大豆锈菌冬孢子形成研究

大豆锈菌可在大豆植株上形成冬孢子和冬孢子堆，田间在10－11月初形成，但数量较少，冬孢子堆的形成与大豆品种，温度，湿度，光照等有关，日均温20度以下，日最低气温16度以下有利于冬孢子形成，昼夜温差大，形成冬孢子堆数量多，感病品种比抗病品种出现冬孢子的时间早，数量多，但体积小，冬孢子堆的大小与数量成负相关，在13－25度，200lux条件下，冬孢子堆体积较大，数量较多。     

温度对花生锈菌夏孢子萌发及侵染的影响

温度是影响锈菌夏孢子侵染花生的重要因素之一,关于温度对花生锈菌夏孢子萌发及侵染的影响鲜有报道。本研究通过不同温度条件下夏孢子的萌发率和8个对锈病抗感差异较大花生品种的接种试验确定锈孢子萌发和侵染的最适温度。研究结果表明,夏孢子萌发和侵染的适宜温度为25～28℃,此条件下夏孢子萌发率较高,为68.23%,抗病材料的潜伏期为8.11～8.67 d,感病材料的潜伏期为6.44～6.89 d。本研究可为花生种质锈病抗性鉴定和抗锈病品种选育工作提供理论依据。     

大豆锈菌在不同豆科寄主上的致病反应

本文研究了大豆锈菌在大豆、豌豆、绿豆、蚕豆、菜豆和豇豆叶片上的致病反应。接种后锈菌均能在上述植物的叶片上形成侵染病斑,病斑形成时间和形态因物种而异;锈菌在大豆和豌豆叶片上可形成孢子堆,豌豆叶片上的孢子堆能释放出具有交叉侵染能力的夏孢子;锈菌在绿豆上可形成具有突起的病斑,在其它豆科叶片上仅形成过敏型枯死病斑,不形成孢子堆。组织学观察表明：大豆和豌豆叶片上孢子堆周围组织布满菌丝,孢子堆中有不同发育阶段的夏孢子;其他豆科植物叶片上的病斑中仅含有一些细胞碎片,未见孢子堆和夏孢子形成。     

大豆疫霉根腐病菌游动孢子侵染野生大豆下胚轴的细胞学观察

用大豆疫霉根腐病菌的游动孢子悬浮液处理抗感不同野生大豆下胚轴,在接种后1.5~24 h,使用扫描电镜观察了野生大豆与大豆疫霉菌的亲和性和非亲和性互作。结果显示:接种1.5 h后游动孢子在感病野生大豆下胚轴表面产生休止孢,并产生芽管;接种3 h后休止孢萌发产生附着孢,开始侵入下胚轴表皮;接种6 h后侵入加深;接种12 h后附着孢完全进入下胚轴表皮;接种24 h后附着孢孢膜已经开始进入到表皮里。游动孢子悬浮液处理抗病野生大豆后,其侵染过程与亲和反应相似,只是游动孢子在下胚轴表皮产生芽管时间和附着孢侵入下胚轴表皮层的时间比亲和反应迟。     

云南省德宏亚热带地区冬大豆栽培中的一些技术要点

针对德宏边疆地区冬大豆种植管理水平低、单产不高这一问题,提出从品种的选择、整地质量、播期的安排、种植密度、播种方式、施肥、田间管理等几方面入手来改进栽培模式,推广规范化栽培,挖掘德宏冬大豆增产潜力。     

瓜亡革菌担孢子诱致的黄麻叶斑及单担孢子菌株在土壤中的存活期

瓜亡革菌(ThanatePhorus Cucumeris)的一个菌株在黄麻茎杆上产生其有性时期，它的担孢子能侵染诱致黄麻成株叶斑。麻苗出土前的猝倒是受土壤中菌丝体侵染后引起的。此菌在体外于100℃蒸汽处理的砂质壤土中存活期为120天，在体内于60℃蒸汽处理的砂质壤土中存活期为30天。而此菌的有些单担孢子菌核在体外的存活期可达180天，在体内的则为60天。     

微肥在大豆生产中的作用

微肥在大豆生产中的作用黑龙江省农科院大豆研究所郭玉虹在大豆的正常发育进程中，氮、磷钾元素占有重要的地位，但微量元素也是不可缺少的养分。它的生理作用是氮、磷、钾不可代替的。土壤中微量元素供给不足时，大豆会出现缺素病害，引起体内生理功能失调，导致减产，质...     

硼肥在大豆生产中的作用

硼是大豆生长发育必须的微量营养元素之一 ,用量虽小 ,但它的作用与氮、磷、钾等大量元素相比 ,却同等重要 ,这和它在大豆植株体内所担负的生理作用是密不可分的。国内外许多研究证明 ,大豆施用硼肥对促进植株生长发育、提高产量和改善品质均有明显的效果。一、硼素的作用硼虽不是大豆体的组成物质 ,但在某些生理过程中却起着特殊作用。硼有增强输导组织的作用 ,促进碳水化合物的正常运转 ,有利于蛋白质的合成和根瘤菌固氮 ;能促进花粉萌发和花粉管伸长 ,有利授精和结实。据浙江省农业科学院土肥所试验 ( 1 987-1 989年 ) ,施硼肥后 ,株高降…     

在美国爱荷华州叶面杀真菌剂对侵染Phomopsis spp．大豆的影响

2008--2009年在爱荷华州的2个地点,在大豆[Glycinemax（L．）]R3、R5和R3＋R5期进行了杀真菌剂唑菌胺酯（嗜球果伞素）和戊唑醇（苯三唑）施用试验研究,评价了大豆田间茎和种子被Phomopsis spp．侵染的发病率、产量和种子品质。结果表明,2008--2009年在R3＋R5时期和2008年在R5时期施用唑菌胺酯后,大豆茎Phomopsis spp．发病率降低,较对照未施药剂茎Phomopsis spp．发病率大约降低三分之二。     

一个大豆锈病新抗源的筛选与鉴定

采用离体叶片接种方法对2007-2010年收集的1 000份大豆种质资源进行抗性筛选,得到1份高抗材料SX6907。SX6907在接种后20d不产生侵染病斑;在高浓度锈菌接种时,产生少数红褐色RB（Red-brown）病斑,但无孢子堆破裂现象,无孢子产生;SX6907的接种表现与已知抗病品种主要表现为黄褐色TAN型感病病斑明显不同。组织学观察表明, SX6907在接种部位造成细胞坏死,侵染点无孢子形成,其抗性表现为抗锈菌侵染。SX6907是一个优异的抗锈病资源,可做亲本在抗锈病育种中应用。     

Saccharin-induced systemic acquired resistance against rust (Phakopsora pachyrhizi) infection in soybean: Effects on growth and development

We examined the effect of saccharin on the systemic acquired resistance (SAR) response of soybean to the fungus Phakopsora pachyrhizi, the causal agent of soybean rust. Plants were grown hydroponically in half-strength Hoagland’s solution and were challenged with the pathogen 1, 5, 10 and 15 d after treatment with 3 mM saccharin applied either as a foliar spray or a root drench at the 2nd trifoliate (V3) and early reproductive (R1) stages. Plants were destructively harvested and assessed for visible rust symptoms 2 wk after inoculation. Mode of saccharin application was a significant factor influencing the severity of rust infection. Saccharin applied as a root drench was more effective than the foliar spray treatment at inducing SAR, with increased resistance observed 1 d after application. Systemic protection against rust infection was still apparent 15 d after application of saccharin as a root drench. In contrast, foliar treatment with saccharin did not increase systemic protection until 15 d after treatment. When systemic protection was induced by the application of saccharin in either manner, there was no significant reduction of plant growth, except when plants were inoculated 15 d after the saccharin application as a root drench at the R1 stage of development.     

Evaluation of soybean for resistance to soybean rust in Vietnam

Soybean rust, caused by Phakopsora pachyrhizi Sydow, is a severe foliar disease of soybean [Glycine max (L.) Merr.] that occurs throughout most soybean producing regions of the world. The objective of this research was to evaluate selected soybean genotypes for resistance to soybean rust in Vietnam. Five field experiments in Vietnam were completed from 2006 to 2009. The area-under-the-disease-progress-curve (AUDPC) was calculated for each soybean genotype based on four disease assessments taken during the reproductive growth stages. AUDPC units among soybean genotypes in each experiment differed (P < 0.05). Over the five experiments, the resistant check DT 2000 was most often the genotype with the lowest AUDPC units while the sources of rust resistance (Rpp1-5) did not always have low AUDPC units in each experiment, although PI 230970 (Rpp2) appeared to be more stable. A few genotypes with non-characterized genes for resistance, such as PI 398998, PI 437323, and PI 549017, had the lowest AUDPC units in at least one of the experiments. These genetic resources may be useful for host plant resistance studies and breeding soybeans for rust resistance in Vietnam and other locations like Brazil and the United States that have more recently been inundated with soybean rust. A significant (P < 0.001) experiment × genotype interaction was found when the AUDPC data of 14 soybean genotypes tested in Experiments 1, 2, and 3 were combined and analyzed. This result indicates the potential importance of changing fungal races and/or biotypes that occur in the rust population.     

Marker-assisted pyramiding of four QTL/genes for Asian rust (Phakopsora pachyrhizi) resistance in soybean

Gene pyramiding (assembling multiple desirable genes into a single genotype) via conventional methods to combat Asian rust resistance in soybean (Glycine max (L.) Merrill) and developing soybean varieties with durable resistance to this disease continues to be a challenge. Therefore, our objectives were to pyramid four Asian rust (caused by Phakopsora pachyrhizi) resistance (Rpp) genes, viz., Rpp1, Rpp2, Rpp3, and Rpp4 from their respective donors, PI200492 (Komata), PI230971, PI462312 (Ankur), and PI459025 (Bing Nan). Two single crosses (PI200492 × PI230971; PI462312 × PI459025) and a double-cross [(PI200492 × PI230971) × (PI462312 × PI459025)] were made for present study. The scoring of parents and crosses was done according to a 0–9 grading scale, where 0 = 0% disease intensity (absolutely resistant), 1 = 1% disease intensity (highly resistant), 3 = 1.1–10% disease intensity (moderately resistant), 5 = 10.1–25% disease intensity (moderately susceptible), 7 = 25.1–50% disease intensity (susceptible), and 9 = more than 50% disease intensity (highly susceptible). Out of four parents used, Rpp1 gene-donor plant introduction (PI)200492 (Komata) was immune to rust, with a disease grade of 0.92. Rpp2 and Rpp4 gene donors, PI230971 and [PI459025 (Bing Nan)], had reddish-brown (RB) lesions. Rpp3 gene-donor PI462312 (Ankur) showed a few, highly localized patches of tan lesions; however, it was not as susceptible as the susceptible check JS335. In cross-A (PI200492 × PI230971), all the F₁s were rust resistant, whereas in the F₂, 93.9% (845 plants) were either immune (11.0%, 99 plants) showing no infection or had RB lesions (82.9%, 746 plants) with resistant reaction and the remainder 6.1% (55 plants) had susceptible reaction. In cross-B (PI462312 × PI459025), 80.8% (63 plants) of the F₁ had RB lesions and resistant reaction, whereas 19.2% (15 plants) had susceptible reaction. In its F₂ population, 24.2% (217 plants) were susceptible. In cross-C [(PI200492 × PI230971) × (PI462312 × PI459025)], i.e., double-cross hybrid (DCH), 85.5% (77 plants) were either immune or had RB lesions, whereas the rest of the plants 14.5% (13 plants) showed susceptible reaction. Based on parental survey, four simple sequence repeat primers were short-listed for amplification of individual rust-resistance gene-specific markers in ten plants of each cross, viz., Satt191-210bp (Rpp1 gene), Sat_361-245bp (Rpp2 gene), Satt263-195bp (Rpp3 gene), and Rpp4TM-128bp (Rpp4 gene). In the single-cross hybrid (SCH)-A (PI200492 × PI230971), six plants had both Rpp1 and Rpp2 genes, whereas in another SCH-B (PI462312 × PI459025), seven plants had both Rpp3 and Rpp4 genes. In DCH [(PI200492 × PI230971) × (PI462312 × PI459025)], a single plant had all four Rpp genes, five plants had two Rpp genes, whereas a single susceptible plant had only Rpp3 gene. The homozygous rust-resistant segregants from these crosses can be used for improving rust resistance of otherwise adapted, high-yielding soybean genotypes.     

大豆锈病研究进展

1899年在中国的吉林首次报道了由豆薯层锈菌(Phakopsora pachyrhizi Syd)引起的大豆锈病。20世纪60年代大豆锈病成为热带、亚热带地区大豆生产中最严重的病害，进入本世纪后，大豆锈病成为世界性病害。对大豆锈病较为系统的研究始于20世纪70年代，目前对大豆锈病的病原菌分类、分布及其寄主、病原夏孢子生物学特性、病害流行、抗锈资源鉴定、抗锈遗传都有较为详细的研究，但对冬孢子的作用、生理小种的分化和鉴定、锈菌的交替寄主、锈病的初侵染源都还缺乏深入的研究，至今尚未发现对锈菌免疫的抗源，限制了锈病的防治和抗锈遗传育种的开展。     

大豆抗锈种质的评价

对14个国内外大豆抗锈种质在福建地区的抗锈性及农艺性状进行了评价。结果表明:抗锈基因Rpp1、 Rpp2、Rpp3和Rpp4 (屏南豆)的抗性已被克服,抗锈种质樟子乌、九月黄和日向可能含有新的抗锈基因。来自国外 的抗锈种质在福建地区未能表现出对锈病的抗性,农艺性状较差,不适宜直接利用。     

大豆锈病越冬区气候区划研究

根据1951-2001年间全国743个气象站点的气象数据,结合大豆锈病越冬所需气候条件,采用地理信息系统分析获得了大豆锈病在我国越冬区区划图,以供我国各个地区统一协调管理大豆锈病时参考使用.根据生物气候相似距原理,以琼海为中心,以计算的前一年12月初到下一年2月底的时间段内各个旬均温、月最高温、月最低温、旬降雨量为气候要素,计算琼海与其余742个气象站点的气候相似距,用地理信息系统软件Arcmap对相似距值按Kriging法进行插值,生成的地图表明,大豆锈病可在海南岛、广东南部较大范围内越冬,而云南和广西只有局部地区适合大豆锈病越冬.该区划结果需要进一步实地调查验证.     

中国大豆种质资源抗大豆锈病鉴定

１９９６～１９９９年对我国１０１８份大豆种质资源进行抗大豆锈病鉴定,其结果未见免疫和高抗资源,仅有嘟噜豆－２等９份中抗资源,占鉴定总数的０．８８％,感病资源１００９份,占鉴定总数的９９．１２％。     

Responses of soybean genotypes to pathogen infection after the application of elicitors

Soybean diseases and pests can affect soybean production. One emerging pest management method is to treat plants with chemical elicitors at nontoxic levels to induce host resistance. The objective of this research was to determine if elicitors, benzothiadiazole (BTH), chitosan (CHT), phenylalanine (PHE), and salicylic acid (SA), applied to soybean foliage could alter the response of soybean genotypes to soybean pathogens. Two of the soybean genotypes had been previously shown to produce high or low amounts of reactive oxygen species (ROS) in response to elicitation. In the greenhouse, soybean genotypes were challenged with three pathogens 48 h after elicitation. Plants of the cultivar Pharaoh (susceptible control) treated with SA, and then inoculated with Macrophomina phaseolina had a shorter (α = 0.05) stem lesion length (34 mm) than the water control (55 mm). Plants of soybean genotype LD00-2817p (high capacity to produce ROS) and the cultivar Sloan treated with BTH, PHE, or SA, and then inoculated with Phytophthora sojae had greater (α = 0.05) survival rates than plants treated with the water control. The four elicitors and a water control were evaluated on LD00-2817p and LDX01-1-65 in the field for two consecutive years. Foliar disease incidence and severity were low for both years, although there were some differences in stem disease ratings. For example, charcoal rot stem severity rating was reduced (α = 0.05) from 2.0 in the water control to 1.1 with a PHE treatment for LD00-2817p and was reduced (α = 0.05) from 3.8 in the water control to 2.6 with SA for LDX01-1-65 in 2013. Both greenhouse controlled experiments and field experiments showed that genotype-specific elicitation reduced disease severity in some cases, but the differences were greater under controlled-inoculated conditions.