Vol. 6, Issue 2, Part C (2024)

The present study investigates the genetic basis of key agronomic and quality traits in Solanum lycopersicum var. cerasiforme (cherry tomato) through Quantitative Trait Loci (QTL) mapping using an F2 population. A cross between two distinct parental lines exhibiting variation in fruit size, color, and disease resistance was developed to identify QTLs associated with fruit weight, size, color, and resistance to Phytophthora infestans. Phenotypic evaluation and genotyping were performed using high-density SNP markers, and QTL analysis was conducted through Composite Interval Mapping (CIM). Significant QTLs were detected on chromosomes 2, 4, 7, and 9, collectively explaining over 75% of phenotypic variance across measured traits. The major QTL for fruit weight on chromosome 2 (PVE 28%) and fruit size on chromosome 4 (PVE 22%) correspond to loci previously linked with yield traits. A strong QTL for fruit color on chromosome 7 (PVE 35%) and a disease resistance QTL on chromosome 9 (PVE 30%) demonstrated stability across different environments, indicating their potential for use in marker-assisted breeding. Correlation analysis revealed a strong positive association between fruit weight and size (r = 0.85), and between fruit color and disease resistance (r = 0.72), suggesting genetic linkage and pleiotropic effects. Marker-Assisted Selection (MAS) validation in F3 progeny confirmed the utility of the identified QTLs in improving multiple traits simultaneously. The integration of molecular markers with conventional breeding approaches significantly enhances selection efficiency, enabling the development of high-yielding, disease-resistant, and superior-quality cherry tomato cultivars suitable for diverse growing conditions.