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Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and mineral content are important components of forage quality in grasses. Elevated [K]/([Ca] + [Mg]) ratios (KRAT) substantially increase the risk of ...
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Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and mineral content are important components of forage quality in grasses. Elevated [K]/([Ca] + [Mg]) ratios (KRAT) substantially increase the risk of grass tetany (hypomagnesemia) in grazing animals, which is a serious problem associated with some cool-season grasses. The objectives of this study were to map and compare QTLs controlling concentrations of CP, NDF, ADF, Al, B, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Zn, and KRAT in two full-sib Leymus triticoides x (L. triticoides x L. cinereus) TTC1 and TTC2 families. Significant genetic variation and QTLs were detected for all traits, with evidence of conserved QTLs for ADF (LG1a, LG5Xm, LG7a), NDF (LG7a), Ca (LG1b), CP, (LG5Xm), KRAT (LG3b, LG6b, LG7a, LG7b), Mn (LG2b, LG3b, LG4Xm), and S (LG3a) content in both TTC1 and TTC2 families. Moreover, the direction of QTL effects was the same for 13 of the 14 homologous QTLs in both families. The TTC1 and TTC2 KRAT QTLs on LG7a and LG7b were located near markers defining homoeologous relationships between the sub-genomes of allotetraploid Leymus, suggesting possible QTL homoeology. Another 88 QTLs were unique to one family or the other, but many of these clustered in genome regions common between the two families. These results will support development of new Leymus wildrye forages and help characterize genes controlling mineral uptake and fiber synthesis.
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Exotic African warm-season forage grasses were first introduced into the Americas in the 16th century, and have become invasive in many areas. In Florida, 16 exotic grasses are considered invasive, with the majority originating in...
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Exotic African warm-season forage grasses were first introduced into the Americas in the 16th century, and have become invasive in many areas. In Florida, 16 exotic grasses are considered invasive, with the majority originating in Africa and introduced as forages. The high propensity of Africa warm-season grasses to become invasive may be related to the same characteristics that are associated with their value as forages, including adaptability to a wide range of abiotic conditions, rapid establishment, persistence in the environment with minimal husbandry, high productivity under grazing pressure, and adaptation to disturbance. The majority of African warm-season grasses in Florida reproduce vegetatively, a trait known to be associated with invasiveness, and many have been widely planted leading to high propagule pressure and opportunities to invade a variety of niches. In spite of a long history of introduction and promotion in Florida, few African forage grasses are in use today, while many have become invasive. The benefit/cost ratio appears to be tilted in the direction of environmental and economic costs, with minimal benefits. We support newly enacted restrictions on the importation of potentially invasive plants into the USA, and suggest the establishment of a more comprehensive and transparent system for tracking past and future introductions.
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Plants of the genus Cynodon were considered as weed for a long period. However, this scenario has changed when it was observed that many species could be used in forage farming and for the recovery of degraded areas. Due to the hi...
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Plants of the genus Cynodon were considered as weed for a long period. However, this scenario has changed when it was observed that many species could be used in forage farming and for the recovery of degraded areas. Due to the high expansive potential, Cynodon spp. became an option for producers and aroused interest for breeding programs, besides requiring further studies on genetic and cytogenetic variability. Research onmeiosis in Cynodon are scarce since the inflorescences are small and the standardization of the stages of spikelet collections is difficult. The aim of the present study was to evaluate the microsporogenesis, viability and morphology of the pollen grains of two accessions of Cynodon dactylon var. dactylon (L.) Pers. (2n = 4x = 36, bermudagrass) and two accessions of Cynodon nlemfuensis var. nlemfuensis Vanderyst (2n = 2x = 18, stargrass). The slides were prepared by squash technique and stained with 2% carmine propionic. For the viability analyses of pollen grains, 2% propionic carmine and Alexander's stain were used. The measurements and the morphology of the pollen grains were defined from analyses with the acetolysis technique and scanning electron microscopy. The meiosis of the four accessions/species was regular. The staining tests showed variations in the viability rate of the pollen grain between the diploid and tetraploid species, being higher among the tetraploids. The pollen grains measured 21.1 and 28.8 mu m on average for both species and were classified as oblate spheroidal, monocolpates and showed no ornamentation, such as spicules and other attachments with non-roughened, micro reticulated exine. (c) 2018 SAAB. Published by Elsevier B.V. All rights reserved.
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Tetraploid ecotypes originated from Atlantic coastal region in comparison to diploids are of large growing stature, they build looser tuft (P-0.95), fewer vegetative offshoots (P-0.99). Their leaves are coarser (P-0.99), culms are...
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Tetraploid ecotypes originated from Atlantic coastal region in comparison to diploids are of large growing stature, they build looser tuft (P-0.95), fewer vegetative offshoots (P-0.99). Their leaves are coarser (P-0.99), culms are thicker (N.S.), less foliaged (P-0.99), the thousand-seed-weight is higher (P-0.99). They are in heading time earlier, generally more productive, the forage quality is good. From diploid subspecies, it is the ssp. aschersoniana, which adapted to the climatic condition of central Europe best and meets the requirements of herbage production. Ssp. galiciana proved to be also a high yielding grass, possessing higher resistance against rust, mildew, and good resistance against fusarioses. Ssp. lusitanica has smoother leaves, but it is less yielding, leaves proportion in herbage is lower, and shows lower winter hardness. It seems to be of little interest as a genetic resource for simple forage grass breeding in this country.
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Woody species can exert positive, neutral or negative influence on the growth of neighbouring grass species. The objective of this work was to assess the impact of woody species (Prosopis caldenia and Larrea divaricata) on abovegr...
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Woody species can exert positive, neutral or negative influence on the growth of neighbouring grass species. The objective of this work was to assess the impact of woody species (Prosopis caldenia and Larrea divaricata) on aboveground biomass production and quality of perennial grasses (Piptochaetium napostaense and Nassella clarazii). Overall, aboveground biomass production of P. napostaense was higher in the area of influence of L. divaricata while that of N. clarazii was higher in the area of influence of P. caldenia. In general, P. napostaense showed higher, while N. clarazii showed lower, values of aboveground biomass production when beneath the canopy of each woody species. At the end of the vegetative growing period, crude protein content (CP) of grass species was lower beneath the canopy of woody species than in open areas; the only exception being N. clarazii in the area of influence of P. caldenia where no differences were found. No differences were found in CP content between any of the experimental locations at the end of the reproductive growing period. In general, in vitro digestibility was lower within the area of influence of P. caldenia than of L. divaricata for both growing periods. The results of the present study suggest that the impact of woody species on aboveground biomass production and quality are species-specific in semi-arid rangelands of central Argentina and highlight the need of further research in order to prescribe sound and generalized shrub management policies.
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Hypsodont (i.e. high-crowned) teeth have been interpreted as an indicator of feeding preferences and habitat selection in ungulates. For this reason, the degree of hypsodonty has been used for estimating the diet of ancient taxa a...
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Hypsodont (i.e. high-crowned) teeth have been interpreted as an indicator of feeding preferences and habitat selection in ungulates. For this reason, the degree of hypsodonty has been used for estimating the diet of ancient taxa and in palaeoenvironmental reconstructions. The goal of this study is to elucidate the relative importance of grass consumption and open habitat foraging in the development of hypsodont teeth, using novel computer techniques of knowledge discovery applied to a dataset of 134 species of artiodactyls and perissodactyls distributed among thirteen families. The results obtained suggest that high-crowned teeth represent an adaptation for feeding in an open habitat, although the minimum threshold of hypsodonty seems to increase with the relative length of the anterior part of the jaw. On the contrary, there is no direct relationship between the degree of hypsodonty and the percentage of grass consumed, except for the correspondence between grazing and dwelling in open habitats. A relatively wide muzzle evidences an adaptation for grass foraging in open and mixed habitats, but there are some non-grazing species from a closed habitat that also show wide muzzles. Thus, the hypsodonty index, combined with the length of the anterior part of the jaw and the width of the muzzle, allows accurate inferences on the ecological preferences of extinct ungulates.
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The soil flood tolerance of seven genotypes of Panicum maximum Jacq. (PM11, PM34, PM40 and PM45, and the commercial cultivars Massai, Mombaca and Tanzania) was evaluated in plants subjected to two conditions: flooded and not flood...
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The soil flood tolerance of seven genotypes of Panicum maximum Jacq. (PM11, PM34, PM40 and PM45, and the commercial cultivars Massai, Mombaca and Tanzania) was evaluated in plants subjected to two conditions: flooded and not flooded, during a period of 14 days. Flooding significantly decreased the total and above ground biomass of PM40 and PM45. For cultivar Tanzania, flooding decreased these two variables and also root biomass. The root, total and above ground relative growth rates were significantly reduced by flooding in cultivar Tanzania, while in PM45 only the above ground relative growth rate was reduced. Cultivar Tanzania showed significant differences for all variables analyzed, thus was not flood tolerant, as well as PM40 and PM45. It could be concluded that Massai, PM34, Mombaca and PM11 were the most flood tolerant genotypes.
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Groundwater depletion is one of the most pressing issues facing the dairy industry in arid regions. One strategy to improve the industry's drought resilience involves feeding drought-tolerant forage crops in place of traditional f...
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Groundwater depletion is one of the most pressing issues facing the dairy industry in arid regions. One strategy to improve the industry's drought resilience involves feeding drought-tolerant forage crops in place of traditional forage crops such as alfalfa and corn silage. The objective of this study was to assess the productivity of lactating dairy cows fed diets with teff hay (Eragrostis tef) as the sole forage. Teff is a warm-season annual grass native to Ethiopia that is well adapted to drought conditions. Nine multiparous Holstein cows (185 +/- 31 d in milk; mean +/- standard deviation) were randomly assigned to 1 of 3 diets in a 3 x 3 Latin square design with 18-d periods (14 d acclimation and 4 d sampling). Diets were either control, where dietary forage consisted of a combination of corn silage, alfalfa hay, and native grass hay, or 1 of 2 teff diets (teff-A and teff-B), where teff hay [13.97 +/- 0.32% crude protein, dry matter (DM) basis] was the sole forage. All 3 diets were formulated for similar DM, crude protein, and nonfiber carbohydrate concentrations. Control and teff-A were matched for concentrations of neutral detergent fiber (NDF) from forage (18.2 +/- 0.15% of DM), and teff-B included slightly less, providing 16.6% NDF from forage. Dry matter intake, milk and component production, body weight, body condition score, as well as DM and NDF digestibility were monitored and assessed using mixed model analysis, with significance declared at P < 0.05. Treatment had no effect on dry matter intake (28.1 +/- 0.75 kg/d). Similarly, treatment had no effect on milk production (40.7 +/- 1.8 kg/d). Concentrations of milk fat (3.90 +/- 0.16%) and lactose (4.68 +/- 0.07%) were also unaffected by treatment. Teff-A and teff-B increased milk protein concentration compared with the control (3.07 vs. 3.16 +/- 0.09%). Treatment had no effect on energy-corrected milk yield (43.4 +/- 1.3 kg/d), body weight, or body condition score change. Additionally, treatment had no effect on total-tract DM or NDF digestibility. Results from this study indicate that teff hay has potential to replace alfalfa and corn silage in the diets of lactating dairy cattle without loss of productivity.
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This study determined the number of spittlebug adults, Mahanarva spectabilis Distant (Hemiptera: Cercopidae), that should be used in selection tests of the forage grass, Brachiaria ruziziensis (Germain and Evrard). In this study, ...
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This study determined the number of spittlebug adults, Mahanarva spectabilis Distant (Hemiptera: Cercopidae), that should be used in selection tests of the forage grass, Brachiaria ruziziensis (Germain and Evrard). In this study, 0, 1, 2, 4, or 8 M. spectabilis adults were kept in plants for 4 or 8 d per experimental plot. After these periods, the insects were removed from the plants and chlorophyll content, damage score, dry weight, fresh weight, and percent dry matter of shoots were evaluated. Chlorophyll content decreased significantly with higher density of M. spectabilis in plants exposed to the pest for 4 or 8 d. Plants that were exposed to eight spittlebugs for 8 d showed a ≈60% loss of chlorophyll content. When the forage was infested with eight adults for 4 d, the average damage score was 3 (50% of the leaf area was affected). The damage score and fresh and dry weights of the forage did not change depending on the exposure time of the plants to the spittlebugs. The percentage of dry matter of the plants infested was higher with the increase insect density and exposure time for all densities. Thus, the minimum recommended number is eight M. spectabilis adults for 4 d in resistance tests of B. ruziziensis to this pest species.
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