Search

Grass tetany or hypomagnesemic tetany in cattle (Bos taurus) is caused by an imbalance of K, Ca, and Mg in the diet. Indications of grass tetany range from reduced milk yield or weight gain to severe convulsions and death. The risk of grass tetany dramatically increases when the K/(Mg + Ca) ratio of forage exceeds 2.2, especially for dams during early lactation. Russian wildrye [Psathyrostachys juncea (Fisch.) Nevski], a valuable forage species, has ratios well above this level. Our objectives were to determine the mineral concentration and ratio values for 65 accessions of Russian wildrye to select germplasm sources with low tetany ratio and to determine the effects of year, location, and their interactions with accessions. Seedlings of each accession and two checks, Syn A and Mankota, were established in replicated space-plant nurseries at Logan, UT, Mandan, ND, and Swift Current, Saskatchewan, Canada. Years-within-location effects generally produced the largest variance component, while the accession variance was larger than location x accession and location x accession x year interaction variances for K, Ca, Mg, K/(Mg + Ca) ratio, and Reduced Tetany Potential (RTP) index. Selection for these traits in Russian wildrye germplasm will require multiple years to characterize adequately accessions, breeding lines, or synthetics. The lCd(Ca + Mg) ratio of the accessions tested ranged from 2.2 to 3.0 when averaged across sites and years for V4 growth stage. A similar range of ratio values and ranking of the accessions was observed at the E2 growth stage. The three tetraploid accessions evaluated were among the five accessions with the highest tetany ratios. Previously reported forage yield and seed yield means were significantly correlated with K, Mg, and N concentrations and K/(Ca + Mg) ratio. The RTP index was not correlated with forage yield, seed yield, or N concentration. Therefore, selection in Russian wildrye should be based on increased RTP index rather than K concentration or K/(Ca + Mg) ratio to avoid concomitant unintentional selection of reduced forage yield and seed yield., RUSSIAN WILDRYE GRASS is a valuable cool-season, ceaspitose forage species of the Northern Great Plains and Intermountain regions of North America (Rogler and Schaaf, 1963). It has higher forage quality, [...]

Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] accessions in the U.S. National Plant Germplasm System have not been adequately characterized for agronomic and morphological traits. Such characterization would be helpful in development of improved cultivars. Objectives of this study were to (i) measure consistency of dry-matter and seed yields as well as plant height and vigor of 65 Russian wildrye accessions and four cultivars at three diverse test sites, (ii) characterize phenotypic diversity among these accessions using cluster analysis, and (iii) define needs for future evaluation and collection of Russian wildrye germplasm. Field tests were conducted at Logan, UT; Mandan, ND; and Swift Current, Saskatchewan, Canada. Dry-matter and seed yields were not consistent among accessions and cultivars at the three locations, and testing at each location was necessary to identify accessions that were best suited to a specific location. Variance component estimates were small and of little consequence for accession x year interaction effects. The 69 entries were grouped into 10 clusters based on multivariate analysis of 17 classification variables. Accessions in Cluster 3 averaged well above the overall test mean for dry-matter yield, seed yield, and plant vigor and have high utility in plant breeding programs in North America. Only four accessions had high levels of resistance to Septoria spraguei Uecker & J.M. Krupinsky, an important foliar disease. Accessions from a defined geographic area tended to cluster, but some accessions from a particular area were spread among several clusters. This emphasizes the value of sampling diverse collection sites within a defined geographic area., RUSSIAN WILDRYE is a drought-resistant, cool-season, perennial bunchgrass that was introduced through official channels to the USA from central Asia in 1927 (Rogler and Schaaf, 1963). Reports of Russian wildrye [...]

`RoadCrest' crested wheatgrass [Agropyron cristatum (L.) Gaertn.] (Reg. no. CV-25, PI 606546), a rhizomatous cultivar, was developed by a research team at the USDA-ARS Forage and Range Research Laboratory, Utah [...]

Several putative hybrids between Elymus elymoides (Rafin.) Sweezey and Leymus salinus (M.E. Jones) A. Love subsp, salmonis (C. Hitchc.) Atkins were found growing on the west side of the Great Salt Lake, near Lakeside, UT in 1995. Naturally occurring hybrids between these two species have not been documented previously. Cytological, morphological, and chloroplast DNA analysis of the hybrids and parents confirmed the hypothesis that these plants were hybrids of the two species. Elymus elymoides and L. salinus subsp, salmonis were the only Triticeae species growing in the area that could have contributed to the intermediate morphological features expressed in the hybrids. Leymus salinus subsp, salmonis (NsNsXmXm; 2n = 4x = 28) and E. elymoides (StStHH; 2n = 4x = 28) are allotetraploids that regularly formed 14 bivalents at metaphase I (MI). The hybrids between the two species are also tetraploids and averaged 22.1 univalents and 2.86 bivalent associations per cell at MI. Chromosome pairing in the hybrids suggests essentially no homology between the chromosomes from the two parents; thus the genomic formula for the hybrid can be written as StHNsXm. The hybrids were morphologically intermediate between the suspected parent species, but they resembled L. salinus subsp, salmonis more closely than E. elymoides. Analysis of chloroplast DNA in the hybrid and its putative parents, demonstrates cytoplasmic DNA identical to E. elymoides, suggesting that E. elymoides was the maternal parent. Complete sterility and reduction in chromosome pairing in the natural hybrids between E. elymoides and L. salinus subsp, salmonis suggest that the potential for genetic exchange between the two species is limited or lacking. Due to hybrid sterility, the natural hybrid will have little impact on the native vegetation of the western deserts of Utah and, without restored fertility, has no potential as a restoration grass on semiarid range sites., NATURAL HYBRIDS between members of the grass tribe Triticeae (wild relatives to wheat) have been frequently reported in plant communities where several species live sympatrically (Stebbins et al., 1946; Dewey [...]