安徽省玉米主要害虫种类与发生为害初探

系统调查了安徽省不同地区、玉米不同生育期害虫种类及发生为害情况。调查发现:安徽省全境玉米适生期长,玉米种植结构复杂,北部地区以连片种植夏玉米为主,南部地区以插花式播种春玉米为主。与为害夏玉米的害虫相比,南部春玉米害虫种类更为多样。亚洲玉米螟Ostrinia furnacalis(Guenée)是全省玉米的主要害虫,其中铜陵地区春玉米苗期受亚洲玉米螟为害最重,被害株率达25.6%。蜗牛在夏玉米穗期和春玉米苗期为害严重,部分田块被害株率达100%。桃蛀螟Conogethes punctiferalis(Guenée)是春、夏玉米穗期的另一主要害虫,常与亚洲玉米螟、棉铃虫Helicoverpa armigera(Hübner)和黏虫Mythimna separata(Walker)混合发生,但在淮北地区玉米秸秆中未发现冬后存活的桃蛀螟幼虫。     

两种轮作模式下垄沟覆膜夏玉米适播密度的研究

为确定基于垄沟集雨覆膜栽培的冬油菜-夏玉米和冬小麦-夏玉米2种轮作模式下夏玉米的最适播种密度,于2019年设置5月28日(B1,冬油菜-夏玉米轮作模式下夏玉米播期)和6月15日(B2,冬小麦-夏玉米轮作模式下夏玉米播期)2个播期,每个播期均设置平作不覆盖5万株·hm-2(CK)、垄沟覆膜5万株·hm-2(M1)、垄沟覆...     

辽西不同玉米/沙打旺间作模式的土壤水分和产量效应研究

以玉米清种、沙打旺清种、玉米/沙打旺间作(2∶1)、玉米/沙打旺间作(4∶2)、玉米/沙打旺间作(2∶2)为例研究不同间作模式的土壤水分和产量效应。结果表明:玉米/沙打旺间作对土壤水分时空变化有一定的影响,土壤水分季节性变化趋势明显,从上到下,随土层深度增加,土壤含水量均表现出"先增大,后减小"的趋势。玉米/沙打旺间作对玉米株高的影响不显著,而对沙打旺的株高影响显著,同时株高的差异改变了玉米的通风透光状况。玉米、沙打旺间作(4∶2)可以影响玉米干物质积累速率并延长峰值出现的时间,使其保持较长的快速增长期。玉米产量性状中,穗长、穗粗、行粒数、行数和轴粗各处理间差异不显著,而百粒重达到了显著性差异,产量也达到了极显著差异,以玉米清种最大,为15 567.50 kg/hm2,以玉米/沙打旺(2∶1)的产量最低,为11 238.33 kg/hm2。综合来看,玉米/沙打旺间作(4∶2)模式可以在辽西地区推广种植。     

不同耐旱性玉米初生根和次生根中铁、锰、铜、锌、钠含量分析

以生长于田间的玉米掖单13(耐旱性玉米)和丹玉13(不耐旱性玉米)为试验材料,应用ICP对供试玉米的初生根和第一、二、三、四、五、六、七、八和第九层次生根的铁、锰、铜、锌和钠元素含量等项指标进行了测定和比较分析。结果表明:除个别根外,耐旱性玉米不同类型根中的铜含量极显著高于不耐旱性玉米根系(P0.01);根中的锰元素含量和锌元素含量极显著高于不耐旱性玉米根系(P0.05);根系中铁元素含量和根系中的钠元素含量在两品种玉米根系之间差异未达显著水平(P0.05)。     

施氮量和耕作方式对春玉米产量和土体硝态氮累积的影响

在冀西北春玉米种植区,对不同施氮量和耕作方武春玉米产量和土体硝态氮累积状况进行研究分析,结果表明,和常规耕作相比,免耕对春玉米产量无明显影响,通过建立的施氮量和春玉米产量的肥料效应函数,求得免耕1(玉米和大豆间作)、免耕2(玉米单作)和常规耕作(玉米单作)3种处理的适宜氮推荐用量分别为192～209 kg/hm2、19...     

重组酶聚合酶扩增技术(RPA)快速检测玉米褪绿斑驳病毒

玉米褪绿斑驳病毒(maize chlorotic mottle virus,MCMV)是我国颁布的一种禁止进境的检疫性有害生物,自然寄主有玉米、小麦、黍、大麦等。自然情况下,MCMV常与甘蔗花叶病毒(sugarcane mosaic virus,SCMV)、玉米矮花叶病毒(maize dwarf mosaic virus,MDMV)、小麦线条花叶病毒(wheat streak mosaic virus,WSMV)共同侵染玉米,可造成玉米产量损失高达10%~90%(Hilker et al.,2017)。     

不同耐旱基因型玉米根系大量元素含量分析

以生长于田间的玉米掖单13(耐旱基因型玉米)和丹玉13(不耐旱基因型玉米)为试验材料,应用ICP对供试玉米的初生根和第一、二、三、四、五、六、七、八和第九层次生根的大量元素氮、磷、钾、钙和镁等项指标进行了测定和比较分析.结果表明:除个别根外,耐旱基因型玉米不同类型根中的全氮含量和速效氮含量极显著低于不耐旱基因型玉米根系(P<0.01);根中的钙元素含量和镁元素含量极显著高于不耐旱基因型玉米根系(P<0.01);根系中磷元素含量和根系中的钾元素含量在两基因型玉米根系之间差异不显著(P＞0.05).     

玉米细菌性枯萎病菌接种玉米方法的比较

由Erwinia stewartii(Smith)Dye引起的玉米细菌性枯萎病造成玉米作物经济上的损失。这个病害是以在春玉米上(主要在甜玉米上)幼苗的萎蔫型为特征,而后期的枯萎型在马齿玉米上有日益增加其重要性的趋势,特别沿南部玉米带的北缘,在玉米跳(虫甲)(Chaetocnema pulicaria Melsk.)     

玉米螟为害玉米的产量损失估计及单株允许残留虫量

为探明亚洲玉米螟为害春、秋玉米的产量损失,于1990年始在浙江东阳玉米研究所采用田间自然种群为害与在玉米不同生育期采取药剂控制使害虫造成一定梯度相结合的方法,研究螟害对产量损失的影响。结果获得螟害对产量损失的两个曲线方程: 春玉米:Y_1=1-[0.67 (1-0.67)×0.7558~(P 0.7)] 秋玉米:Y_2=1-[0.70 (1-0.70)×0.7767~(P 1)] P为单株玉米上平均虫量,0.7和1为最后单株玉米上允许的残留虫量(包含蛀孔),损失率分别为5.9％、6.7％。     

长岭县不同降水年型玉米需水规律研究

在长岭县开展玉米大田试验,探讨在相同的土壤及农田管理条件下,不同降水年型（丰水年、平水年、枯水年和极枯水年）玉米生长需水及水分来源的变化规律。结果表明：玉米生长过程中各个阶段需水量不同,中期最大,初期和后期较小;2007年(极枯水年)玉米生长需水量最大(460.2 mm),2006年(枯水年)次之(423.8 mm),2008年(平水年)再次之(393.5 mm),2005年(丰水年)最小(342 mm),越是干旱的年份玉米生长需水量和单位质量玉米生长需水量越大;丰水年玉米生长需水量与有效降水量的耦合度最高,平水年次之,枯水年再次之,极枯水年最低;2005—2008年土壤水消耗量依次为79.8 mm、199.1 mm、222.7 mm和104.6 mm,越是干旱的年份土壤水消耗量越大;玉米生长过程中7月和8月土壤水消耗量较大,应适当增加灌溉。     

鲁豫皖交界地区四个小麦禾谷孢囊线虫群体致病型鉴定

为了明确鲁豫皖交界地区小麦禾谷孢囊线虫的致病类型,利用23个国际鉴别寄主品种和1个当地小麦品种温麦19对采自山东菏泽、安徽颍上、河南商丘和淮阳的4个小麦禾谷孢囊线虫群体致病型进行了鉴定。4个群体的致病型不同于国际上已命名的16个小麦禾谷孢囊线虫致病型。13个A组鉴别寄主对山东菏泽与安徽颍上群体具有相同的抗性反应,这2个线虫群体属于同一致病型;河南商丘群体与上述2个群体的毒性相似,但大麦寄主KVL191对山东菏泽群体和安徽颍上群体表现为抗病,而对河南商丘群体表现感病;河南淮阳群体的致病谱较宽,明显不同于其它3个群体。对照小麦品种温麦19对4个小麦禾谷孢囊线虫群体均表现感病。     

Characterization of virulence reactions for Heterodera avenae populations from two localities in Algeria

Heterodera avenae is widely distributed in areas where most cereal crops are produced in Algeria. However, the virulence of the Algerian populations of this nematode on individual cereal species and cultivars has not been well documented. The virulence of H. avenae populations from Tiaret and from Oued Smar were tested under natural outdoor conditions and in an in vitro test to determine reactions of nine barley, oat and wheat cultivars selected from the International differential assortment for identifying pathotypes of H. avenae. All nine cereal differentials expressed the same reactions to both populations. The nematodes reproduced well on the barley cultivar ‘Emir’ and the wheat cultivar ‘Capa’. Resistant entries included the barley cultivars ‘Siri’, ‘Ortolan’ and ‘Morocco’, the oat cultivars ‘Nidar II’ and ‘A. sterilis I.376’, and the wheat cultivars ‘Loros’ and ‘AUS10894’. This matrix of reactions indicated that H. avenae populations from both locations were characterized as H. avenae Group 1 pathotypes but did not conclusively distinguish among pathotypes Ha21, Ha31 or Ha81. The Cre1 gene was identified as a potentially valuable source of resistance when developing wheat cultivars intended for release into these localities.     

Breeding spring wheat for improved allelopathic potential

It is becoming apparent that allelopathy plays a significant role in the competitive ability of cereals against weeds; barley, wheat and rice cultivars with high allelopathic activity have been identified. However, direct breeding efforts to improve allelopathy have to date only been reported in rice. In this study, a breeding programme in spring wheat ( Triticum aestivum ) was evaluated to determine the efficiency of selection of allelopathy and the ability of breeding lines to suppress weeds in the field. The material used originated from a cross between a Swedish cultivar with low allelopathic activity and a Tunisian cultivar with high allelopathic activity. Allelopathic activity was measured as growth inhibition of perennial ryegrass ( Lolium perenne ) roots when grown together with the wheat cultivars on agar. For screening of F₂ populations, a single plant bioassay was used for the first time. In the F₆ and F₇ generations, three breeding lines with an average improved allelopathy of 20% and one line with an unimproved allelopathy activity, but with the same phenotype as the high allelopathic lines, were tested together with the low allelopathic Swedish parent. The main result from the field study was a 19% average reduction of weed biomass for the high allelopathic lines, but no significant reduction of the low allelopathic breeding line. Early shoot length and early crop biomass (stages 37–39, Zadoks scale) and straw length of the high allelopathic lines were not significantly different from the Swedish parent. A negative effect was that grain yield was reduced by 9% in the high allelopathic lines. It is suggested that the reduced biomass of weeds in plots planted with the highly allelopathic wheat lines is related to differences in allelopathic activity and not differences in plant growth.     

Genetic relationships among populations of Gibberella zeae from barley, wheat, potato, and sugar beet in the upper Midwest of the United States

Gibberella zeae, a causal agent of Fusarium head blight (FHB) in wheat and barley, is one of the most economically harmful pathogens of cereals in the United States. In recent years, the known host range of G. zeae has also expanded to noncereal crops. However, there is a lack of information on the population genetic structure of G. zeae associated with noncereal crops and across wheat cultivars. To test the hypothesis that G. zeae populations sampled from barley, wheat, potato, and sugar beet in the Upper Midwest of the United States are not mixtures of species or G. zeae clades, we analyzed sequence data of G. zeae, and confirmed that all populations studied were present in the same clade of G. zeae. Ten variable number tandem repeat (VNTR) markers were used to determine the genetic structure of G. zeae from the four crop populations. To examine the effect of wheat cultivars on the pathogen populations, 227 strains were sampled from 10 subpopulations according to wheat cultivar types. The VNTR markers also were used to analyze the genetic structure of these subpopulations. In all populations, gene (H = 0.453 to 0.612) and genotype diversity (GD = or >0.984) were high. There was little or no indication of linkage disequilibrium (LD) in all G. zeae populations and subpopulations. In addition, high gene flow (Nm) values were observed between cereal and noncereal populations (Nm = 10.69) and between FHB resistant and susceptible wheat cultivar subpopulations (Nm = 16.072), suggesting low population differentiation of G. zeae in this region. Analysis of molecular variance also revealed high genetic variation (>80%) among individuals within populations and subpopulations. However, low genetic variation (<5%) was observed between cereal and noncereal populations and between resistant and susceptible wheat subpopulations. Overall, these results suggest that the populations or subpopulations are likely a single large population of G. zeae affecting crops in the upper Midwest of the United States.     

Effect of genotype unit number and spatial arrangement on severity of yellow rust in wheat cultivar mixtures

Pure stands of a yellow rust-susceptible wheat cultivar, pure stands of a resistant cultivar, and a 1 : 1 random mixture of resistant and susceptible cultivars were compared to populations in which strips or hills of the cultivars were alternated to attain genotype units (units of the same host genotype) that were larger in area than that of a single wheat plant. These four host populations were grown in plots of different sizes in order also to alter the number of units per host population. The goal was to determine if increasing the number of genotype units in mixed populations of large genotype units improved disease control relative to pure-line populations by increasing the amount of inoculum exchange among genotype units. Random mixtures of the two cultivars always provided better disease control than did alternating strips or hills. Evidence for an effect of genotype unit number on the efficacy of mixtures for rust control was found in only one of three experiments. Random mixtures of the two cultivars increased grain yield relative to the pure stand mean, but alternating strips did not.     

Heredity of Heterodera avenae Resistance Originating from two Barley Cultivars and one Spring Wheat Cultivar1

Two spring barley cultivars Bajo Aragon-1-1 and Martin 403-2 from the cyst nematode test assortment were each crossed with a susceptible, a pathotype-11 -resistant, and a pathotype-11 and 12-resistant cultivar, as well as with each other. A spring wheat cultivar, AUS 10894, from the cyst nematode test assortment was crossed with a susceptible and a resistant cultivar. From these crosses F! and F₂ single plants were tested against pathotype 12 and/or pathotype 11 of Heterodera avenae in Denmark. Some plants of the spring barley cultivar Bajo Aragon-1-1 have two resistance genes, which probably are both dominant, but it is not out of the question that one might be recessive. Each gene is inherited independently of the other or with low linkage frequency. Neither gene is the same as or allelic to the resistance gene in the cultivar Ortolan, but one gene is allelic to or the same as the 191 gene in the cultivar Siri. The spring barley cv. Martin 403-2 has one dominant resistance gene which is not allelic to or the same as the resistance gene in Ortolan but is the same as or allelic to the 191 gene in the cultivar Siri. It is possible that there is one more gene, which might be recessive against pathotype 11. The spring wheat cv. AUS 10894 has one dominant resistance gene which might be the same as or allelic to the Loros gene.     

Inheritance and molecular mapping of barley genes conferring resistance to wheat stripe rust

ABSTRACT Most barley cultivars are resistant to stripe rust of wheat that is caused by Puccinia striiformis f. sp. tritici. The barley cv. Steptoe is susceptible to all identified races of P. striiformis f. sp. hordei (PSH), the barley stripe rust pathogen, but is resistant to most P. striiformis f. sp. tritici races. To determine inheritance of the Steptoe resistance to P. striiformis f. sp. tritici, a cross was made between Steptoe and Russell, a barley cultivar susceptible to some P. striiformis f. sp. tritici races and all tested P. striiformis f. sp. hordei races. Seedlings of parents and F(1), BC(1), F(2), and F(3) progeny from the barley cross were tested with P. striiformis f. sp. tritici races PST-41 and PST-45 under controlled greenhouse conditions. Genetic analyses of infection type data showed that Steptoe had one dominant gene and one recessive gene (provisionally designated as RpstS1 and rpstS2, respectively) for resistance to races PST-41 and PST-45. Genomic DNA was extracted from the parents and 150 F(2) plants that were tested for rust reaction and grown for seed of F(3) lines. The infection type data and polymorphic markers identified using the resistance gene analog polymorphism (RGAP) technique were analyzed with the Mapmaker computer program to map the resistance genes. The dominant resistance gene in Steptoe for resistance to P. striiformis f. sp. tritici races was mapped on barley chromosome 4H using a linked microsatellite marker, HVM68. A linkage group for the dominant gene was constructed with 12 RGAP markers and the microsatellite marker. The results show that resistance in barley to the wheat stripe rust pathogen is qualitatively inherited. These genes might provide useful resistance against wheat stripe rust when introgressed into wheat from barley.     

中国条锈菌新小种条中30、31号的研究

本文报道了1991年以来对新小种条中30、31号鉴定与致病性的研究。继1991年发现对绵阳系成株小麦有致病力的、对Hybrid46有毒的新致病类型91—1,1993年又发现了新的致病类型93—1。根据它们对我国鉴别寄主的反应,命名为条中30、31号。与条中28、29号相比,新小种具有更宽毒性基因组成和更高的相对寄生适合度值,它们对我国生产品种、高代品系和重要抗源有更广的致病范围。证实两个新小种的出现和发展是绵阳系小麦抗条锈变异的主要因素,建议加强对新小种抗病育种和流行预测的研究。     

Effect of host and non‐host crops on Plasmodiophora brassicae resting spore concentrations and clubroot of canola

Plasmodiophora brassicae, causal agent of clubroot of crucifers, poses a serious threat to Canadian canola production. The effects of fallow (F) periods and bait crops (clubroot‐susceptible canola (B) and perennial ryegrass (R)) on clubroot severity and P. brassicae resting spore populations were evaluated in five sequences: R–B, B–R, R–F, B–F and F–F. Both host and non‐host bait crops reduced clubroot severity in a subsequent crop of a susceptible canola cultivar compared with fallow. Resting spore and P. brassicae DNA concentrations decreased in all treatments, but were lowest for the R–B and B–R bait crop sequences. In addition, two studies were conducted in mini‐plots under field conditions to assess the effect of rotation of susceptible or resistant canola cultivars on clubroot severity and P. brassicae resting spore populations. One study included three crops of susceptible canola compared with a 2‐year break of oat–pea, barley–pea, wheat–wheat or fallow–fallow. The other study assessed three crops of resistant canola, two crops of resistant canola with a 1‐year break, one crop of resistant canola and a 2‐year break, and a 3‐year break with barley followed by a susceptible canola. The rotations that included non‐host crops of barley, pea or oat reduced clubroot severity and resting spore concentrations, and increased yield, compared with continuous cropping of either resistant or susceptible canola. Growing of a susceptible canola cultivar contributed 23–250‐fold greater gall mass compared with resistant cultivars.     

Variation in allelopathic activity over 100 years of barley selection and breeding

Barley (Hordeum vulgare L.) landraces and cultivars from Finland, Sweden, Denmark and the Baltic states, in total 127, were analysed for allelopathic activity against ryegrass (Lolium perenne L.). The germplasm covered most of the gene pool used during 100 years of barley breeding. An agar‐based bioassay developed for screening allelopathic activity was used. In the germplasm from all countries a decreasing trend in allelopathic activity was observed with the introduction of new cultivars from 14% for the Swedish to 31% for the Finnish cultivars. In the Finnish, Swedish and Baltic cultivars an increase in root growth was noticed, and changes in root biomass therefore cannot explain the decrease in allelopathy. In fact, the allelopathic activity per milligram root decreased with 32–85%. In contrast, root growth decreased over time in the Danish collection. In the Finnish cultivars both two‐ and six‐row barley cultivars were tested with similar results. Allelopathic activity of barley probably originated from different landraces, and in most cases from a specific landrace from the Swedish island of Gotland. We suspect that more than 100 years of selection and breeding have resulted in a dilution of the genes from landraces and consequently a declining allelopathic activity. In the Swedish collection, two cultivars did not follow the general trend and in both cultivars, several landraces had been combined.