Salt-Tolerant Crop Research May Offer Drought Help

Salt-Tolerant Crop Research May Offer Drought Help “Water scarcity and soil salinity are among the greatest challenges facing agriculture today,” says Devinder Sandhu, a research geneticist at the U.S. Salinity Laboratory, USDA-ARS. “Recurring droughts, declining snowpack, and increasing competition for freshwater are forcing growers to rely more on lower-quality irrigation water, including saline groundwater and recycled water. At the same time, millions of acres of farmland worldwide are affected by salt accumulation, which reduces crop productivity and farm profitability.” This reality makes the work of the U.S. Department of Agriculture’s Agricultural Research Service scientists especially urgent. Sandhu believes that if farming is to remain productive in water-limited regions, crops must become part of the solution. His research focuses on developing crop varieties that maintain high yields under saline conditions. “Salt-tolerant crops will allow farmers to make productive use of marginal lands and alternative water sources, helping conserve high-quality freshwater for crops that are more sensitive to salinity,” he explains. “Ultimately, this research will improve the sustainability and resilience of agriculture while supporting food and forage production in water-limited regions.” Sandhu’s approach blends traditional plant breeding with modern molecular genetics. The scope is broad, as researchers screen thousands of genetically diverse plant lines in greenhouses, growth chambers, outdoor lysimeters, and field trials. They identify lines that naturally perform well under salt stress and then study the physiological responses, genes and biological pathways behind the performance. Promising plants are crossed to combine complementary tolerance traits, and their offspring are tested over several generations under increasingly saline conditions. “Over the past decade, we’ve investigated salinity tolerance of 20 plant species, including cereal crops such as wheat, oat, barley, quinoa and maize; legume crops such as alfalfa, beans and guar; vegetable crops including spinach, tomato, pepper and eggplant; and fruit and nut crops such as almonds, avocados, passion fruit, strawberries and grapes. The knowledge gained not only helps improve each crop but also provides insights that can be transferred across breeding programs to accelerate the development of more resilient varieties,” Sandhu says. Practical progress is already notable. In alfalfa, researchers have developed an experimental breeding line with exceptional salinity tolerance through repeated selection, capable of surviving salinity levels approaching seawater. In almonds, a range of commercial rootstocks has been screened, and promising candidates are now in advanced evaluation for California orchards. The work also reaches deep into plant biology. Key salinity-tolerance genes from Prunus, spinach and alfalfa have been identified and functionally validated by introducing them into Arabidopsis mutants, confirming their role in helping plants withstand salt stress. This knowledge gives breeders more precise tools and shortens the path from discovery to field-ready varieties. “One of the most encouraging outcomes of our research is that we’ve shown there’s tremendous untapped genetic variation for salinity tolerance within crop plants,” Sandhu says. “In the future, I expect this research to result in improved crop varieties, rootstocks and breeding tools that’ll help growers make better use of salt-affected soils and lower-quality irrigation water.” Sandhu continues, “The broader impact will be greater flexibility in where and how crops are grown, reduced pressure on high-quality freshwater supplies, and more reliable production in regions where salinity is already a major agricultural challenge.” Contact: FARM SHOW Followup, Devinder Sandhu, U.S. Salinity Laboratory, USDA-ARS, Riverside, Calif. 92507 (devinder.sandhu@usda.gov).

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