2012 Annual Report 1a.Objectives (from AD-416): Develop iceberg, romaine, and leaf lettuce cultivars with resistance to bolting, tipburn, powdery mildew, big vein and extended shelf-life. 1b.Approach (from AD-416): Field, greenhouse, laboratory, and molecular marker experiments to develop and select lettuce lines with improved performance for fall, winter, and spring planting slots in Arizona. 3.Progress Report: The agreement was established in support of Objective 1 of the in-house project, the goal being to breed crisphead and mixed lettuce with resistance to pests and physiological defects common in Arizona. Five field experiments were conducted to evaluate and select breeding lines and families for resistance to premature bolting, Fusarium wilt, big-vein disease, and the physiological defect tipburn. More than 300 families and breeding lines were evaluated, and 87 plants from 16 superior families were selected for additional breeding.