Search

Alfalfa (Medicago sativa L.), one of the most extensively grown forage crops, is sensitive to saline soils. We measured the breeding efficiency for increased salt tolerance in alfalfa by comparing lines selected from BC79S, CS, and SII populations with their unselected parental means for forage mass and associated changes in stem length, leaf-to-stem ratio (LSR), number of nodes per stem, crude protein (CP) content, and neutral detergent fiber (NDF) content. The overall forage mass in the non-salt-stressed test (9562 kg ha−1) was greater (p < 0.001) than under salt stress (5783 kg ha−1), with a 40% production advantage. In the non-salt-stressed test, the BC79S and CS lines averaged at a 4% lower production than their parents, while SII lines had on average a 9% greater production. Conversely, in the salt-stressed test, all lines showed a 20% overall greater seasonal production than their parents. Some selected lines produced more forage mass in both the non-stressed and salt-stressed tests than their parents. The stem length, LSR, node number, CP content, and NDF content of the selected lines varied with respect to non-stressed vs. stressed, but they tended not to differ greatly from their respective parental means under either non- or salt-stressed conditions. The selection protocol provided a universal increase in forage mass under salt-stressed field conditions of the selected lines. Furthermore, we identified lines with forage mass values greater than their parental means under non- and salt-stressed field conditions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Elymus L. is the largest and most complex genus in the Triticeae tribe of grasses with approximately 150 polyploid perennial species occurring worldwide. We report here the first genetic linkage map for Elymus. Backcross mapping populations were created by crossing caespitose Elymus wawawaiensis (EW) (Snake River wheatgrass) and rhizomatous Elymus lanceolatus (EL) (thickspike wheatgrass) to produce [F.sub.1] interspecific hybrids that were then backcrossed to the same EL male to generate progeny with segregating phenotypes. EW and EL are both allotetraploid species (n = 14) containing the St (Pseudoroegneria) and H (Hordeum) genomes. A total of 387 backcross progeny from four populations were genotyped using 399 AFLP and 116 EST-based SSR and STS markers. The resulting consensus map was 2574 cM in length apportioned among the expected number of 14 linkage groups. EST-based SSR and STS markers with homology to rice genome sequences were used to identify Elymus linkage groups homoeologous to chromosomes 1-7 of wheat. The frequency of Stderived genome markers on each linkage group was used to assign genome designations to all linkage groups, resulting in the identification of the seven St and seven H linkage groups of Elymus. This map also confirms the alloploidy and disomic chromosome pairing and segregation of Elymus and will be useful in identifying QTLs controlling perennial grass traits in this genus. Key words: Elymus, SSR, molecular markers, genetic map, thickspike wheatgrass, Snake River wheatgrass, rhizome, growth habit. Le genre Elymus est le plus grand et le plus complexe au sein de la tribu des Triticees au sein des graminees avec plus de 150 especes perennes polyploides distribuees de par le monde. Les auteurs rapportent la premiere carte genetique chez le genre Elymus. Des populations de cartographie issues de retrocroisements ont ete produites en croisant un elyme dru, Elymus wawawaiensis (EW; ? Snake River wheatgrass ?), avec un elyme rhizomateux, Elymus lanceolatus (EL ; Agropyre des rives, ? thickspike wheatgrass ?) pour produire des hybrides [F.sub.1] interspecifiques qui ont ensuite ete retrocroises au meme parent m?le EL pour generer une descendance en segregation. Les especes parentales EW et EL sont toutes deux allotetraploides (n = 14) combinant les genomes St (Pseudoroegneria)et H (Hordeum). Au total, 387 descendants de 4 populations retrocroisees ont ete genotypes avec 399 marqueurs AFLP et 116 marqueurs SSR et STS derives d'EST. La carte consensus qui a ete produite totalise 2574 cM repartis sur les 14 groupes de liaison attendus. Les marqueurs SSR et STS derives d'EST presentant de l'homologie avec des sequences genomiques du riz ont ete employes pour identifier les groupes de liaison homeologues aux chromosomes 1 -7 du ble. La frequence de marqueurs provenant du genome St sur chaque groupe de liaison a ete employee pour la designation de tous les groupes de liaison, de telle maniere que les sept groupes de liaison des genomes St et H ont ete identifies chez les Elymus. Cette carte confirme egalement l'allopolyploidie ainsi que l'appariement et la segregation disomiques des chromosomes chez les Elymus et elle sera utile pour identifier des QTL controlant de nombreux caracteres lies a la perennite au sein de ce genre. Mots-cles : Elymus, SSR, marqueurs moleculaires, carte genetique, thickspike wheatgrass, Snake River wheatgrass, rhizome, port. [Traduit par la Redaction], Introduction Several important cereal crops, cultivated forages, annual and perennial grass weeds, and ecologically diverse grasses belong to the tribe Triticeae (Poaceae). The genus Elymus L. (Poaceae: Triticeae) is composed [...]

Poa is 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 Poa accessions 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. bactriana and P. bulbosa in addition to it being previously reported in P. nervosa. Poa annua and P. trivialis were identified as obligate sexual, and P. nervosa as obligate apomictic. Two of four P. palustris accessions exhibited facultative apomixis. Ploidy levels among sexually reproducing Poa accessions 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 minor Scop.) 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.sup.-1], ranging from not measurable to 2.96 Mg [ha.sup.-1] compared to Ladak alfalfa (Medicago sativa L.) at 2.28 mg [ha.sup.-1]. Flowering 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.

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 arundinacea Schreb.). Narrowsense 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 [+ or -] 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 [+ or -] 0.25) compared with 0.77 [+ or -] 0.08 from spaced plants, but there was no genetic relationship between the two (r = -0.13 [+ or -] 0.30). Moderate to high heritabilities and genetic correlations were observed for most fiber traits, but indirect selection efficiencies and rank correlations of

Hedysarum boreale Nutt. 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 [N.sub.2] fixation, H. boreale is 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. boreale accessions, 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 riparius Rehm.) 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 [+ or -] 0.32, 0.59 [+ or -] 0.28, and 0.53 [+ or -] 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 [+ or -] 0.29, 0.47 [+ or -] 0.30, and 0.71 [+ or -] 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.sup.-1] every 1 to 2 wk until an EC level of 42 dS [m.sup.-1] was 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 (L[D.sub.50]) in each cycle. Significant differences for L[D.sub.50] were found among the different cycles of NewHy selected for persistence under saline conditions and the quaekgrass [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 L[D.sub.50] level. Smaller increases were observed between Cydes-1 and -2 and between Cycles-2 and -3. Selection for persistence under a saline environment did not reduce seedling germination rate or vigor., EXCESS SOIL SALINITY is a major factor limiting the establishment, persistence, and productivity of forage grasses in the Intermountain West. The expanding population and accompanying demand for food, fiber, and [...]

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 sativa L.) 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.sup.-1] and increased 3.0 dS [m.sup.-1] every 1 to 2 wk for 10 to 13 wk. Probit analysis was used to estimate the time and salt dose to reach 50 (L[D.sub.50]) and 75% (L[D.sub.75]) 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 L[D.sub.50] and L[D.sub.75] levels 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., IN SEMIARID REGIONS, limited water and hot dry climates frequently cause salinity concentrations that limit or prevent crop production. At low concentrations salt suppresses plant growth, and at higher concentrations [...]

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 viciifolia Scop.), a nonbloating legume, compared with alfalfa (Medicago sativa L.). 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 x WL, harvest date, and cultivar x 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.sup.-1], respectively. Yield of Deseret from Harvest 1 through 4 was 5.9, 5.3, 4.7, and 2.4 Mg [ha.sup.-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., LOW PRECIPITATION and growing urbanization are placing increased demands on limited water supplies in the Intermountian Region of the western USA. This, coupled with federal land policies that curtail the [...]

Achieving high forage production combined with adequate forage nutritive value on Intermountain western U.S. grazing lands during the fall and early winter can be difficult. Crude protein (CP) and neutral detergent fiber (NDF) of cicer milkvetch (Astragalus cicer L.) were characterized relative to alfalfa (Medicago sativa L.), and crested wheatgrass [Agropyron cristatum (L.) Gaertn.]. Forage was harvested monthly September–December from season long stockpiled growth (full‐season), stockpiled regrowth following a June defoliation (mid‐season), and stockpiled regrowth following an August defoliation (late‐season). Crude protein of cicer milkvetch ranged from 11.9 to 9.2%, 20.5 to 14.3%, and 24.6 to 15.9%, in the full‐, mid‐, and late‐season stockpiled strategies, respectively. Overall, cicer milkvetch CP was equal to alfalfa CP and 5.7 percentage points greater than crested wheatgrass CP across all harvest dates of the three stockpiling scenarios. Furthermore, cicer milkvetch NDF was less (more favorable) than both alfalfa and crested wheatgrass, ranging from 46.4 to 59.6%, 23.0 to 37.4%, and 26.2 to 33.7%, in the full‐, mid‐, and late‐season stockpiled strategies, respectively. The high CP and superior NDF of cicer milkvetch indicate it has unrealized potential for improving forage nutritive value of grazing lands in the western United States, particularly in the late fall to early winter.Core Ideas: Neutral detergent fiber of cicer milkvetch is superior to that of alfalfa and crested wheatgrass through the fall.Crude protein of cicer milkvetch is equal to that of alfalfa and superior to crested wheatgrass.Cicer milkvetch has unrealized potential to improve western U.S. grazing lands, particularly durng late fall. [ABSTRACT FROM AUTHOR]

Callose, a Β-1,3-glucan, is synthesized and deposited in the walls of megaspore mother cells (MMCs) of angiosperms that produce either normal monosporic ([is greater than] 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. Love & Connor, Tripsacum L. spp., and Poa nemoralis L. We determined the extent of callose deposits in MMCs of diplosporous weeping lovegrass (Eragrostis curvula Schrad.), several additional diplosporous Tripsacum accessions and aposporous buffelgrass (Pennisetum ciliare (L.) Link), Kentucky bluegrass (Poa pratensis L.), and Pennisetum squamulatum Fresen. 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 NMC 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., Pure Callose is insoluble in water and is composed of glucans linked together by Β-1,3-glycosidic linkages. Normally, both Β-1,3- and Β-1,4- (cellulose) linkages occur in the same polysaccharide molecule. High [...]

Four [B.sub.III] hybrids (2n = 9x = 63, ABDStStYYWW) were obtained between wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD) and a diplosporic and 2n-pollen-producing Elymus rectisetus (2n = 6x = 42, StStYYWW) accession. We determined whether apomeiosis and 2n pollen 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 [B.sub.III] hybrids, 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. rectisetus chromosomes 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., The Australian wheatgrass Elymus rectisetus reproduces by facultative diplospory. During the early apomeiotic prophase, vacuoles accumulate in the chalazal region of the MMC, the nucleus moves to the center of [...]

High nitrogen (N) fertilizer costs and increased environmental stewardship have renewed interest in grass–legume pastures. This research compared herbage mass, nutritive value, steer growth performance and economics of binary mixtures of tall fescue (Schendonorus arundinaceus [Schreb.] Dumort, nom. Cons.) (TF) with alfalfa (ALF) (TF + ALF, Medicago sativa L.) and birdsfoot trefoil (BFT) (TF + BFT, Lotus corniculatus L.), to tall fescue with (TF + N) and without N fertilizer (TF–N). Pastures were established in Lewiston, Utah, USA, and rotationally stocked by Angus beef steers for 112 days in 2012 and 2013. Herbage samples were collected prior to each 7‐day stocking period and analyzed for mass and nutritive value. Steers were weighed each 28‐day rotation cycle and cumulative average daily gain (ADG) calculated. Steer performance differed (p =.05) among most treatments with ADG greatest for TF + BFT (0.73 kg/day) and TF + ALF (0.67 kg/day), followed by TF + N (0.61 kg/day) and the least for TF–N (0.40 kg/day). Multivariate analysis indicated that small inherent differences in herbage energy, fiber and digestibility were highly correlated with steer growth. Other variables associated with ADG included legume proportion and herbage mass. Fescue–legume mixtures had 29 to 33% legume proportion, and more (p =.05) favorable energy and fiber concentrations than grass monocultures. Whereas herbage mass was greatest (p =.05) for TF + N (2,956 kg/ha), followed closely by TF + BFT (2,741 kg/ha) and TF + ALF (2,623 kg/ha). Overall, TF + BFT and TF + ALF pastures had less herbage, but better nutritive value and increased steer growth performance compared to TF + N, without the added cost of fertilizer. [ABSTRACT FROM AUTHOR]

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 harley (Hordeum vulgare L.) 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. Kernet 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., OLDER PLANT BREEDING PROGRAMS routinely have a core germplasm pool. Use of this core germplasm is important as the breeder attempts to create favorable gene combinations. Industry guidelines and market [...]

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 arundinacea Schreb.) (TF), meadow brome (Bromus riparius Rehm.) (MB), orchardgrass (Dactylis glomerata L.) (OG), timothy (Phleum pratense L.) (TIM), and perennial ryegrass (Lolium perenne L.) (PRG) with alfalfa (Medicago sativa L.) (ALF), birdsfoot trefoil (Lotus corniculatus L.) (BFTF), or cicer milkvetch (Astragalus cicer L.) (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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Sweetvetch (Hedysarum boreale Nutt.) 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 arundinaceae Schreb.) 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-1 at first and second harvests, respectively. Tall fescue seedling BM GR50 values were 373 and 512 g a.e. ha-1 at first and second harvests, respectively. Seedling mortality in sweetvetch was not sufficient to estimate an LD50; however, in tall fescue the seedling LD50 was 987 g a.e. ha-1. Four weeks after spring field treatments, sweetvetch and tall fescue BM GR50 values were 3467 and 549 g a.e. ha-1, respectively. Thirteen months later BM GR50 estimates were 11,595 and 886 g a.e. ha-1 for sweetvetch and tall fescue, respectively. Fall-applied glyphosate did not reduce BM in the sweetvetch sufficient to estimate a GR50. Tall fescue estimated BM GR50 was 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 LD50 values. The LD50's for tall fescue spring and fall treatments was 751 and 541 g a.e. ha-1, respectively. Based BM GR15 values sweetvetch will withstand a glyphosate rate of 670 g a.e. ha-1 with no mortality or negative effect on subsequent harvests. [ABSTRACT FROM AUTHOR]

Sainfoin (Onobrychis viciifolia Scop.), 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 sativa L.) 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-1 at the first and second harvests, respectively. Alfalfa seedling BMY GR50 values were 331 and 463 g ae ha-1 at 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 GR50 values were 2622 and 208 g ae ha-1, respectively. Biomass yield GR15 values from the same spring treatment were 1030 g ae ha-1 for sainfoin and 66 g ae ha-1 for alfalfa. Thirteen months following the spring treatments sainfoin and alfalfa GR50 values averaged 11,007 and 1093 g ae ha-1, respectively. Fall applied glyphosate BMY GR50 values from harvests the following spring were 12,949 g ae ha-1 for sainfoin and 755 g ae ha-1 for alfalfa. The LD50 for 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 LD50 for mature alfalfa plants was 583 g ae ha-1. Based on the LD50 values, sainfoin seedlings are over six times more tolerant, and mature plants over 20 times more tolerant to glyphosate than alfalfa. Based on the GR50 values, glyphosate has a 10-fold greater negative impact on alfalfa BMY than it does on sainfoin; however, the GR15 values indicate a likely reduction in sainfoin BMY at glyphosate rates in the range of 841 g ae ha-1. [ABSTRACT FROM AUTHOR]

Resilience is increasingly part of the discussion on climate change, yet there is a lack of breeding for resilience per se. This experiment examined the genetic parameters of a novel, direct measure of resilience to water deficit in tall fescue (Lolium arundinaceum (Schreb.) Darbysh.). Heritability, genetic correlations, and predicted gain from selection were estimated for average productivity, resilience, and stability based on forage mass of a tall fescue half-sib population grown under a line-source irrigation system with five different water levels (WL). Resilience was both measurable and moderately heritable (h2 = 0.43), with gains of 2.7 to 3.1% per cycle of selection predicted. Furthermore, resilience was not correlated with average response over environments and negatively correlated with stability, indicating that it was not a measure of responsiveness to more favorable environments. Genetic correlations among WL ranged from 0.87 to 0.56, however in contrast, resilience was either not or slightly negatively genetically correlated with WL except for moderate correlations with the 'crisis' WL. Thus, breeding for improved resilience was predicted to have little effect on forage mass at any given individual water deficit environment. Overall, results indicated that this novel metric could facilitate breeding for improved resilience per se to water deficit environments. [ABSTRACT FROM AUTHOR]

Yellow-flowered alfalfa (Medicago sativa subsp. falcata) (also known as sickle medic) has been the cornerstone for breeding alfalfa for dual grazing and hay production in the semiarid regions of the northern Great Plains in the US and Canada. Most, if not all, of the cultivars developed for the northern Great Plains during the 20th century, had parentage tracing back to introductions by Niels Ebbesen Hansen that were obtained from expeditions to Russia, primarily the province of Siberia, on behalf of the United States Department of Agriculture during the early 1900s. The M. falcata genome contains alleles for high levels of drought-tolerance, winter hardiness, and tolerance to grazing, but is generally deficient for commercial seed production traits, such as non-shatter, compared with common alfalfa (M. sativa). A naturalized population, tracing to USDA plant introductions to Perkins County South Dakota by N.E. Hansen in early 1900, and subsequently, facilitated by the determined seed increase and interseeding of a population by a local rancher, Norman 'Bud' Smith, has shown highly desirable in situ characteristics for improving rangelands in the northern Great Plains. This includes adequate seed production to build a seed bank in the soil for natural seedling recruitment and population maintenance/expansion and support the production of a commercial seed source. This review documents the seminal events in the development of cultivars to date and describes novel germplasm with potential for new cultivars in the future. [ABSTRACT FROM AUTHOR]

It has been hypothesized that the genetic control of forage traits, especially biomass, for grass plants growing as spaced-plants versus swards is different. Likewise, the genetic control of compatibility in grass–legume polyculture mixtures is assumed to be different than for forage production in a grass monoculture. However, these hypotheses are largely unvalidated, especially at the DNA level. This study used an intermediate wheatgrass mapping population to examine the effect of three competition environments (spaced-plants, polyculture, and monoculture) on classical quantitative genetic parameters and quantitative trait loci (QTL) identification for biomass, morphology, and forage nutritive value. Moderate to high heritable variation was observed for biomass, morphological traits, and nutritive value within all three environments (H ranged from 0.50 to 0.87). Genetic correlations (rG) among environments for morphology and nutritive value were predominantly high, however, were moderately-low (0.30 to 0.48) for biomass. Six biomass QTL were identified, including three on linkage groups (LG) 1, 6, and 15 that were only expressed in the monoculture environment. Moreover, three biomass QTL on LG 10, 14, and 15 exhibited significant QTL by environment interactions. This study verified that the genetic control of grass biomass in a monoculture versus a grass–legume mixture is only partially the same, with additional genes expressed in monoculture, and that biomass in widely spaced-plants versus swards is predominantly under different genetic control. These results indicate that selection for improved grass biomass will be most successful when conducted within the targeted monoculture or polyculture sward environment per se. [ABSTRACT FROM AUTHOR]

Insufficient dry matter intake (DMI) of pasture by dairy cattle is a major factor limiting growth and milk production; however, it has been hypothesized that some dairy breeds may be more efficient grazers than others. This study was conducted to determine whether dairy breed types differ in DMI and feed efficiency when grazing either grass monoculture or grass-legume mixed pastures. The experiment compared 4 different dairy breed types (Jersey, Holstein, Holstein-Jersey crossbreds, and Montbéliarde-Swedish Red-Holstein 3-breed crossbreds) and 2 levels of pasture type [grass monoculture (MONO) and grass-birdsfoot trefoil (BFT) mixture (MX)] for a total of 8 treatments. Pastures were rotationally stocked with groups of 4 prepubertal heifers for 105 d for 3 yr, and DMI was determined from herbage disappearance. Feed conversion efficiency (FCE) and residual feed intake (RFI) were then derived from DMI, and heifer body weights (BW) and normalized to animal units (AU) as 40% metabolic mature BW of the corresponding dairy breed type to account for inherent differences in size and growth rates. We observed differences in DMI and feed efficiency among breed types and between pasture types. On average, Holsteins had the greatest overall DMI (4.4 kg/AU), followed by intermediate DMI by the crossbreds (4.0 kg/AU), and Jerseys had the least DMI (3.6 kg/AU). Heifers grazing MX pastures had on average 22% greater DMI than those grazing MONO, but heifers on grass monocultures were more efficient in converting DMI to BW gain (i.e., RFI/AU of 0.27 and −0.27, respectively; more negative RFI numbers indicate less DMI to achieve the expected gains). Overall, Jerseys had the most favorable feed efficiency; however, ranking of Holsteins and crossbreds depended upon the feed efficiency metric. This study is one of the first to compare the interaction of dairy breed and pasture quality on grazing efficiency. However, the lack of a breed type × pasture type interaction for DMI, FCE, or RFI indicated that none of these dairy breed types were better adapted than another breed type to pastures with contrasting levels of nutritive value. [ABSTRACT FROM AUTHOR]

Abstract: Alfalfa (Medicago sativa L.) is a major forage crop worldwide that is relatively sensitive to soil salinity. Improved cultivars with high production on saline soil will benefit many producers and land managers. This study reports the characterization of physiological responses of two unrelated experimental alfalfa half-sib families, HS-A and HS-B, selected for their improved survival under saline conditions (up to EC 18). Six-week-old plants were subjected to NaCl-nutrient solution treatment for three weeks starting at an electrical conductivity (EC) of 3 dS m−1 with incremental increases of 3 dS m−1 every week, reaching 9 dS m−1 in the third week. HS-B showed greater leaf number (72%) and stem length (44%) while HS-A showed better leaf production (84%) under salt treatment compared to the initial genetic backgrounds from which they were developed. This improved growth is associated with 208% and 78% greater accumulation of chlorophyll content in HS-B and HS-A, respectively. Both HS-A and HS-B also showed improved capability to maintain water content (RWC) under salt stress compared to the initial populations. Differing from its initial populations (P-B), HS-B did not accumulate Na in shoots after salt treatment. HS-B also maintained K+/Na+ and Ca2+/Na+ ratios, while P-B showed 59% and 69% decrease in these ion ratios, respectively. Na+ content in HS-A was not different from its initial populations (P-A) after salt treatment. However, HS-A showed an enhanced accumulation of Ca2+ and maintained the levels of Mg2+ and K+ in shoots compared to the P-A populations. This study provides physiological support of improved salt tolerance in HS-A and HS-B and suggests that these plants maintain ion homeostasis but have different mechanisms of coping with high salinity. [Copyright &y& Elsevier]

Dairy heifers developed in certified organic programs, especially those utilizing pasture-based management schemes, have lower rates of gain than heifers raised in nonorganic confinement production systems in temperate climates, such as in the Intermountain West region of the United States. This study investigates the effects that different forages in a rotational grazing system have on development of organically raised Jersey heifers. Over 3 years, 210 yearling Jersey heifers were randomly assigned to one of 9 treatments, including a conventional confinement control where animals were fed a total mixed ration or one of 8 pasture treatments: Cache Meadow bromegrass (Bromus riparius Rehmann), QuickDraw orchard grass (Dactylis glomerata L.), Amazon perennial ryegrass (Lolium perenne L.), or Fawn tall fescue (Schendonorus arundinaceus [Schreb.] Dumort) and each individual grass interseeded with birdsfoot trefoil (Lotus corniculatus L., BFT). Each treatment had 3 blocks/yr over the 3-yr period, with each block having a 0.4 ha pasture of each treatment. Every 35 d, over a 105-d period, heifers were weighed and measured for hip height, and blood samples were collected to determine serum insulin-like growth factor-1 and blood urea nitrogen concentrations. Fecal egg counts were also assessed. Heifer body weight (BW), blood urea nitrogen, and insulin-like growth factor-1 concentrations were affected by treatment when analyzed over time. Heifers on grass-BFT pastures had increased BW compared with heifers on monoculture grass pastures. Heifers receiving a total mixed ration or perennial ryegrass+BFT had increased BW gain over the 105-d period compared with heifers grazing tall fescue+BFT, orchard grass, perennial ryegrass, meadow bromegrass, or tall fescue. Individually for all grass species, heifers grazing +BFT pastures had greater ending BW and weight gain than heifers grazing the respective grass monocultures. Furthermore, weight gain for heifers on perennial ryegrass+BFT, meadow bromegrass+BFT, and orchard grass+BFT were not different from those on a total mixed ration. Heifers grazing grass-BFT pastures had increased blood urea nitrogen compared with heifers grazing monoculture grass pastures. Heifer hip height and fecal egg counts were not affected by treatment. These results show that the addition of BFT to organic pasture improves growth of grazing replacement heifers. Economic analyses also demonstrate that interseeding grass pastures with BFT results in an increased economic return compared with grazing monoculture grass pastures. Grass pastures interseeded with BFT may be a sustainable option to achieve adequate growth of Jersey heifers raised in an organic pasture scenario in a temperate climate. [ABSTRACT FROM AUTHOR]

Low dietary energy and decreased intake of herbage have been attributed to the reduced performance of grazing dairy cattle. We hypothesized that grasses with inherently greater energy would interact in a complementary way with condensed tannins (CT) in birdsfoot trefoil to increase herbage intake by grazing dairy heifers. Eight pasture treatments comprising high-sugar perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), and tall fescue [ Schendonorus arundinaceus (Schreb.) Dumort] were established in Lewiston, Utah as monocultures and binary mixtures with birdsfoot trefoil (Lotus corniculatus L.; BFT). Pasture treatments were rotationally stocked by Jersey heifers for 105 d in 2017 and 2018, and herbage samples were collected pre- and postgrazing for each 7-d grazing period and analyzed for herbage mass, nutritive value, and apparent herbage intake. We observed differences among pasture treatments in herbage quantity and nutritive value, as well as differences in herbage intake by grazing Jersey heifers. On average, grass-BFT mixtures had greater herbage intake than grass monocultures, and every grass-BFT treatment individually had greater herbage intake than their respective grass monocultures. Using multivariate analyses, we determined that approximately 50% of the variation in herbage intake was due to nutritive and physical herbage characteristics, with the most explanatory being characteristics related to fiber and energy, followed by those related to the percent of BFT in the herbage. Grass monocultures exhibited a range of inherent dietary energy, but there was indication that an imbalance of energy to crude protein (e.g., protein deficient) reduced intake of grass monocultures. Moreover, there was some evidence of a complementary effect between increased dietary energy and CT; however, low CT levels made it impossible to determine the effect of CT on herbage intake per se. This study confirmed that chemical and physical characteristics inherent to different pasture species have a large effect on herbage intake by grazing cattle. Pastures planted to binary mixtures of nutritious grasses and birdsfoot trefoil increase herbage intake of temperate pastures by grazing Jersey heifers. [ABSTRACT FROM AUTHOR]

Many agricultural lands in the western United States consist of soil with high concentrations of salt, which is detrimental to alfalfa ( L.) growth and production, especially in the region where water resource is limited. Developing alfalfa varieties with salt tolerance is imperative for sustainable production under increasing soil salinity. In the present study, we used advanced alfalfa breeding populations and evaluated five traits related to salt tolerance including biomass dry weight (DW) and fresh weight (FW), plant height (PH), leaf relative water content (RWC), and stomatal conductance (SC) under control and salt stress. Stress susceptibility index (SSI) of each trait and single-nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS) were used for genome-wide association studies (GWAS) to identify loci associated with salt tolerance. A total of 53 significant SNPs associated with salt tolerance were identified and they were located at 49 loci through eight chromosomes. A Basic Local Alignment Search Tool (BLAST) search of the regions surrounding the SNPs revealed 21 putative candidate genes associated with salt tolerance. The genetic architecture for traits related to salt tolerance characterized in this report could help in understanding the genetic mechanism by which salt stress affects plant growth and production in alfalfa. The markers and candidate genes identified in the present study would be useful for marker-assisted selection (MAS) in breeding salt-tolerant alfalfa after validation of the markers., (Copyright © 2019 Crop Science Society of America.)

Alfalfa (Medicago sativa L.) is a major forage crop worldwide that is relatively sensitive to soil salinity. Improved cultivars with high production on saline soil will benefit many producers and land managers. This study reports the characterization of physiological responses of two unrelated experimental alfalfa half-sib families, HS-A and HS-B, selected for their improved survival under saline conditions (up to EC 18). Six-week-old plants were subjected to NaCl-nutrient solution treatment for three weeks starting at an electrical conductivity (EC) of 3 dS m(-1) with incremental increases of 3 dS m(-1) every week, reaching 9 dS m(-1) in the third week. HS-B showed greater leaf number (72%) and stem length (44%) while HS-A showed better leaf production (84%) under salt treatment compared to the initial genetic backgrounds from which they were developed. This improved growth is associated with 208% and 78% greater accumulation of chlorophyll content in HS-B and HS-A, respectively. Both HS-A and HS-B also showed improved capability to maintain water content (RWC) under salt stress compared to the initial populations. Differing from its initial populations (P-B), HS-B did not accumulate Na in shoots after salt treatment. HS-B also maintained K(+)/Na(+) and Ca(2+)/Na(+) ratios, while P-B showed 59% and 69% decrease in these ion ratios, respectively. Na(+) content in HS-A was not different from its initial populations (P-A) after salt treatment. However, HS-A showed an enhanced accumulation of Ca(2+) and maintained the levels of Mg(2+) and K(+) in shoots compared to the P-A populations. This study provides physiological support of improved salt tolerance in HS-A and HS-B and suggests that these plants maintain ion homeostasis but have different mechanisms of coping with high salinity., (Published by Elsevier Masson SAS.)