The use of resistance genes in crop breeding is one of the most efficient approaches to mitigating viral diseases. To determine whether commercial hybrid tomato cultivars contain the Sw-5b gene and/or confer TSWV resistance and applied the Sw-5b-specific molecular markers for the gene detection. The Sw-5b gene is a gene in tomatoes that confers resistance to the Tomato spotted wilt virus (TSWV). Using specific molecular markers to detect the presence of Sw-5b in commercial tomato cultivars can be valuable for breeders, growers, and researchers. Here are some potential applications:

  1. Marker-Assisted Breeding: Molecular markers can be used in marker-assisted breeding programs to select plants with the Sw-5b gene. This accelerates the breeding process by allowing breeders to identify and select plants with the desired traits more efficiently. It helps in developing tomato cultivars with enhanced resistance to TSWV.
  2. Quality Control in Seed Production: Seed companies can use molecular markers as a quality control measure to ensure that the seeds of commercial tomato cultivars carry the Sw-5b gene. This ensures that the resistance trait is maintained in successive generations of plants.
  3. Disease Management: Growers can use molecular markers for early detection of the Sw-5b gene in their tomato plants. This information can guide them in implementing appropriate disease management strategies. If the gene is present, the plants are likely to have resistance to TSWV, reducing the need for extensive pesticide applications.
  4. Research and Development: Researchers studying plant-pathogen interactions or working on improving resistance mechanisms can use these molecular markers to identify and study the Sw-5b gene in different tomato cultivars. This aids in understanding the genetic basis of resistance and may contribute to future advancements in plant breeding.
  5. Commercial Production Planning: Knowledge of the presence or absence of the Sw-5b gene in commercial cultivars can influence production planning. Growers and producers can make informed decisions on planting strategies, especially in areas where TSWV is a significant threat. Additionally, the deployment of marker-assisted techniques requires collaboration between researchers, breeders, and the agricultural industry to ensure effective integration into practical applications.

Dr. Md. Monirul Islam
Senior Scientist

Fig. Breeding TSWV-resistant tomato lines with the assistance of Sw-5b-specific molecular markers. a Flow chart illustrating the cultivation of Sw-5bR homozygote Micro-Tom lines. b Phenotypes and genotypes of the plants obtained in each round of the breeding process of Sw-5bR homozygous Micro-Tom lines. In each round, plant phenotypes were observed, and the genotypes were determined using the Sw-5b-specific molecular markers.