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‘Newell’ (Reg. No. CV‐275, PI 671851) smooth bromegrass (Bromus inermisLeyss.) is a steppe or southern type cultivar that is primarily adapted in the United States to areas north of 40° N and east of 100° W that have 500 mm or more annual precipitation or in areas that have similar climatic conditions because of elevation or latitude. It was developed to replace ‘Lincoln’, which is the most widely used smooth bromegrass cultivar in the region, by improving its forage digestibility. Newell bromegrass was developed by four generations of population improvement breeding for in vitro dry matter digestibility (IVDMD) and forage yield using Lincoln as the base population. In regional small plot trials, Newell produced forage with greater IVDMD than Lincoln and equivalent or greater forage yields. In a replicated grazing trial in eastern Nebraska, beef yearlings grazing Newell for a 3‐yr period produced significantly greater average daily gains and beef production per hectare than yearlings grazing Lincoln bromegrass.

Forage production from grasses grown in the semiarid northern Great Plains is primarily a function of available water during the growing season. There is a need to develop procedures using controlled environments to shorten the time for identifying germplasm that differs in water‐use efficiency (WUE). Field determination of WUE requires several years to evaluate genetic and environmental effects. This study compares WUE of field grown cultivars of crested wheatgrass [Agropyron desertorum(Fisch. ex Link) Shult.], intermediate wheatgrass [Thinopyrum interdium(Host) Barkworth and Dewey], and western wheatgrass [Pascopyrum smithiiRybd. (Löve)] to identical plants grown in a controlled environment. Net CO2assimilation (A), transpiration rate (E), A/E ratio, and conductances on a leaf basis for plants grown in a controlled environment were compared to WUE calculated from dry matter accumulation and total evapotranspiration for field grown plants. Generally, cultivars within a species that exhibited higher E and A and a lower A/E ratio in controlled environments also had higher field WUE. In contrast, comparisons among species indicated that crested wheatgrass had the lowest E, A, and A/E ratio, but had the highest field WUE. The intercellular C02concentration (C1) differed among cultivars within species, with the stomates of the higher WUE cultivars functioning to maintain higher c1. Correlations of field WUE with controlled environment measurements suggest that the A/E ratio is not a good predictor of field WUE for the species examined in this study.

Available water is a major factor limiting productivity of forage grasses grown in the northern Great Plains of the USA. Cultivars with greater water‐use efficiency (WUE) would be beneficial to forage production and utilization in this semiarid region. Our objective was to assess variability in forage yield and WUE among genotypes of four common forage grasses. Four clones with contrasting phenotypes were selected from each of three cultivars or strains of crested wheatgrass [Agropyron desertorum(Fisch. ex Link) Shult.], western wheatgrass [Pascopyrum smithiiRybd. (Löve)], intermediate wheatgrass [Thinopyrum Intermedium(Host) Barkworth and Dewey], and reed canarygrass (Phalaris arundinaceaL.). Soil water content was determined by neutron probe for 5 yr on clonal plots grown on a Parshall sandy loam soil (coarse‐loamy, mixed Pachic Haploboroll) near Mandan, ND. A single forage harvest was taken each year when plants were at soft dough stage of seed development. Forage yield and WUE increased the first 2 yr of the study, then decreased for the next 2 yr. Increases and decreases in forage yield were associated with total available water (soil water plus growing season precipitation) prior to harvest and effects of stress in one year on subsequent years. There were no significant (P≥0.05) differences among entries for total water used before harvest. Environmental effects (years and replications) on yield and WUE in each species were large compared with genotypic effects. Genotypic mean squares were from 2 to over 35 times larger than experimental error mean squares for yield and WUE. Broad sense heritability estimates ranged from 71 to 95% for yield and from 69 to 94% for WUE over the four species, which indicated that gain from selection may be possible. However, because of the large year effects, extensive testing will be necessary to evaluate yield and WUE in the four grasses we studied. Development of more effective screening techniques will be necessary to reduce resource input required for evaluating WUE.

Frequently repeated control plots and the moving mean of adjacent plots were compared as methods of controlling error in single‐row plots of barley, Hordeum sativumJess. (H. vulgareL.) Adjustment by either technique was more effective for grain protein content than for grain yield. Covariance adjustment using either moving mean or control plots prevented overadjustment in several instances and was always more effective than percentage adjustment in reducing experimental error. Repeated control plots and moving means gave similar control of experimental error, but control plots had less practical application than moving means. A partially balanced lattice design accomplished superior control to both methods using percentage adjustment and similar control using covariance adjustment. In cases where the number of entries was too large to accommodate an incomplete block design, covariance adjustment using the moving mean would be advantageous.

Intermediate wheatgrass [Thinopyrum intermedium(Host.) Barkworth & Dewey] is susceptible to leaf spot diseases caused by Cochliobolus sativusIto & Kurib., Pyrenophora tritici‐repentis (Died.) Drechs., and Leptosphaeria nodorum E. Müller. These diseases, particularly C. sativus, have potential to reduce forage yield and quality. Development of cultivars with genetic resistance to leaf spot diseases is likely the only economically feasible control measure. Forty intermediate wheatgrass parents and their respective half‐sib families were used to estimate narrow‐sense heritabilities of resistance to leaf spot diseases. Parents and progeny were inoculated with C. sativusand rated for percent necrosis, lesion number, and lesion size in a greenhouse environment. Disease reaction resulting from natural infection by leaf spot pathogens, primarily C. sativus, was rated for 4 yr on parents and 2 yr on progeny in the field. In greenhouse evaluations, lesion size had a narrow‐sense heritability estimate of 36%, while heritability estimates for percent necrosis and lesion number did not exceed 10%. Narrow‐sense heritability for disease scores of parents and progeny that had been established in the field for at least 1 yr ranged from 38 to 97%. Heritability ranged from 6 to 15% for disease scores measured on parents in the establishment year and progeny that had been established for more than 1 yr. Greenhouse measurements of disease reaction were not significantly correlated with field measurements. Thus, selection for resistance to leaf spot diseases in intermediate wheatgrass would be effective only with field plots that had been established for at least 1 yr.

A need exists for drought tolerant forages that can produce acceptable yields on limited water. Techniques to accurately predict performance under drought stress are essential for selection of drought tolerant forages. Objectives of this study were to measure water relations of important forage species using the pressure volume (P‐V) method and to evaluate its usefulness predicting drought tolerance. The study was conducted using clonal selections of crested wheatgrass [Agropyron desertorum(Fisch.) Schult.], western wheatgrass (A. smithiiRydb.), and intermediate wheatgrass [A. intermedium(Link) Haloc.]. Pressure‐volume measurements were made using a pressure chamber on plants grown in both field and glasshouse environments. Data from the P‐V curves for initial turgor loss point, osmotic potential at full hydration and leaf water potential at zero pressure potential indicated differences among genotypes for all three species of wheatgrasses. Although only a limited number of genotypes were evaluated results appear more promising for selecting genotypes for drought tolerance in western than in crested or intermediate wheatgrasses. Species comparisons based on data from the P‐V relationship shows that genotypes of crested and western exhibit water relations that coincide with their greater drought tolerance. The P‐V technique requires a high labor input and will require modifications for practically evaluating large breeding populations for drought tolerance.

A need exists for information on the morphogenesis and water use by forage species to use as a basis to improve management and grazing practices, varietal improvement, and for development of plant growth simulation models. Our objectives were to evaluate morphological development and water use in clonal lines of crested wheatgrass [Agropyron desertorum(Fisch. ex Link) Schult.], western wheatgrass [Pascopyrum smithii(Rhdb.) Löve Syn: A. smithiiRydb.], intermediate wheatgrass [Elytrigia intermedia(Host) Nevsk: Syn: A. intermedium(Host) Beauv.], and reed canarygrass (Pharlaris arundinaceaL.). We also defined the relationship between morphological development, water use, and air temperature expressed as growing‐degree days (GDD) with a base temperature of O°C. The study was conducted during 1981 and 1982 in the field on a Parshall sandy loam soil (coarse‐loamy, mixed Pachic Haploboroll) with two clones of each of two cultivars per species. Number of leaves developed in the spring and GDD per phyllochron varied among species and among clones within a species. Reproductive (spike forming) tillers of clonal lines of crested wheatgrass and western wheatgrass developed six leaves with 557 and 778 GDD, respectively; intermediate wheatgrass, seven leaves with 780 GDD; reed canarygrass, eight leaves with 706 GDD. Number of GDD required to develop a single leaf was 84 for reed canarygrass, 104 for crested wheatgrass, 125 for intermediate wheatgrass, and 147 for western wheatgrass. Western wheatgrass extracted soil water from a deeper soil depth and to a lower content than the other species. Dry matter yields were highest in intermediate wheat‐grass and lowest in western wheatgrass. Water‐use‐efficiency (WUE) was highest in crested wheatgrass and lowest in western wheatgrass. There were no difference in total water used among clones within any species. Among the three wheatgrasses, earlier morphological development corresponded to higher WUE. Differences were observed for yield and WUE among crested and western wheatgrass clones.

A leaf‐spot disease of Russian wildrye [Psathyrostachys juncea(Fischer) Nevski] caused by Septoria spragueiUecker & J.M. Krupinsky has the potential to reduce forage quality and yield, particularly in subhumid portions of the northern Great Plains region of the USA and Canada. This study was conducted to estimate heritability of resistance to S. spragueiand to measure the correlation between disease ratings in greenhouse and field environments. Twenty‐five parent clones and their respective half‐sib families were inoculated with S. spragueiin a greenhouse environment and subjected to natural infection in a field nursery. In the greenhouse, narrow‐sense heritability (h2) estimates from the regression of half‐sib family means on parent means were 0.57, 0.79, and 0.72, respectively, for lesion number, lesion size, and percentage necrosis ratings on leaf blades. Heritability estimates in the field environment were 0.22, 0.57, and 0.36, respectively, for lesion number, lesion size, and percentage necrosis. Lesion size was the only rating for which the entry × year interaction was nonsignificant in the field for both parents and half‐sib families. The Spearman rank correlation coefficient between greenhouse and field environments for lesion size means of half‐sib families was 0.61**. Recurrent phenotypic selection for small lesion size among half‐sib families inoculated with S. spragueiin a single greenhouse environment should be effective in improving resistance to this leaf‐spot disease in Russian wildrye.

Related barley (Hordeum vulgareL.) lines, with small‐ and large‐leaf areas were developed and used to study the effect of leaf area on photosynthesis, light penetration, and grain yield. An infrared gas analyzer was used to measurep hotosynthesis of flag leaves in the laboratory and photosynthesis of plant canopies in the field. Light penetration into plant canopies was measured with tube solarimeters. LAI, grain yield, and the components of yield were determined in field plots. Photosynthetic rates per unit leaf area in the laboratory were similar in small and large flag leaves; thus, total photosynthetic activity per leaf was about twice as great in the large flag leaves. In field comparisons, however, no consistent differences in photosynthetic rates of small‐ and large‐leaf canopies could be detected, even though LAI's were greater in large‐ than in small‐leaf canopies by 19% in Population I and by 33% in Population II. Photosynthesis in the barley canopies as a whole was limited by lack of light throughout the entire range in intensity of solar radiation. In yield trials large‐leaf lines exceeded small‐leaf lines in flag leaf area by 70% and in LAI by 25%. Lines with small leaves produced more heads and higher grain yields than lines with large leaves when plants did not lodge. Where lodging occurred, however, large‐leaf lines had higher kernel weights and were higher yielding. We postulate that large leaves favor higher kernel weights and that small leaves favor production of more culms.