Marker-assisted selection (MAS) for tomato spotted wilt virus (TSWV) resistance in Italian tomato genotypes

The aim of this study was to select experimental hybrids of indeterminate Italian tomatoes with high yield, superior fruit quality, and resistance to tomato spotted wilt virus (TSWV) through marker-assisted selection. The experiment was conducted in the municipality of Ijaci, located in the southern region of Minas Gerais, Brazil. A randomized complete block design was used, with 16 hybrids (12 experimental and 4 commercial controls), four replications, and five plants per plot. Evaluations were carried out for yield, fruit quality, and epidemiological aspects of TSWV incidence under natural infection conditions in the open field. The detection and characterization of genes associated with resistance to TSWV were also performed using molecular markers. Eight experimental hybrids stood out in terms of fruit yield, with hybrid TO-014 standing out for its productivity and for producing fruits with higher commercial classification. Most genotypes demonstrated few defects, revealing good qualitative characteristics, with the exception of three hybrids (TO-004, TO-042, and TO-034), which showed greater susceptibility to spotting caused by TSWV, confirming their susceptibility to tomato spotted wilt virus. Seven experimental hybrids were considered resistant to TSWV for carrying the Sw-5 gene and showing no symptoms of infection in the field. Six of these hybrids also stood out in terms of yield and fruit quality, highlighting that resistance to the virus has a direct impact on productive traits.