Characterization of Early Blight Resistance in a Recombinant Inbred Line Population of Tomato: I. Heritability and Trait Correlations

Most commercial cultivars of tomato (Solanum lycopersicum) are susceptible to early blight (EB), a devastating fungal (Alternaria solani and A. tomatophila) disease of tomato in the US and elsewhere. Common measures of disease control currently include sanitation, crop rotation and heavy use of fungicides. Use of resistant cultivars, however, is the most economically acceptable and environmentally sound approach to controlling EB disease in tomato. Sources of genetic resistance to EB have been identified within the related wild species of tomato, including S. habrochaites, S. peruvianum and S. pimpinellifolium. Characterization of genetic resistance to EB would facilitate transfer of resistance to elite breeding lines and hybrid cultivars of tomato. We used a recombinant inbred line (RIL) population of tomato, previously developed from a cross between S. pimpinellifolium accession LA 2093 and S. lycopersicum tomato breeding line NCEBR-1, to determine the inheritance of EB resistance as well as