大豆田苣荬菜综合防除技术研究

提出了大豆田恶性杂草—苣荬菜的综合防除技术体系：１）降低大豆在整个轮作体系中的比例，将苣荬菜消灭于禾谷类作物四；２）深翻抑制芽根的萌发；３）大豆前茬作物收获后秋季茎叶处理２．４－Ｄ丁酯，最佳用药量为０．８１～１．３５ｋｇ／ｈｍ２，最佳施药时期为１０月５～１０日；４）作为挽救措施可在大豆播后苗前施２．４—Ｄ丁酯，用药量为０．７２ｋｇ／ｈｍ２，并可与乙草胺、赛克津等常规大豆田除草剂混用．     

宿根花卉的特点及其在园林中的配置

根据宿根花卉种类繁多、色彩丰富、生长稳定、抗逆性强的特点,其在园林中的配置,宜于建花坛、花境,也可群植,与背景树相结合,还可作地被植物代替草坪,也可建单类花卉园.     

SSR-based genetic linkage analysis of resistance to crown rust (Puccinia coronata f. sp. lolii) in perennial ryegrass (Lolium perenne)

Crown rust (caused by Puccinia coronata f. sp. lolii) is a serious foliar disease of the pasture and turfgrass perennial ryegrass (Lolium perenne). Previous genetic studies have detected both qualitative and quantitative resistance mechanisms, and interpretation of the genetic system is complicated by variation within the sexually reproducing pathogen. Resistant and susceptible parental genotypes of ryegrass were identified using a composite urediniospore population collected from three geographically distinct locations. A two-way pseudo-testcross mapping population was obtained as the F₁ progeny of the pair-cross between ryegrass parental genotypes Vedette₆ and Victorian₉. Both parents showed intermediate resistance against a pathogen population collected in a single geographical zone (Hamilton, Victoria), but in the F₁ population, significant variation for a range of resistance-associated characters was detected. Statistical analysis of phenotypic data suggested a major gene effect, hence bulked segregant analysis with map-assigned simple sequence repeat (SSR) markers was used to scan the genome. A marker showing strong association with resistance was assigned to linkage group (LG) 2 of perennial ryegrass. Analysis of 11 LG2 SSR markers defined an interval between loci xlpssrh03f03 and xlpssrk02e02 as containing the gene or genes (LpPc1) conferring crown rust resistance. Resistance gene determinants were inherited from both parents, with up to 80% of the total phenotypic variation explained by markers segregating from Vedette₆ and up to 26% of the variation explained by markers segregating from Victorian₉. The two contributions together resulted in an additive increase in effect, with fully resistant individuals requiring determinants from both parents. A conserved syntenic relationship was observed with linkage group B of Avena strigosa, which is the location of a cluster of resistance genes to the oat form of crown rust. The implications of this study for marker-assisted selection of disease resistance in perennial ryegrass are discussed.     

夏季狗牙根草坪不同建植方法及秋季交播黑麦草对成坪效果的影响

以狗牙根Cynodon dactylon种子和营养体为材料，在武汉地区，对5种不同建植方法建成的草坪从盖度变化、成坪时间、均一性、建植成本及秋季交播多年生黑麦草Lolium perenne后翌年狗牙根的草坪质量等方面进行综合比较。结果表明：采用夏季建植狗牙根草坪并于秋季交播多年生黑麦草的方法来建植四季常绿草坪，狗牙根采用撒茎覆沙法效果最佳，其他方法依次为开沟埋茎法、闻铺草皮法、穴植草茎法；种子直播法在翌年需重新建坪。     

Differences in Ion Accumulation and Salt Tolerance among Glycine Accessions

Salinity reduces crop yield by limiting water uptake and causing ion‐specific stress. Soybean [Glycine max (L.) Merr.] is sensitive to soil salinity. However, there is variability among soybean genotypes and wild relatives for salt tolerance, suggesting that genetic improvement may be possible. The objective of this study was to identify differences in salt tolerance based on ion accumulation in leaves, stems and roots among accessions of four Glycine species. Four NaCl treatments, 0, 50, 75 and 100 mm , were imposed on G. max, G. soja, G. tomentella and G. argyrea accessions with different levels of salinity tolerance. Tolerant genotypes had less leaf scorch and a greater capacity to prevent Na⁺ and Cl^? transport from soil solution to stems and leaves than sensitive genotypes. Magnitude of leaf injury per unit increase in leaf Na⁺ or Cl^? concentrations was lower in tolerant than in susceptible accessions. Also, plant injury was associated more with Na⁺ rather than with Cl^? concentration in leaves. Salt‐tolerant accessions had greater leaf chlorophyll‐meter readings than sensitive genotypes at all NaCl concentrations. Glycine argyrea and G. tomentella accessions possessed higher salt tolerance than G. soja and G. max genotypes.     

Field Evaluation of Cocksfoot,Tall Fescue and Phalaris for Dry Marginal Environments of South‐Eastern Australia. 1. Establishment and Herbage Production

Newly developed candidate cultivars of cocksfoot (Dactylis glomerata L.), phalaris (Phalaris aquatica L.) and tall fescue (Festuca arundinacea Schreb. = syn. L. arundinaceum (Schreb) Darbysh.) were evaluated over four years for persistence and productivity against current commercial cultivars in small plots at five locations selected for lower and less reliable rainfall and difficult soils (low pH and high Al) in south‐eastern Australia known to be marginally too dry for these grass species. The five locations were ‐ representing summer dominant rainfall, Inverell, in northern New South Wales (NSW); ‐ representing uniform rainfall; Trungley Hall, (medium rainfall), and Beckom (lower rainfall) both in southern NSW; and; representing a winter dominant pattern ‐ Eversley, (higher rainfall), and Bealiba, (lower rainfall), in central Victoria. The objective was to determine if the new candidate cultivars were more likely to persist and to be productive than current commercial cultivars. The study showed that most phalaris and cocksfoot treatments were highly productive in high rainfall years at one or both sites in southern NSW. However, all treatments had become much less productive by the end of the experimental period due to plant loss under hot, dry conditions in the final summer. At Bealiba in central Victoria, cocksfoot was the most productive species with several cocksfoot treatments of both subsp. hispanica and subsp. glomerata still present at the final harvest despite a hot and dry final summer‐autumn. Tall fescue was the most productive species in the two higher rainfall environments (Inverell, Eversley) although most treatments of all species performed well at those sites. Continental tall fescues were more productive on average than Mediterranean tall fescues at the strongly acidic Eversley site. As a result of this work, two of the new cocksfoot candidates (Moroccan Fine and AVH48 Selection) and one of the tall fescue candidates (Summer Active 1) have been licensed for commercial development and release.     

Horse Preference,Forage Yield,and Species Persistence of 12 Perennial Cool-Season Grass Mixtures Under Horse Grazing

Cool-season grass mixtures are rarely evaluated for preference, yield, and persistence under horse grazing. The objectives of this research were to evaluate horse preference, forage yield, and persistence of cool-season grass mixtures under horse grazing. Eight commercially marketed and four experimental perennial cool-season grass mixtures were planted in 2009 in a randomized complete block with five replicates and grazed by four adult horses during 2010, 2011, and 2012. All mixtures contained four to six cool-season perennial grass species. Specie density measurements were taken in each spring and fall, and yield was mechanically measured before each grazing period. After grazing, preference was determined by visually assessing percentage of forage removal on a scale of 0 (no grazing) to 100 (100% of vegetation removed). Data were analyzed using a mixed-model analysis of variance and liner regression. Horses preferred mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy (P < .001). Horses had less preference for mixtures containing ≥30% orchardgrass (P < .001). Mixtures had similar (P = .11) forage yields that ranged from 6,100 to 7,082 kg ha⁻¹. After 2 years of grazing, orchardgrass and tall fescue increased; Kentucky bluegrass remained stable; and festulolium, meadow fescue, and perennial ryegrass had the greatest rate of decline in mixtures. Orchardgrass became the dominate species, regardless of initial percentage in the mixture. Mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy should be planted in midwestern US horse pastures; however, mixtures will likely transition to tall fescue and Kentucky bluegrass–dominated pastures.     

Stable resistance against the leaf miner <Emphasis Type="Italic">Leucoptera coffeella</Emphasis> expressed by genetically transformed <Emphasis Type="Italic">Coffea canephora</Emphasis> in a pluriannual field experiment in French Guiana

Summary A pluriannual field trial of transgenic clones of Coffea canephora (the Robusta coffee tree) transformed for resistance to the lepidopteran coffee leaf miner Leucoptera coffeella was installed in French Guiana. Fifty-eight transformed clones produced by transformation of the C. canephora clone 126 were planted. They were harbouring the pEF1α constitutive promoter of Arabidopsis thaliana controlling either the Bacillus thuringiensis native gene for the cry1Ac insecticidal protein (eight clones) or a synthetic cry1Ac gene (53 clones). The vectors for the transformation were a strain of the bacterium Agrobacterium tumefaciens and one of Agrobacterium rhizogenes. The transformed clones were generally independent, presenting different integration patterns of the genetic construct. Four randomly distributed groups of five plants per transformed clone were planted along with 60 untransformed control trees. Over a 4-year period after plantation six releases of L. coffeella were performed. Mines on the leaves are the marks of larvae development and were counted on plants. A majority of the independent transformed clones harbouring the synthetic gene and transformed by the strain of A. tumefaciens displayed constantly much less mines than the control, therefore expressing a stable resistance. The need for complementary research is presented.     

Growth pattern of Juncus effusus and Juncus conglomeratus in response to cutting frequency

Increasing abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in pastures and meadows in western Norway has caused reductions in forage yield and quality in recent decades. Understanding plant development and regrowth following cutting is essential in devising cost‐effective means to control rushes. In a field experiment in western Norway, we investigated development of above‐ and below‐ground fractions of rush from seedlings to three‐year‐old plants, including the impact on vigour of disturbing growth by different cutting frequencies during the period 2009–2012. Each year, the plants were exposed to one or two annual cuts or left untreated and five destructive samplings were performed from March to early December. Juncus effusus showed significantly more vigorous growth than Juncus conglomeratus in the last two years of the study period. The above‐ground:below‐ground biomass ratio of both species increased mainly in spring and early summer and was reduced in late summer and autumn. Removal of aerial shoots also reduced the below‐ground fraction of both species. One annual cut in July effectively reduced biomass production in both species by 30–82%, which was only a slightly smaller reduction than with two annual cuts, in June and August. Mechanical control measures such as cutting can thus effectively reduce rush vigour when performed late in the growing season.