Salt-Tolerant Crops: Time to Deliver.

Despite the numerous advances made in our understanding of the physiology and molecular genetics of salinity tolerance, there have been relatively few applications of these to improve the salt tolerance of crops. The most significant advances have historically utilized intraspecific variation, introgression of traits from close crop wild relatives, or, less frequently, introgression from more distant relatives. Advanced lines often fail due to difficulties in the introgression or tracking of traits or due to yield penalties associated with the alleles in nonsaline environments. However, the greatest limitation is that salinity is not a primary trait for breeders. We must close the gap between research and delivery, especially for farmers who have precious few alternatives. These efforts should include a reassessment of old techniques such as grafting current crops with salt-tolerant hybrid rootstocks. Alternatively, future crops can be produced via domestication of salt-tolerant wild species-an approach that is now feasible in our lifetime.