A Hydroponic Approach to Evaluate Salt Tolerance in Cotton



Journal Title

Journal ISSN

Volume Title



Interests in developing salt tolerant cultivars have intensified as the result of an increasing population and environmental constraints that limit crop productivity. New agronomic models have been designed to address the new challenges. Some include the development of a salt tolerant crop by evaluation and selection of tolerant germplasm, hybridization with selected germplasm, and development of inbred lines through pedigree selection or backcross, and testing of selected inbred lines. Many wild accessions in cotton have been found in many areas in the world and made accessible for research. Plant breeders are trying to produce new cotton varieties that can withstand the excessive salt concentrations found in the soil and in the water since salinity has become a limiting factor in crop agriculture. For farmers the abiotic stress due to salinity limits yield by inhibiting germination, flowering, and the development of vegetative branches and fruiting branches. Other concerns of plant breeders are abscission of cotton bolls, a reduction in cellulose deposition, and that both photosynthesis and stoma conductance are affected during the breakdown and conversion into carbohydrates.

Preliminary studies conducted in 2006, 2007, 2008, and 2009 show one wild accession, TX 307 to be significantly more tolerant than others when plants were treated with NaCl. Since 2010, the focus of this research has been to use the hydroponic system as a screening method to evaluate and compare responses among cotton genotypes for salt tolerance characteristics to salinity stress. The wild cotton accession TX 307 was used as a control line to compare to three commercial cultivars ‘FM 989’ (PI603956, PVP9800259), ‘DP 491’ (PI618609, PVP 200100159, US2003/0229928AI), and ‘Coker 312’ (PI529278, PVP7200100); and two transgenic lines Avp68 and Avp86. Coker 312 was the cultivar used for the transformation and regeneration of Avp68 and Avp86 transgenic lines. Responses were evaluated at different salt concentrations (dose response) and at the same concentrations over time. The study was conducted under greenhouse conditions at the AgriLife Research and Extension Center in Lubbock, Texas. Experimental design was a randomized split block with four replications, four treatments, and ten plants/treatment sampling error.

Significant differences (p < 0.05) were found during the dose response screening study, however, no significant response genotype interactions over time was observed. The hydroponic system was perhaps not the best method for evaluating response differences at later plant development stages because of possible premature plant death, but it was an effective screening method to isolate individual plants with respect to morphological and physiological responses to salinity stress. The system could also be used as an assessment tool to identify contrasting phenotypes at high salt concentrations early in plant development.