Annual ryegrass has little tolerance to high salinity in soils or irrigation water. A plant breeding program is underway to increase salt tolerance of breeding populations of annual ryegrass. Both a greenhouse and a field screening method are being utilized in this effort. A preliminary laboratory screening in Petri dishes indicated that about 5% of our turf breeding populations germinated when seed were moistened with a salt solution concentration of 18,200 ppm (EC = 29.1 dS/m-1). Seed germinating and surviving at this level for 2 weeks were transplanted into a 50:50 sand/potting mix, into conetainers (4 cm x 20 cm). Trays of conetainers were submerged to near soil surface in a salt solution EC = 5.6 dS/m-1 and gradually raised to 38.4 and lowered to 24.0 dS/m-1. Nutrients were added as needed. The salt solution was aerated constantly, and changed weekly to reduce any algae growth. Plants were subjected to the high salt concentration for 54 days when the test was terminated. From the original 200 plants, 75 were selected as salt tolerant. The selected plants were transplanted into soil in larger pots, allowed to cross-pollinate and produce seed. The field screening took place on the TAES Experiment Station at Pecos, Texas. Approximately 5000 seed of a diverse population, were planted in soil with an EC = 1.4 dS/m-1 into an 8 by 20 m block. The block was irrigated 4 times during the season with irrigation water EC = 4.7 dS/m-1 salt. Approximately 60% of plants showing salt damage were eliminated with Roundup on May 3, 2005. The remaining plants were allowed to cross-pollinate and produce seed. Seed from each population will be increased and tested for improved salt tolerance.
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