scholarly journals Genetic and functional variation across regional and local scales is associated with climate in a foundational prairie grass

2020 ◽  
Vol 227 (2) ◽  
pp. 352-364 ◽  
Author(s):  
Ava M. Hoffman ◽  
Julie A. Bushey ◽  
Troy W. Ocheltree ◽  
Melinda D. Smith
Author(s):  
J.F.L. Charlton ◽  
A.V. Stewart

In recent years, the number of pasture species and cultivars commercially available to farmers in New Zealand has increased significantly. Reasons for this include increased commercial activity in the development and supply of proprietary cultivars, and more specialisation in New Zealand's pastoral agriculture. In particular, pasture cultivars are increasingly marketed as proprietary products with associated technical support. This year there are 109 certified cultivars available, belonging to 23 grass, legume and herb species. As a result, farmers are now able to develop improved pasture feed supply, but they are somewhat confused about pasture species and cultivars, and this frustrates their aims to produce high quality animal products from productive pastures. Accordingly, the herbage seeds industry needs to work from a clear reference list, to avoid any confusion when supplying farmers and overseas clients with their seed requirements. Our list of pasture species, types and cultivars available within New Zealand aims to be that reference. Keywords: birdsfoot trefoil, brome grass, caucasian clover, chicory, clover, cocksfoot, cultivars, herbs, lotus, lucerne, pasture, phalaris, plantain, prairie grass, red clover, ryegrass, seeds, species, strawberry clover, sub clover, tall fescue, timothy, types, white clover, Yorkshire fog


Author(s):  
G.J.Rys I.M. Ritchie ◽  
R.G. Smith ◽  
N.A. Thomson ◽  
G. Crouchley ◽  
W. Stiefel

The performance of 'Grasslands Matua' prairie grass (Bromus catharticus) was compared with perennial ryegrasses under mowing or grazing in three trials conducted in the southern North Island. Production of Matua under mowing at Flock House and Waimate West was 13% and 19% greater than G.4708 and Nui ryegrass, respectively, with the extra production contributed in summer and winter. At Masterton no difference between Matua and Ariki ryegrass production occurred under grazing. A 31% increase in annual production was recorded for both Matua and G.4708 swards receiving N, compared with those sown with white clover, with the annual yield of G.4708 receiving N similar to Matua receiving no N. Less frequent defoliation increased production of Matua swards by 17% and the Matua component by 38%. Production of Nui in comparison with Matua swards was 14% lower under frequent and 9% lower under infrequent defoliation. Similar production was recorded from red clover under frequent, and infrequent defoliation for both Nui and Matua swards. A 48% lower yield of white clover occurred under infrequent defoliation of Matua swards. At Masterton a higher incidence of goitre in newborn lambs, accompanied by a 12% lower lamb liveweight at weaning, occurred on Matua- compared with Ariki-based swards. Aspects of seasonal production, fertility response, management, and animal health are discussed.


Author(s):  
J.A. Lancashire ◽  
J.L. Brock

Some characteristics of seed quality, establishment rates, performance in mixtures and response to grazing management of 5 new pasture plants with potential in dryland are described. On a dry hill country site in the Wairarapa, the contribution of the sown grasses established in separate plots with clovers under rotational grazing was 'Grasslands Wana' cocksfoot 65%; 'Grasslands Maru' phalaris 23%; 'Grasslands Matua' prairie grass 22%; and 'Grasslands Roa' tall fescue 13% after 2 years. The other main grass species was resident perennial ryegrass which established from buried seed (ca. 240 plants/m*) and had a major impact on the establishment and growth of the sown grasses. On a seasonally dry Manawatu flat land soil 3 grazing managementsviz. set stocked all year (S); rotational all year (R); and combination (Cl (set stocked from lambing to drafting and rotational for the remainder of the year) were applied to mixtures of the new cultivars (except that 'Grasslands Apanui' cocksfoot replaced Wana) with ryegrass and white clover stocked at 20 sheep/ha. After 3 years the contribution of the new cultivars was negligible under S and ryegrass was dominant. The R pastures became cocksfoot dominant and Matua (in winter) and chicory (in summer) contributed more than in the S system. The C system produced the most evenly balanced species contribution with only Roa remaining at (5%. A sub-trial with cocksfoot cultivars demonstrated that Wana maintained better production and tiller density ~ll,000/m2 ) than Apanui (1000/m' ) under set stocking IS). Although some of the new cultivars will require specialised management procedures to fulfil their potential in dryland, the increasing and widespread use of Matua prairie grass in farming suggests that these techniques can be adopted in commercial agriculture provided good technical information is available in a management package when the cultivar is released. Keywords: Dryland, grazing management, mixtures, Matua prairie grass, Wana cocksfoot, Roa tall fescue, Maru phalaris, Chicory


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 450e-451
Author(s):  
Virginia A. Gaynor ◽  
Mary Hockenberry Meyer

There is great interest in prairie gardens and prairie restorations in the central United States. Small prairie gardens are often established with plugs, but most restorationists and landscape contractors use seed for large plantings. If initial establishment is poor, restorations are often interseeded the second or third season. However, to evaluate early establishment and determine if interseeding is necessary, contractors must be able to identify native grasses in the seedling and juvenile stages. In this study we investigated vegetative characteristics of native prairie grass seedlings. Seven species of native prairie grass were grown in the greenhouse: Andropogon gerardii (big bluestem), Sorghastrum nutans (Indian grass), Panicum virgatum (switch grass), Schizachyrium scoparium (little bluestem), Bouteloua curtipendula (sideoats grama), Elymus canadensis (Canada wildrye), and Bromus kalmii (Kalmís brome). Every 2 to 3 weeks after germination, seedlings were photographed, pressed, and mounted. Additional photographs were taken through the dissecting scope at key stages of development. Ligules and auricles were found to be useful in distinguishing species, and our close-up photographs highlight these structures. Hairiness and color were variable within a species and could not be used reliably in identification. A seedling identification key will be presented for the species studied.


Author(s):  
Martin Haspelmath

This book examines the connections between the formal and functional (semantic and syntactic) properties of indefinite pronouns. It considers the main theoretical debates surrounding the semantic and syntactic properties of indefinite pronouns as well as the diachronic sources of the markers of indefinite pronouns. It describes the new generalizations that emerge from the typological and diachronic research and provides explanations. It also outlines the goals and methods of the typological approach, focusing on the important preconditions for typology such as the availability of data from a variety of languages. Other topics covered by the book include the space of formal and functional variation found in indefinite pronouns, implicational universals, theoretical approaches to the functions of indefinite pronouns such as the tradition of structuralist semantics, the grammaticalization of indefinite pronouns, further sources of indefinite pronouns that cannot be easily subsumed under grammaticalization, and the cross-linguistic patterning of negative indefinite pronouns.


In the large body of literature on ecological and evolutionary mechanisms underlying transitions between planktotrophy and lecithotrophy, the focus has typically covered long evolutionary timescales; that is, evolution of complex larval traits is generally discussed in the context of phylogenetic patterns detectable at the level of families, classes, or phyla. An analytical approach incorporating comparative phylogenetics is increasingly used to address these long-view questions. Here, we discuss what has been learned from taking a comparative phylogenetic approach and the limitations of this approach. We propose that approaches based on a closer view—that is, analyses that focus on genetic, morphological, and functional variation among individuals, populations, or closely related congeners—have greater potential to answer questions about mechanisms underlying the loss and regain of major complex characters such as feeding larvae.


Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 595-608 ◽  
Author(s):  
Jody Hey ◽  
Richard M Kliman

AbstractIn Drosophila, as in many organisms, natural selection leads to high levels of codon bias in genes that are highly expressed. Thus codon bias is an indicator of the intensity of one kind of selection that is experienced by genes and can be used to assess the impact of other genomic factors on natural selection. Among 13,000 genes in the Drosophila genome, codon bias has a slight positive, and strongly significant, association with recombination—as expected if recombination allows natural selection to act more efficiently when multiple linked sites segregate functional variation. The same reasoning leads to the expectation that the efficiency of selection, and thus average codon bias, should decline with gene density. However, this prediction is not confirmed. Levels of codon bias and gene expression are highest for those genes in an intermediate range of gene density, a pattern that may be the result of a tradeoff between the advantages for gene expression of close gene spacing and disadvantages arising from regulatory conflicts among tightly packed genes. These factors appear to overlay the more subtle effect of linkage among selected sites that gives rise to the association between recombination rate and codon bias.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shan-Shan Zhou ◽  
Xue-Mei Yan ◽  
Kai-Fu Zhang ◽  
Hui Liu ◽  
Jie Xu ◽  
...  

AbstractLTR retrotransposons (LTR-RTs) are ubiquitous and represent the dominant repeat element in plant genomes, playing important roles in functional variation, genome plasticity and evolution. With the advent of new sequencing technologies, a growing number of whole-genome sequences have been made publicly available, making it possible to carry out systematic analyses of LTR-RTs. However, a comprehensive and unified annotation of LTR-RTs in plant groups is still lacking. Here, we constructed a plant intact LTR-RTs dataset, which is designed to classify and annotate intact LTR-RTs with a standardized procedure. The dataset currently comprises a total of 2,593,685 intact LTR-RTs from genomes of 300 plant species representing 93 families of 46 orders. The dataset is accompanied by sequence, diverse structural and functional annotation, age determination and classification information associated with the LTR-RTs. This dataset will contribute valuable resources for investigating the evolutionary dynamics and functional implications of LTR-RTs in plant genomes.


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