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United States Department of Agriculture

Agricultural Research Service

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Research Project: Salt-tolerant Lettuce and Spinach Varieties

Location: Crop Improvement and Protection Research

Project Number: 2038-21530-001-13-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2013
End Date: Jun 30, 2016

Salinity is a major constraint to lettuce and spinach production in California. The saltwater intrusion has continued to move farther inland because of continuing overdraft conditions for municipal and agricultural uses in the coastal regions. In Central Valley, salts accumulate in the field due to irrigation water from the Sacramento-San Joaquin Delta contaminated by seawater intrusion, a shallow water table, and a lack of adequate drainage outlet. The Imperial Valley is a desert region with less than three inches of rain annually and leafy green growers have to rely on salty Colorado River water for irrigation. Global warming also promotes water transpiration from plants and evaporation from soil, leaving more salt behind 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 study the inheritance of the trait. If only partial tolerance is found, these plants will be crossed to each other to increase the tolerance level. If the tolerance exists only in wild species, backcrosses will be used to transfer the trait into cultivars. 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.

Last Modified: 05/23/2017
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