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Because of restrictions imposed by crossing barriers, crested wheatgrass breeders have usually limited themselves to selection and hybridization within ploidy levels i.e., diploid (Zn=14), tetraploid (2n=28), or hexaploid (2n=42) populations. Several procedures have now been devised and evaluated to transfer genetic traits among ploidy levels, and interploidy breeding appears to be a feasible approach in the crested wheatgrass complex. Plant scientists with the USDA-ARS at Utah State University have developed a superior breeding population by hybridizing induced tetraploid Agropyron cristatum (L.) Gaertn. with natural tetraploid A. desertorum (Fisch. ex Link) Schult. The cultivar 'Hycrest' was released from this germplasm base in 1984. Chromosome number of the Hycrest breeding population ranged from 2n=28 to 32 and averaged 30. Chromosome pairing relationships were similar to those observed in natural tetraploids and the cultivar was as fertile as the parental species. Hycrest produced significantly more seeds per spike than 'Nordan,' and ample genetic variability for seed set existed in the population to make additional improvement through selection. Hycrest produced significantly (p

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Livestock losses from NO,, poisoning vary among locations. An understanding of the effect of environmental factors on NO,, accumulation in meadow plants may aid in management of meadowlands to reduce these losses. Controlled studies were undertaken to determine the effect of soil moisture, temperature, irradiance, and soil fertility on the yield and NO,, concentrations in herbage tissue of slender sedge (Carex praegracilis W. Boott), beardless wildrye (Elymus triticoides Buckl.), Nevada bluegrass (Poa nevadensis Vasey ex Scribn.) and reed canarygrass (Phalaris arundinacea L.). Reed canarygrass consistently yielded higher and contained higher concentrations of NO:, than the other species. Herbage yields were higher in all plants grown for 45 days at 30°C than in those grown for 45 days at 15°C. Yields were also higher in plants grown with 42.0 W/m' than they were in plants grown with 4.2 W/m?. Concentrations of NO,, were highest when plants were grown in unsaturated soil, with 4.2 W/m2, and they increased with fertilization. The NO,, concentrations obtained could be toxic to cattle (lethal NO,,-N level = 0.21%), especially when the plants were grown at 30°C in dry soils. When meadow plants were grown in saturated soil, the NO,, concentrations were never high enough to be toxic, even when the plants were heavily fertilized. I hc author i\ ;1 range scientist. Crops Research Laboratory. Scwnce and Education Admlnlwatwn. U.S. Department of Agriculture. Logan. Utah X4322. The report involv~scooprrativc investigation by the Scicnccand Education Administratlon. L'.S. Dep. qgr.. and the Oregon Agricultural Experiment Station. Oregon State C'nt\cr\lty. rechntcal paper no. 4x21 of the latter. The research was conducted by the author at the Squaw Butte Experiment Station. Burns. Oregon. Manuscript received July 20. 1978.