Salt-Tolerant Lettuce and Spinach Varieties
Crop Improvement and Protection Research
Project Number: 2038-21220-005-17
General Cooperative Agreement
Start Date: Oct 01, 2013
End Date: Jun 30, 2016
Salinity is a major constraint to lettuce and spinach production in all major production areas in California. On the central coast, seawater has intruded into the ground water supplies due to continuing overdraft conditions. In the Central Valley, salts accumulate in the soil because of irrigation water from the Sacramento-San Joaquin Delta contaminated with brackish water from the San Francisco Bay, a shallow water table, and a lack of adequate drainage outlet. In the Imperial Valley, a desert region with less than three inches of rain annually, growers rely on the salty Colorado River water for irrigation. Global warming promotes water transpiration from plants and evaporation from soil, increasing salt accumulation in soil. We propose to screen and develop salt-tolerant lettuce and spinach germplasm and cultivars to adapt to the changing environment. Successful completion of the project will improve the profitability and sustainability of lettuce and spinach crops in California.
In the first year, we will screen our lettuce/spinach germplasm collections (the largest in the world) and lettuce mutant collection for salt-tolerance in greenhouse using salinized sand cultures. Tolerant lines will be tested again to confirm the results. Salt-tolerant varieties of different horticultural types will be evaluated in field trials under salt stress conditions delivered through the drip irrigation system in the second year. We will also start to characterize salt-tolerant traits and study the gene expression and inheritance of the traits. Best performing varieties from field trials will be evaluated in the field in Salinas, Central, and Imperial Valleys in the third year to demonstrate the results to the industry and seed companies, through which seeds of salt-tolerant cultivars will be made available to growers.