Cultivated tomato (Solanum lycopersicum) is susceptible to late blight, a major disease caused by the oomycete Phytophthora infestans. In our previous work, quantitative resistance to this pathogen from wild tomato Solanum habrochaites was mapped, two resistance QTLs (on chromosomes 5 and 11) were introgressed into cultivated tomato and confirmed with near-isogenic lines (NILs). These resistance QTLs were further refined via higher-resolution mapping using 120 recombinant sub-NILs that were also evaluated for horticultural traits. Using a phenotypic selection index, a set of sub-NILs was identified that exhibited resistance to P. infestans and horticultural traits similar to cultivated tomato. Subsequently, the selected sub-NILs were crossed with a set of commercial inbred lines in a North Carolina Design II mating design to generate F1 hybrids. These hybrids and their parents were tested for resistance to P. infestans in replicated field and growth chamber experiments and the combining ability of the sub-NILs was determined.