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ABSTRACT:Utah sweetvetch (Hedysarum boreale Nutt. [Fabaceae]) is a perennial legume native to the Intermountain Region of the western US and Canada. 'Timp', the only cultivar of this species, has poor seed production. Here we report the release of 'Basin' Utah sweetvetch as a replacement for Timp for use in revegetation of rangelands in the Intermountain Region of the western US. Basin is derived from 3 cycles of recurrent selection for increased seed and forage mass production, and it traces to 16 germplasm sources originating from Alaska, Colorado, Idaho, and Utah. In 3 y of testing, Basin exceeded Timp in seed yield, with 682 compared to 320 kg/ha (608 compared to 285 lb/ac), and in forage biomass at 1263 compared to 659 kg/ha (1126 compared to 588 lb/ac). Crude protein and neutral detergent fiber, measures of forage nutritive value, of Basin were comparable, if not better, than alfalfa. The release of Basin provides seed companies and public and private land managers an improved Utah sweetvetch with increased seed and forage production for revegetation projects in the Intermountain areas of the western US. Specifically, its increased seed production should increase seed availability and thus, reduce the price.

Well‐managed irrigated pasture production can be optimized without nitrogen (N) fertilizer. The objective was to determine mixture and planting ratios of tall fescue (Schedonorus arundinaceaSchreb.) (TF), meadow brome (Bromus ripariusRehm.) (MB), orchardgrass (Dactylis glomerataL.) (OG), timothy (Phleum pratenseL.) (TIM), and perennial ryegrass (Lolium perenneL.) (PRG) with alfalfa (Medicago sativaL.) (ALF), birdsfoot trefoil (Lotus corniculatusL.) (BFTF), or cicer milkvetch (Astragalus cicerL.) (CMV) that maximize productivity. Planting ratios were 0:100 (grass:legume), 25:75, 50:50, 75:25, and three 100:0 grass monocultures fertilized at 0, 67, and 134 kg N ha−1. Seasonal production of TF–ALF was 12.69 Mg ha−1, equal to TF fertilized at 134 kg N ha−1. ALF mixtures with MB, OG, TIM, and PRG produced 12.57, 10.97, 11.77, and 10.74 Mg ha−1, respectively, and 8 to 40% more than grasses receiving 134 kg N ha−1. Production of BFTF mixtures with TF, MB, and OG were 11.69, 11.45, and 9.95 Mg ha−1, respectively, equal to their respective grass monoculture receiving 134 kg N ha−1. The BFTF–TIM and BFTF–PRG mixtures averaged 12% more forage than grass monocultures receiving 134 kg N ha−1. Production of CMV‐grass was similar to that of grasses receiving 67 kg N ha−1. Seasonal forage distribution was more uniform in ALF– and BFTF–grass mixtures, averaging 30% more at the second and third harvests than fertilized grasses. The TF and MB legume mixtures averaged 7% more production in the 50:50 planting ratios than the other two grass–legume mixtures, while the 50:50 and 25:75 ratios of OG and TIM–legume mixtures averaged 12% more than the 75:25 and the 25:75 PRG–legume planting ratio averaged 9% more than the 50:50 and 75:25. Forage production of grass–legume mixtures can equal or exceed fertilized grass monocultures and with more uniform distribution over the growing season.

We conducted greenhouse experiments to compare 14 lucerne (alfalfa, Medicago sativa L.) germplasms for their survival following freezing. Some are collections adapted to the Grand River National Grasslands in South Dakota. We hypothesised that these collections might have developed a tolerance to survive the frigid growth conditions common there. Two of these collections, River side (RS) and Foster ranch (FR), showed greater freezing tolerance than the other germplasms tested, based on their consistent survival rates with or without cold acclimation. In multiple freezing studies, RS and FR had average survival rates of 74% and 79%, respectively, in contrast to the commercial cultivars Apica and CUF-101 (CUF) (64% and 24%, respectively). The average temperature at which 50% of ions in plant tissues leak out (LT50) by freezing based on leaf electrolyte leakage was closely correlated with survival rates. Leaf LT50 improved 2–3-fold after 3 days of cold acclimation, based on leaf electrolyte leakage analysis, reaching -18°C, –9.6°C, –8.5°C, and -5°C for RS, FR, Apica, and CUF, respectively. Comparison of total soluble sugars and relative water content in shoots before and after cold acclimation showed that they were not well correlated with freezing tolerance and could not explain the superior responses of RS and FR during cold acclimation. Transcript analysis of cold-responsive MsCBF1, MsCBF2 and CAS15B genes showed that RS, FR, Apica and CUF exhibited distinct patterns of cold induction. Although RS, FR and Apica showed a rapid or greater increase in expression level of one or two of these genes, CUF showed only a moderate induction in MsCBF2 and CAS15B transcripts, suggesting that expression of these genes may be a good molecular marker for freezing tolerance in lucerne. The findings provide evidence that freezing tolerance in lucerne is a complex trait and that a combination of different mechanisms may greatly improve freezing tolerance. RS and FR are potential resources in breeding for improving freezing tolerance in lucerne.

Sweetvetch (Hedysarum borealeNutt.) is purported to tolerate glyphosate [N‐(phosphonomethyl) glycine]. Eight rates of glyphosate were tested for their effect on biomass (BM) and survival of seedlings and mature plants. Rates were 0, 210, 420, 841, 1681, 3363, 6725, and 13,450 g a.e. ha–1. Tall fescue (Festuca arundinaceaeSchreb.) was included as a susceptible check. Doses required to cause 50% reduction (GR50) in sweetvetch seedling BM was 5025 and 1636 g a.e. ha–1at first and second harvests, respectively. Tall fescue seedling BM GR50values were 373 and 512 g a.e. ha–1at first and second harvests, respectively. Seedling mortality in sweetvetch was not sufficient to estimate an LD50; however, in tall fescue the seedling LD50was 987 g a.e. ha–1. Four weeks after spring field treatments, sweetvetch and tall fescue BM GR50values were 3467 and 549 g a.e. ha–1, respectively. Thirteen months later BM GR50estimates were 11,595 and 886 g a.e. ha–1for sweetvetch and tall fescue, respectively. Fall‐applied glyphosate did not reduce BM in the sweetvetch sufficient to estimate a GR50. Tall fescue estimated BM GR50was 413 g a.e. ha–1. At the three lowest treatments BM of sweetvetch mature plants was unaffected. Survival of mature sweetvetch plants was ≥70% precluding estimates of LD50values. The LD50's for tall fescue spring and fall treatments was 751 and 541 g a.e. ha–1, respectively. Based BM GR15values sweetvetch will withstand a glyphosate rate of 670 g a.e. ha–1with no mortality or negative effect on subsequent harvests.

Sainfoin (Onobrychis viciifoliaScop.), a nonbloating forage legume, is purported to have tolerance to glyphosate [N‐(phosphonomethyl) glycine]. The effect on biomass yield (BMY) and survival of eight rates of glyphosate on seedlings and mature plants were determined. Treatment rates were 0, 210, 420, 841, 1681, 3363, 6725, and 13,450 g ae ha−1. Alfalfa (Medicago sativaL.) was included as susceptible check. The dose required to produce a 50% reduction (GR50) in sainfoin seedling BMY was 868 and 2984 g ae ha−1at the first and second harvests, respectively. Alfalfa seedling BMY GR50values were 331 and 463 g ae ha−1at the first and second harvests, respectively. The dose estimated to cause 50% mortality (LD50) in sainfoin seedlings was beyond the highest treatment rate at 14,016 g ae ha−1, compared with alfalfa at 2068 g ae ha−1. Four weeks after a spring treatment, sainfoin and alfalfa mature plant BMY GR50values were 2622 and 208 g ae ha−1, respectively. Biomass yield GR15values from the same spring treatment were 1030 g ae ha−1for sainfoin and 66 g ae ha−1for alfalfa. Thirteen months following the spring treatments sainfoin and alfalfa GR50values averaged 11,007 and 1093 g ae ha−1, respectively. Fall applied glyphosate BMY GR50values from harvests the following spring were 12,949 g ae ha−1for sainfoin and 755 g ae ha−1for alfalfa. The LD50for sainfoin spring and fall treatments on mature plants was estimated to be well beyond the highest treatment rate 13,450 g ae ha−1. The average LD50for mature alfalfa plants was 583 g ae ha−1. Based on the LD50values, sainfoin seedlings are over six times more tolerant, and mature plants over 20 times more tolerant to glyphosate than alfalfa. Based on the GR50values, glyphosate has a 10‐fold greater negative impact on alfalfa BMY than it does on sainfoin; however, the GR15values indicate a likely reduction in sainfoin BMY at glyphosate rates in the range of 841 g ae ha−1.

‘Snowstorm’ (Reg. No. CV‐8, PI 666938) forage kochia [Bassia prostrata(L.) A.J. Scott; syn. Kochia prostrata(L.) Schrad.] was released on 22 Mar. 2012 by the USDA‐ARS and the Utah Agricultural Experiment Station. Snowstorm was evaluated as OTVSEL and Otavny‐select and was developed as a synthetic cultivar using two cycles of recurrent selection for stature, forage production, and adaptation to semiarid environments. Snowstorm was compared with the standard forage kochia cultivar, Immigrant, and other ARS experimental forage kochia populations. Research has shown that Immigrant can increase rangeland productivity three‐ to sixfold and provides critical protein (>70 g kg−1) during the fall and winter for livestock and wildlife; however, Immigrant is easily covered by snow because of its short stature. In field comparisons with Immigrant, Snowstorm was similar to Immigrant in establishment and adaptation on semiarid rangelands but was 64% taller (77 versus 47 cm), produced 68% more forage (2526 versus 1504 kg ha−1), and had a 22% higher protein content (79 versus 65 g kg−1) and 4% higher digestibility (674 versus 648 g kg−1) (P≤ 0.05). Furthermore, DNA fingerprinting showed that Snowstorm, Immigrant, and experimental populations were genetically unique and distinct from each other. Snowstorm is named for its ability to extend the grazing season into the fall and winter and because it provides ranchers and land managers a new, taller, more productive, more nutritious forage kochia cultivar capable of increasing carrying capacity and nutritional content of fall and winter grazinglands, including locations where snow cover had limited forage kochia use in the past.

The choice of plant materials is an important component of revegetation following disturbance. To determine the utility and effectiveness of various perennial grass species for revegetation on varied landscapes, a meta analysis was used to evaluate the stand establishment and persistence of 18 perennial cool-season grass species in 34 field studies in the Intermountain and Great Plains regions of the United States under monoculture conditions. Combined across the 34 studies, stand establishment values ranged from 79% to 43% and stand persistence values ranged from 70% to 0%. Intermediate wheatgrass (Thinopyrum intermedium[Host] Barkworth & D. R. Dewey), tall wheatgrass (Thinopyrum ponticum[Podp.] Z.-W. Liu & R.-C. Wang), crested wheatgrass (Agropyronspp.), Siberian wheatgrass (Agropyron fragile[Roth] P. Candargy), and meadow brome (Bromus ripariusRehmann) possessed the highest stand establishment (≥ 69%). There were no significant differences among the 12 species with the largest stand persistence values. Basin wildrye (Leymus cinereus(Scribn. & Merr.) Á. Löve), Altai wildrye (Leymus angustus[Trin.] Pilg.), slender wheatgrass (Elymus trachycaulus[Link] Gould ex Shinners), squirreltail (Elymusspp.), and Indian ricegrass (Achnatherum hymenoides[Roem. & Schult.] Barkworth) possessed lower stand persistence (≤ 32%) than the majority of the other species, and Indian ricegrass (0%) possessed the lowest stand persistence of any of the species. Correlations between environmental conditions and stand establishment and persistence showed mean annual study precipitation to have the most consistent, although moderate effect (r = ∼0.40) for establishment and persistence. This relationship was shown by the relatively poor stand establishment and persistence of most species at sites receiving less than 310mm of annual precipitation. These results will be a tool for land managers to make decisions concerning the importance of stand establishment, stand persistence, and annual precipitation for revegetation projects on disturbed sites.

‘Recovery’ western wheatgrass [Pascopyrum smithii(Rydb.) Barkworth & D. R. Dewy] (Reg. No. CV‐32, PI 660509) was released in December 2009 by the USDA‐ARS, the Engineer Research and Development Center of the U.S. Army Corps of Engineers, and the USDA‐NRCS. Recovery was developed for reseeding rangelands following severe disturbance, frequent fires, and soil erosion, and it was selected with emphasis on improved and faster seedling establishment. Recovery was evaluated as TC3, TC‐Rich, Army WWG, SERDP WWG, and NRCS‐9076517 and was developed as a synthetic cultivar using two cycles of recurrent selection for plant vigor, seed yield, and rate of seedling emergence from a deep planting depth. In field evaluations, Recovery had an increased frequency of seedlings during the establishment year, when averaged across eight locations, than ‘Arriba’, ‘Barton’, ‘Flintlock’, ‘Rodan’, and ‘Rosana’ western wheatgrasses. Recovery continued to have superior stand until 4–6 yr after planting, when due to their rhizomatous nature, all the western wheatgrasses had similar stand frequencies. Recovery western wheatgrass provides land managers with a new western wheatgrass cultivar possessing rapid establishment for use in areas that are frequently disturbed, such as military training lands. The use of Recovery will help reduce soil erosion and weed invasion following such disturbances.

Abstract:A system for staging sweetvetch (Hedysarum borealeNutt. [Fabaceae]) through vegetative and reproductive plant development was established that corresponds with a heat unit or growing degree day (GDD) model. This framework designates 14 finite stages, V1 through V6 (pre-flowering or vegetative), and R1 through R8 (reproductive stages). The arrangement provides meaningful designations for management of the plant for seed production. Of 5 base temperatures tested in the development of the GDD model, 40 °F (4.4 °C) most accurately predicted the growth of sweetvetch through the 6 vegetative and 8 reproductive developmental stages. The GDD model showed that on average, each growth stage above V2 (pre-bud, 2 visible nodes) requires 118 GDD. Critical stages in the development of sweetvetch for seed production are late bud, flowering, pod formation, and seed maturity, which require 605, 841, 1076, and 1547 GDD, respectively. The proper application of this staging system and model can be useful for seed producers and collectors by providing an estimate of when the plant will reach critical growth stages, particularly for management of irrigation, insect pest control, and harvest. Historical temperature data could be used to predict the average calendar date when sweetvetch will reach a given growth stage, or where real-time data are available, dates of stages may be accurately predicted.

Abstract:A system for staging sweetvetch (Hedysarum borealeNutt. [Fabaceae]) through vegetative and reproductive plant development was established that corresponds with a heat unit or growing degree day (GDD) model. This framework designates 14 finite stages, V1 through V6 (pre-flowering or vegetative), and R1 through R8 (reproductive stages). The arrangement provides meaningful designations for management of the plant for seed production. Of 5 base temperatures tested in the development of the GDD model, 40 °F (4.4 °C) most accurately predicted the growth of sweetvetch through the 6 vegetative and 8 reproductive developmental stages. The GDD model showed that on average, each growth stage above V2 (pre-bud, 2 visible nodes) requires 118 GDD. Critical stages in the development of sweetvetch for seed production are late bud, flowering, pod formation, and seed maturity, which require 605, 841, 1076, and 1547 GDD, respectively. The proper application of this staging system and model can be useful for seed producers and collectors by providing an estimate of when the plant will reach critical growth stages, particularly for management of irrigation, insect pest control, and harvest. Historical temperature data could be used to predict the average calendar date when sweetvetch will reach a given growth stage, or where real-time data are available, dates of stages may be accurately predicted.

Poais a complex genus taxonomically and genetically. As a result, relatively little information exists for this economically important genus with regards to reproductive mode and variability in chromosome number. We examined apomixis frequency and ploidy levels in 83 Poaaccessions representing 33 species from the National Plant Germplasm System using flow cytometric techniques. In reproductive mode analysis, we analyzed at least three preparations of 50 seeds each from the accessions. In ploidy level analysis, at least three plants of each accession were analyzed. Sixty percent of the species had at least one apomictic or facultative apomictic accession; 40% were sexual. Thirty‐three percent of the species had no sexual accessions. Autonomous apomixis was newly identified in P. bactrianaand P. bulbosain addition to it being previously reported in P. nervosa. Poa annua and P. trivialiswere identified as obligate sexual, and P. nervosaas obligate apomictic. Two of four P. palustrisaccessions exhibited facultative apomixis. Ploidy levels among sexually reproducing Poaaccessions ranged from 2n= 2x= 14 to 2n= 12x= 84, with most accessions between 2n= 3x= 21 to 2n= 8x= 56. Among apomictic accessions, ploidy levels ranged from 2n= 3x= 21 to 2n= 10x= 70, with most between 2n= 4x= 28 and 2n= 10x= 70. These results emphasize the wide variability in Poa, both among and within species.

Small burnet (Sanguisorba minorScop.) is an evergreen forb readily utilized by livestock and wildlife that lacks persistence under heavy grazing. Our objective was to characterize all available National Plant Germplasm System (NPGS) small burnet germplasm for ploidy level and agronomic characteristics before initiating a breeding program. Ploidy level was determined by flow cytometry. Forage yield, flowering date, mortality, growth habit, and leafiness were determined at two locations in Utah. Of the materials tested 68% were tetraploids (2n= 4x= 28) and 32% octaploids (2n= 8x= 56). Significant variation was observed for all traits. Mean forage yield of the small burnet was 1.45 Mg ha−1, ranging from not measurable to 2.96 Mg ha−1compared to Ladak alfalfa (Medicago sativaL.) at 2.28 mg ha−1Flowering date varied among accessions by 12 d while mortality ranged from 0 to 100%. Variation was displayed in growth habit, including prostrate and upright forms, and leafiness. The range among accessions was similar within the two ploidy levels for all traits except flowering date which was 2 d earlier in the octaploids. It was shown that tetraploids and octaploids are present in roughly a 2:1 ratio in the NPGS small burnet germplasm. The forage production of some small burnet accessions can be comparable to alfalfa, and phenotypic variation is such that the germplasm has potential for improvement through recurrent selection.

‘Don’ (Reg. No. CV‐205, PI 655519), a diploid falcata alfalfa (Medicago sativasubsp falcataL.), was developed by the Forage and Range Research Laboratory in Logan, UT, in cooperation with the Utah Agricultural Experiment Station, Utah State University. Recent interest in falcata alfalfa has been high due to its value for increasing the productivity of rangelands. Don was selected for persistence under harsh conditions, uniform yellow flower color, increased seed production, and large‐stature plants. Don traces to PI20725, an original collection made by N.E. Hansen in the Don Province of Russia. Don was tested as AU021. Don is significantly more persistent than typical sativa (M. sativaSubsp sativaL.)–type alfalfas and is meant for use in mixed plantings with grasses either in range or pasture situations typical of the Intermountain region of the western United States. In comparative trials, including irrigated and nonirrigated, where 25 to 50% mortality was observed on sativa alfalfas, Don showed no mortality. When used in mixtures, the production advantage of Don with tall fescue [Schedonorus phoenix(Scop.) Holub; syn. Festuca arundinaceaeSchreb.] and meadow brome (Bromus ripariusRehm.) ranged from 10 to 32% When Don is grown with crested wheatgrass on dry rangelands, similar production advantages are expected, which will make rangelands more productive. Furthermore, when grown in mixtures with grasses, Don will not dominate; rather, it has a low growth habit and stays well below the canopy of most cool‐season grasses.

The validity of spaced‐plant evaluation to determine sward performance of forage grasses has been questioned. This experiment studied the efficiency of spaced‐plant evaluation to indirectly improve sward yield and nutritional quality in tall fescue (Festuca arundinaceaSchreb.). Narrow‐sense heritabilities, genetic and rank correlations, and indirect selection efficiencies were estimated for a tall fescue population grown in spaced plant and seeded sward environments. Heritability for yield was similar between spaced plants and swards (0.43 and 0.44, respectively), but genetic correlation between the two was low (0.37 ± 0.38). Inconsistency (r= 0.30, P= 0.17) in family ranking further suggested that spaced plants were not predictive of sward yield. Heritability of crude protein from swards was low (0.27 ± 0.25) compared with 0.77 ± 0.08 from spaced plants, but there was no genetic relationship between the two (r= −0.13 ± 0.30). Moderate to high heritabilities and genetic correlations were observed for most fiber traits, but indirect selection efficiencies and rank correlations of <1.0 suggested that evaluation in a sward environment would be best to select for improved nutritional quality. Spaced‐plant evaluation appears to be less effective, or ineffective, at improving sward yield and nutritional quality in tall fescue. New techniques are needed that maximize genetic expression but simulate actual sward production of forage grasses.

Hedysarum borealeNutt. is a perennial legume native to western North America, with robust foliage in the late spring season. Due to its wide native range, forage value, and N2fixation, H. borealeis of interest for rangeland revegetation and production. Seed cost is a major obstacle for utilization of H. boreale, primarily due to seed shattering and unreliable seed production, such that a need for improved germplasm exists. This study characterized the genetic relationships of H. borealeaccessions, so plant breeders and geneticists will have the information necessary to maintain a broad genetic base within selected germplasm populations. Amplified fragment length polymorphism markers were used on 17 available accessions from Utah, Idaho, Colorado, and Alaska. Seventy percent of the total genetic variation was found within all 17 accessions, yet each accession showed significant isolation by distance. Genetic diversity within accessions was greatest in sites located in eastern Utah. The sole cultivar, Timp, had slightly greater genetic diversity than a collection made from the same site approximately 20 yr later. Two groups of metapopulations were identified in Utah, separated longitudinally approximately along the Wasatch mountain range.

Meadow bromegrass (Bromus ripariusRehm.) has gained interest as a highly productive pasture grass that can be used under management intensive grazing with limited irrigation. In 1999, 28 cloned parents and half‐sib families of meadow bromegrass were each planted in a randomized complete block design to evaluate genetic variation of meadow bromegrass for dry matter yield (DMY) (Harvests 1 to 6), forage quality under repeated defoliation (Harvests 1, 3, and 5), and investigate intercharacter correlations. Narrow‐sense heritability estimates and their standard errors for DMY at Harvests 2, 3, and 4 were 0.89 ± 0.32, 0.59 ± 0.28, and 0.53 ± 0.29, respectively. However, at Harvest 1 and 5, standard errors of the heritability estimates for DMY were equal to or greater than the estimates. All heritability estimates for crude protein (CP) were at least twice their standard errors at Harvests 1, 3, and 5. High narrow‐sense heritabilities at Harvest 5 for acid detergent fiber (ADF) suggest that selection on forage harvested later in the growing season might be more efficient than forage harvested earlier in the season. Combined across years and within harvests, narrow‐sense heritability estimates and standard errors for neutral detergent fiber (NDF) were 0.66 ± 0.29, 0.47 ± 0.30, and 0.71 ± 0.28, respectively. Based on correlations, it seems reasonable to assume that when selecting for increased DMY that ADF and NDF will increase and that CP and IVTD will decrease in this population.

Difficulties associated with producing high quality forage on salt affected soils is often associated with the inability of plants to establish and persist at elevated soil salinity levels. The cultivar NewHy RS‐wheatgrass is recommended for use on range sites with moderate salinity problems that receive at least 35 cm of annual precipitation. Objectives of this study were to evaluate (i) the ability to improve plant persistence in NewHy over three cycles of greenhouse selection at increased salinity levels and (ii) corresponding changes in seedling vigor and germination under nonsaline conditions. Greenhouse grown plants were irrigated every 3 d with a complete nutrient solution and salt levels were increased by an electrical conductivity (EC) of 6 dS m−1every 1 to 2 wk until an EC level of 42 dS m−1was reached and maintained until plant mortality occurred in 2002 and 2003. Probit analysis was used to estimate the time and salt concentration required to kill 50% of the plants (LD50) in each cycle. Significant differences for LD50were found among the different cycles of NewHy selected for persistence under saline conditions and the quackgrass [Elytrigia repens(L.) Nevski] parent with a resulting ranking of Cycle‐3 > Cycle‐2 > Cycle‐1 > quackgrass > NewHy (Cycle‐0). The largest single gain was achieved from NewHy Cycle‐0 to Cycle‐1, which required an additional 145 ECdays to reach an LD50level. Smaller increases were observed between Cycles‐1 and ‐2 and between Cycles‐2 and ‐3. Selection for persistence under a saline environment did not reduce seedling germination rate or vigor.

A lack of salt‐tolerant cultivars may be due in part to inadequate evaluation protocols used for selection. Our objective was to develop a greenhouse protocol that is simple and consistently separates genotypes for their relative ability to survive under saline conditions. In 2000 and 2001, 12 alfalfa (Medicago sativaL.) cultivars were seeded in 3.8‐ by 21‐cm cone‐shaped containers plugged with capillary matting and filled with silica sand. Six‐week‐old seedlings were submersed in a NaCl‐nutrient solution starting at an electrical conductivity (EC) of 3.0 dS m−1and increased 3.0 dS m−1every 1 to 2 wk for 10 to 13 wk. Probit analysis was used to estimate the time and salt dose to reach 50 (LD50) and 75% (LD75) mortality. Probit results were compared with cultivar ranking for mean percentage plant mortality when overall trial mortality reached approximately 50 and 75%. Pearson's rank correlations between 2000 and 2001 at the LD50and LD75levels were r= 0.90 (P< 0.001) and r= 0.88 (P< 0.001), respectively. Rank correlations between 2000 and 2001 based on means when overall trial mortality levels were approximately 50 and 75% were r= 0.92 (P< 0.001) and r= 0.85 (P< 0.001), respectively. The correlations between mean percentage cultivar mortality rankings and the probit‐based rankings were above r= 0.90 (P< 0.001) in both years. The high correlations verify that this protocol produces repeatable results and provides a method to effectively screen large numbers of plants for survival under saline conditions.

Limited water and curtailed use of public lands for grazing has increased interest in intensively managed pastures in the western USA. Our objective was to evaluate forage production of sainfoin (Onobrychis viciifoliaScop.), a nonbloating legume, compared with alfalfa (Medicago sativaL.). Thirteen sainfoin cultivars and ‘Deseret’ alfalfa were evaluated at four water levels (WLs) and four harvests in 1998 and 1999 under a line‐source irrigation system. Water levels (WL1, WL2, WL3, and WL4) received an average of 78.3, 65.8, 34.9, and 8.3 cm of water, respectively. Significant effects were found for cultivar, cultivar × WL, harvest date, and cultivar × harvest date. Annual production of sainfoin at WL1, WL2, WL3, and WL4 was 11.6, 11.4, 9.6, and 8.9 Mg ha−1, respectively, whereas annual production of Deseret was 20.7, 18.5, 18.0, and 16.3 Mg ha−1, respectively. Overall yield trends across WLs were linear for sainfoin and Deseret and were parallel (P= 0.55) with slopes of b= 0.042 and b= 0.054, respectively. Yield of sainfoin at Harvest 1 through 4 was 5.5, 2.1, 1.5, and 1.3 Mg ha−1, respectively. Yield of Deseret from Harvest 1 through 4 was 5.9, 5.3, 4.7, and 2.4 Mg ha−1, respectively. Yields of the two species at Harvest 1 did not differ. The flat linear trend across WLs verifies that both crops are tolerant to dry conditions. With its highest production potential during early growth, sainfoin is best suited for situations where early growth of a nonbloating legume is desired, but will not compete with alfalfa in total seasonal production.

In mature plant breeding programs an elite core germplasm forms the backbone of the breeding effort, confronting the breeder with the challenge of maintaining germplasm diversity as genetic distance between the elite core germplasm and donor germplasm widens. This research assessed the effects on grain yield of transferring genes from two‐row barley (Hordeum vulgareL.) cultivars to a six‐row gene pool. We conducted three cycles of recurrent‐type breeding, beginning with crosses involving five two‐row donor parents. The crossing scheme led to progenies with theoretical proportions of two‐row germplasm of 25 to 50% in Cycle 1, 12.5 to 25% in Cycle 2 and 6.25 to 12.5% in Cycle 3. In Cycle 1, yield of the six‐row progeny across the five populations ranged from 86 to 97% of the respective six‐row parent. Kernel weight of the six‐row progeny was also low in Cycle 1. In Cycle 2, grain yield improved to 99% of the check mean and kernel weight improved to 102% of the check mean. In Cycle 3, sets of lines representing three populations yielded from 112 to 119% of the check mean in 1997 and 1998 and individual lines surpassed ‘Stander’, the highest yielding check in both 1997 to 1998. The highest yielding lines in each cycle were derived from populations having the highest theoretical percentage of adapted recurrent parent germplasm, that is, when six‐row gene combinations were predominately left intact. Results from the three breeding cycles support the proposition that a strategy that maintains favorable gene combinations while introgressing relatively small amounts of donor germplasm can lead to incremental yield gains.

Four B111hybrids (2n= 9x= 63, ABDStStYYWW) were obtained between wheat (Triticum aestivumL., 2n = 6x = 42, AABBDD) and a diplosporic and 2n‐pollen‐producing Elymus rectisetus(2n= 6x42, StStYYWW) accession. We determined whether apomeiosis and 2npollen formation, which occur in the male parent, also occur in the Bill hybrids. Pistils were cleared for UV microscopy of callose and recleared for cytological observations using interference contrast microscopy. Callose fluorescence from most megaspore mother cells (MMCs) was typical of sexual species. These were classified as sexual. Abnormally elongated MMCs with walls devoid of callose were observed in 4.7% of pistils collected at meiotic prophase. These traits are typical of many apomeiotic MMCs in E. rectisetus. Asynapsis followed by mitosis in pollen mother cells (PMCs) consistently preceded unreduced pollen formation in E. rectisetus. This was not observed in the B11lhybrids, though the following meiotic anomalies were observed: (i) asynapsis, aggregation of chromosomes to several poles, and multiple divisions to form four to eight unbalanced microspores, and (ii) incomplete synapsis, formation of anaphase I laggards, and a second division resulting in four unbalanced microspores with micronuclei. The wheat haplome enforced PMC meiotic pairing (albeit abnormal) among homologous E. rectisetuschromosomes and generally inhibited apomeiosis, also by enforcing meiosis. Diplospory may be caused by the expression of embryo sac signals from one genome precociously expressed with megasporogenesis signals from another. If this is correct, the successful induction of apomixis in wheat may require the transfer of alien gene cassettes that confer appropriate degrees of reproductive asynchrony.

Callose, a β‐l,3‐glucan, is synthesized and deposited in the walls of megaspore mother cells (MMCs) of angiosperms that produce either normal monosporic (>90% of all angiosperm species) or bisporic embryo sacs. Such deposits are absent in angiosperms that produce tetrasporic embryo sacs and were recently shown to be absent in diplosporous Elymus rectisetus(Nees in Lehm.) A. Löve & Connor, TripsacumL. spp., and Poa nemoralisL. We determined the extent of callose deposits in MMCs of diplosporous weeping lovegrass (Eragrostis curvulaSchrad.), several additional diplosporous Tripsacumaccessions and aposporous buffelgrass (Pennisetum ciliare(L.) Link), Kentucky bluegrass (Poa pratensisL.), and Pennisetum squamulatumFresen. Callose deposition was studied in pistils cleared in an aqueous aniline blue clearing medium and observed by means of UV microscopy. Pistils cleared with conventional clearing media were studied by means of interference contrast microscopy. Some pistils were cleared and analyzed in one clearing medium and recleared and reanalyzed in the other. A callosic MMC was observed in only one of 376 appropriately staged pistils taken from diplosporous species. This pistil, one of 89 weeping lovegrass pistils studied, was probably facultatively sexual. An absence of callose during megasporogenesis may be characteristic of most types of diplospory. Though present, the distributions and quantities of callose observed in MMC walls of aposporous apomicts were erratically reduced, possibly as a result of early MMC abortion or early activation of nucellar initials. Callose deficiencies and vacuolization patterns support the following hypotheses: (i) apospory is caused by a moderately precocious gametophytization of nucellar cells, and (ii) bispory, tetraspory, and diplospory are caused by a moderately to extremely precocious gametophytization of the MMC that is nearly complete in the latter case and variably incomplete in the former two cases. Understanding how these precocious gametophytizations evolved and are regulated may be crucial to the eventual transfer of apomixis to major crop species and to its successful manipulation by breeders.