open fields in the Sele Valley (Southern Italy) during summer 2004. Susceptible controls consisted of four tomato cultivars (two for peeling and two for tomato concentrate). At harvesting, the incidence of viral damage on fruits of tomato genotypes resistant to TSWV ranged from 3% to 34.3% for peeling tomato and from 0.7% to 23.7% for concentrate tomato, whereas the incidence of viral damage on the fruits of susceptible genotypes ranged from 27.7% to 37.6%. The yield of all resistant peeling tomato genotypes were statistically not significantly different from the susceptible cultivar Genius, but were lower than the susceptible cultivar Galeon. The yield of resistant tomato genotypes for concentrate was statistically not different from the susceptible cultivars. TSWV infections and those caused by other viruses were assessed by ELISA and checked in bulk leaf samples collected a few days before harvest. TSWV was detected in only one out of eighteen resistant genotypes. At least ten tomato genotypes (five for peeling and five for concentrate), resistant to TSWV, had shown a good response for lowest fruit damage as well as for satisfactory production. Finally, ELISA assays showed that all the tomato genotypes except one were resistant to TSWV populations spreading naturally in Southern Italy.