before plastic house for about 30 days before field transplanting. Before transplanting, seedlings were screened for resistance to one or more diseases, either by MAS or by greenhouse inoculation. Resistant Intensive selection for tomato yellow leaf curl disease and late blight resistance was practiced during the F1–F4 generations. Tomato yellow leaf curl disease in southern Taiwan is caused by Tomato yellow leaf curl Thailand virus (TYLCTHV) and Tomato leaf curl Taiwan virus (ToLCTWV) (Tsai et al., 2011) with the highest pressure occurring from March to June and coinciding with high white fly populations. Plants with tomato yellow leaf curl disease resistance genes identified by MAS were assessed in the field for tomato yellow leaf curl disease severity. Late blight screening relied on seedling inoculation with selected pathogen isolated.