2012 Annual Report 1a.Objectives (from AD-416): To develop heat-tolerant lettuce and spinach germplasm that is adapted to global warming and low land cost areas of California. 1b.Approach (from AD-416): We will use germplasm screening and breeding to find and create heat-tolerant lettuce and spinach germplasm, and test them in spring and summer trials conducted in coastal, Central and Imperial Valleys of California. 3.Progress Report: This project contributes directly to the objectives 1 and 3 of the in-house project, genetic improvement of lettuce and spinach. This report documents research conducted under a cooperative agreement with California Department of Food and Agriculture. Global warming and climate change pose serious challenges to California agriculture and place unprecedented pressures on the sustainability of horticulture industry. Adapting the leafy greens industry to future conditions is essential to meet the need of growing population and increasing demand for leafy vegetable products. Seeds were placed in Petri dishes to test their ability to germinate at high temperature (34C) as compared to controls at 24C. Three week-old seedlings were exposed to heat stress (43/35C day/night) for a week before being assessed for leaf and plant damages as well as growth reduction. By using these methods we were able to identify different lettuce genotypes that can tolerate heat stress and/or germinate under high temperature conditions.