Genetic analysis of resistance to early blight disease in tomato
Early blight is a fungal pathogen that causes destructive necrotic and chlorotic symptoms on leaves, stems and fruits of tomato plants. Host resistance remains the most desirable control strategy against the early blight disease. In this study, the responses of 6 cultivated and 3 wild tomato accessions were tested with 3 isolates of the fungal pathogen. To investigate inheritance of the resistance, resistant plants of NCEBR2 and NCEBR4 genotypes were crossed with susceptible NC84173 tomato line, and their F1, F2 and BC1 populations were established. In the established populations, resistance differences were significant (P>0.05) for NCEBR2 × NC8413 and NC84173 × NCEBR4 parents, F1 and BC1. However, no significance (P>0.05) was obtained in their F2 population to early blight pathogen. The data from these populations revealed that early blight resistance in NCEBR2 and NCEBR4 was quantitatively controlled by more than one gene or quantitative trait locus under controlled glasshouse environment.
Key words: Tomato, early blight disease, genetic analysis.