Abstract :
Continuous desertification of arable lands mandates use of low quality/saline water for irrigation, especially in the regions experiencing water shortage. Using low quality/saline water for irrigation imposes more stress on plants which are already under stress in these regions. Thus, a logical solution could be finding salt/drought tolerant plant species to survive/sustain under such stressful conditions. Since the native plants are already growing under such conditions and are adapted to these stresses, they are the most suitable candidates for use under these harsh arid environmental conditions. If stress tolerant species/genotypes of these native plants are identified, there would be a substantial savings in inputs (i.e., water, fertilizers, and agrichemicals) in using them under these stressful conditions. My research studies at the University of Arizona on various native grasses indicated that saltgrass (Distichlis spicata) has a great potential to be used under harsh environmental desert conditions and combat desertification processes. The objectives of this review article were to introduce saltgrass, a halophytic plant species, that through my investigations in various salinity and drought tolerant halophytic plant species has proven to be the most tolerant plant species for recommendation as the potential species for use under arid regions and areas with saline soils and limited water supplies or drought conditions for sustainable agriculture and combating desertification. In my various investigations, different saltgrass clones/accessions/genotypes were studied in a greenhouse to evaluate their growth responses under salinity or drought stress conditions. Grasses were grown vegetatively either hydroponically in culture solution for salt tolerance or in galvanized cans contained fritted clay for drought tolerance. For the salt tolerance, grasses were grown under 4 treatments [EC=6 (control), 20, 34, and 48 dSm-1 salinity stress] with 3 replications in a RCB design experiment. During this period, shoots were clipped bi-weekly for fresh and dry matter (DM) weight determination. At the last harvest, roots were also harvested and DM weights determined. For the drought tolerance, the growth responses of the grasses were evaluated under progressive drought condition for 4 months in a split plot design experiment with 3 replications. Shoots were harvested bi-weekly for DM determination. Although growth responses reduced at high salinity levels or as drought period progressed, all the grasses showed a high degree of salinity/drought tolerance. However, there was a wide range of variations observed in salinity/drought tolerance among the various clones/accessions/genotypes. The superior salinity/drought tolerant plants were identified which could be recommended for sustainable production under arid regions and combating desertification.
