Wednesday, November 7, 2007
258-9

Comparison of Three Methods to Screen Soybean Genotypes for Salt Tolerance.

Jeong Dong Lee1, Scotty Smothers1, David Dunn1, Margarita Villagarcia2, Thomas Carter2, and J. Grover Shannon1. (1) University of Missouri-Delta Center, 147 State Highway T, P O Box 160, Portageville, MO 63873, (2) USDA-ARS, North Carolina State University, 3127 Ligon St., Raleigh, NC 27607

Soybean cultivars with salt tolerance are needed to prevent yield losses in fields where excess salt is a problem. Soybean genotypes have been evaluated for salt tolerance in the greenhouse using primarily a labor intensive and costly hydroponic method. Two simple, inexpensive methods were compared to the hydroponic method to evaluate soybean genotypes to salt. Four to six single plants of 14 soybean genotypes including checks- Hutcheson(salt sensitive)and S100 (salt tolerant) were grown and exposed to 100mM salt solution at the V2-V3 growth stage 1) in 20 cell plastic inserts filled with sandy soil and placed within plastic flats to hold salt solution (Flat method); 2)in plastic cone-tainers filled with sandy soil placed in racks and placed in sterlite containers to hold salt solution (Cone-tainer method) and 3)in plastic containers filled with vermiculite placed in racks and partially submerged in nutrient solution which was changed every three days after initial planting with salt solution added at the proper time (Hydroponic method). The Cone-tainer method was the most comparable to the Hydroponic method in detecting tolerant and sensitive genotypes. Correlation coefficients for leaf scorch ratings in relation to the Hydroponic method were 0.96 and 0.69 for Cone-tainer and Flat methods, respectively. Leaf chloride content was greater and leaf scorch ratings could be made about one week sooner (five weeks versus six weeks after planting) in the Flat and Cone-tainer methods versus the Hydroponic method. Exposure of roots at V2-V3 growth stage to salt solution using the Cone-tainer method gave similar results, was much less labor intensive, and more cost effective compared to the Hydroponic method to screen soybean genotypes for salt tolerance. ________________________________________