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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]

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]

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-1, ranging from not measurable to 2.96 Mg ha-1 compared to Ladak alfalfa (Medicago sativa L.) at 2.28 mg ha-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. [ABSTRACT FROM AUTHOR]

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 geno-types for their relative ability to survive under saline conditions. In 2000 and 2001, 12 affalfa (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-1 and increased 3.0 dS m-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 (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 LD50 and LD75 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. [ABSTRACT FROM AUTHOR]

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 × 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 I 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. [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]

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]