1a.Objectives (from AD-416):
To develop drought-tolerant lettuce and spinach germplasm that is adapted to global warming.
1b.Approach (from AD-416):
We will use germplasm screening and breeding to find and create drought-tolerant lettuce and spinach germplasm, and test them in spring and summer trials conducted in coastal, Central and Imperial Valleys of California.
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 Reimbursable Agreement between ARS and 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. Lettuce accessions of the U.S. germplasm collection are being screened in greenhouse under drought conditions together with normal control plants in a preliminary experiment. By using these methods we were able to identify different of lettuce genotypes that can tolerate drought stress. Candidates showing potential drought tolerance were selected through the analysis of multiple drought-stress parameters, including wilting, leaf relative water content, and fresh weight as compared to well-watered controls. We have identified 200 candidate varieties of lettuce that are being tested in field trials in the Salinas Valley. This initial screening of lettuce germplasm represents a substantial first step in developing cultivars improved for production in regions with increasing pressure on freshwater availability along with providing another tool by which producers and breeders can choose cultivars adapted for limited-water stress.