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

Abstract

ABSTRACT The tomato (Solanum lycopersicum L.) is one of the most important vegetables from an economic, social, and nutritional point of view, being widely consumed throughout the world, both fresh and processed. Due to its importance, this crop is a constant focus of genetic improvement programs that seek to develop superior genotypes, such as higher quality, yield, and disease resistance. Thus, the aim of this study was to select experimental indeterminate Italian tomato hybrids with high yield, superior fruit quality, and resistance to TSWV (tomato spotted wilt virus) via molecular markers. The trial was conducted in the municipality of Ijaci, southern Minas Gerais, Brazil. A randomized 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 resistance to TSWV under natural infection and through molecular markers to identify the Sw5 gene. Six experimental hybrids stood out in terms of high yield, with hybrid TO-014 being superior to the others, presenting better size and higher commercial classification. Most genotypes showed few defects, revealing good qualitative characteristics, with the exception of three hybrids (TO-004, TO-042, and TO-134), which demonstrated greater susceptibility to TSWV. Seven experimental hybrids were considered resistant to TSWV because they carry the Sw-5 gene and did not show symptoms of infection in the field. Six of these hybrids also stood out in terms of yield and fruit quality, demonstrating that resistance to the virus has a direct impact on productive characteristics.