Use of Sinorhizobium (Ensifer) fredii for soybean inoculants in South Spain

The symbiotic potential of fast-growing soybean rhizobia isolated from diverse provinces of China, including S. fredii SMH12 from Vietnam, has been evaluated. All of them produced nitrogen-fixing nodules with the American soybean cultivar Osumi under greenhouse and field conditions. Two years of field experiments conducted in two localities in South Spain with alkaline and moderately acid pH soils showed that seed yields of soybean plants inoculated with fast-growing strains SMH12, WH1, WH8 and WW4 were similar or higher than those obtained with soybean inoculated with the reference slow-growing Bradyrhizobium japonicum strain USDA110. Competitiveness studies between S. fredii SMH12 and B. japonicum USDA110 demonstrated that soybean cultivar and pH of soil determined the outcome of the competition. Alkaline pH (7.8) favoured SMH12 to occupied nodules with American soybean cultivars while USDA110 was more competitive in soils with a moderately acid pH (6.6). The Asiatic cultivar Peking was almost exclusively nodulated by SMH12 in both types of soils. On the other hand, the percentage of nodules occupied by fast-growing soybean inoculants applied into a soil containing indigenous Bradyrhizobium population of 4 × 10³ rhizobia/g was inferior to 18%. SMH12 occupied a 7% and 17% of the nodules with Osumi and Kochi soybean cultivars, respectively.     

Soybean Genotypic Variation for Nitrogen Fixation

Eighteen soybean ( Glycine max [L.] Merr) cultivars from maturity groups V and VI were screened with two Bradyrhizobium japonicum strains (USDA 110 and TAL 378) in the greenhouse to determine N₂ fixation (C₂H_2: reduction) rates. Antibiotic resistant markers were used for observing nodule occupancy. Cultivars L.-76-0132, PI 159319, Hoberland, Lee, PI 22173 and Centennial showed high nitrogenase activity of 6.25, 5.54, 17.43, 4.73, 6.94, and 4.81 μM C₂H₄/Pl/hr, respectively. Cultivars PI417419, PI 230978, Ogden , and FC 31665 showed low nitrogenase activity of 1.51, 0.80, 0.62 and 0.94 μM C₂H₄/Pl/hr, respectively. The data from this screening experiment suggest that the N₂ fixation varied among genotypes and all the nodules were occupied by the inoculated strains only. Rhizobial strain effect was observed among soybean cultivars (MGVI).     

应县小黑豆与大豆胞囊线虫3号生理小种互作关系研究

摘要：对抗病品种应县小黑豆与大豆胞囊线虫3号生理小种（SCN3）互作及田间动态关系进行了研究。结果表明：应县小黑豆为抗扩展品种,对SCN3明显抑制J2向J3,J3向J4的发育,并且对SCN3的雌雄分化有一定影响。在抗病植株上观察到的J4大部分是雄虫,雌虫极少,而感病品种辽豆15上,SCN3各龄期之间发育正常,根内J4大部分为雌虫。应用冰冻切片技术对线虫侵染后抗感品种根系组织进行切片观察。观察结果表明：抗感品种的组织病理学反应有明显差异,抗病品种产生明显的组织病理学反应,表现为根内线虫虫体附近根组织细胞有坏死现象发生,而感病品种辽豆15则无坏死现象。并且观察到抗病品种根内产生的合胞体。     

Soybean-Rhizobium Combination for Tolerance to Low P-High Aluminum

Two greenhouse experiments were conducted to evaluate the performance of selected soybean- Bradyrhizobium combinations in a soil having low P-high aluminum stresses under controlled conditions. Growth parameters such as plant height, nodule numbers, dry weight, nitrogenase activity and seed yield were used as an index. Three selected acid (low P-high Al) tolerant ( Essex, Tracy and Bedford ) and three sensitive ( Peking, Hill and McNair 600 ) soybean ( Glycine max ) varieties were sown in each pot. Three of the most tolerant strains of Bradyrhizobium (USDA 6, 110, 122), a mixture of these strains, and a commercial inoculant (Nitragin) were used to inoculate the Hartselle sandy loam soil. The results indicated that soil acidity significantly affected the soybean Bradyrhizobium symbiosis. The combination of variety Tracy plus Nitragin (mixed-strain) produced the highest and variety Peking plus mix-strain Nitragin the lowest plant height at all pH levels. Plants inoculated with Nitragin had higher shoot dry weight and seed yields. Variety Essex in combination with Nitragin produced the highest seed yields at all pH levels. Plants inoculated with Nitragin developed significantly more nodules than the other strains except for variety Peking. There was no significant difference in total nodule numbers between tolerant and sensitive soybean varieties at all soil pH levels except for Nitragin. Shoot total N did not increase by increasing the pH level or by using different variety-strain combinations.     

山东省2个大豆孢囊线虫群体生理小种鉴定及其烟草寄生性测定

为探究大豆孢囊线虫(SCN)即墨群体和莒县群体的生理小种类型及其对烟草的寄生性,采用杯栽试验和孢囊定量接种方法,测定2个SCN群体在5个大豆品种(4个生理小种鉴别寄主和1个感病对照品种Lee)和6个烟草品种上的繁殖和侵染情况。结果发现,SCN即墨群体在5个大豆品种上的繁殖系数(Rf=Pf/Pi)为1.88(0.05~9.03),在感病对照品种Lee上Rf高达9.03;在6个烟草品种上的Rf为0.01(0.00~0.04)。SCN莒县群体在5个大豆品种上的Rf为1.23(0.05~5.28),在感病对照品种Lee上Rf高达5.28;在6个烟草品种上的Rf为0.16(0.00~0.65)。研究表明,SCN即墨和莒县群体分别属于3号和6号生理小种,系这2个小种在山东省的首次发现。SCN即墨群体对6个烟草品种几乎均无寄生性,而莒县群体则对部分烟草品种(云烟85和NC95)有一定寄生性。     

Effect of Nematicide and Herbicide Interactions on Field Population of Cyst Nematode and Agronomic Characters of Soybean

Treatment of herbicides (Treflan and Lorox) and nematicides (Nemacur and Temik) and various combinations of these pesticides on Essex and Ransom in the field to control weeds and soybean cyst nematode (SCN) have produced significantly more abnormal seedling establishment, more number of pods and nodules per plant, and lesser field population of SCN. The differences in performance of Essex and Ransom with respect to SCN control with corresponding yield increases or decreases from pesticide treatments may have been due to the cultivar's different degree of susceptibility to SCN infestations and to their specific genetic make-up. The recommended nematicides for the control of SCN with corresponding yield increases in Essex were Temik and Nemacur and the recommended nematicide-herbicide combinations were Temik-Treflan and Temik-Lorox. The recommended nematicide for the control of SCN in cultivar Ransom was Temik. Bean yields were not affected by the application of pesticides.     

The Effect of Different Planting Dates on the Infestation of Soybean by Heterodera glycines Race 5

The effects of different planting dates on infestation of susceptible soybean cvs. Essex and Lee by Heterodera glycines were investigated during three growing seasons. Early planting dates of susceptible soybean cvs. at lower temperatures resulted in smaller nodules, lower nematode populations and field infestations, lower soybean cyst nematode (SCN) disease ratings, taller plants, and higher yields. SCN induced more nodules on soybean roots at 14 May plantings date. The development of SCN race 5 in the field was associated closely with soil temperature. The infestation of susceptible soybean cvs. at early planting dates by H. glycines greatly affected the agronomic performance of these cvs. in the field. Susceptible soybean cvs grown in infested soil with SCN race 5 planted earlier than the recommended planting dates escaped severe infestation of SCN in the field.     

冀豆系列品种抗病基因型分子推断

大豆花叶病毒病(SMV)和大豆孢囊线虫病(SCN)是危害大豆生产的重要病害。本试验以冀豆系列14个品种为材料,利用RAPD和SCAR标记技术对其进行了大豆花叶病毒病和孢囊线虫病的抗病基因型分析,以寻找可供在大豆生产和育种中利用的抗源。所用引物为重复性较好的OPL_07,OPAO_19和SCW_05。通过分析,我们初步推断冀豆4号和五星一号同时具有大豆花叶病毒SC和Sa两种株系的抗性基因,其中五星一号既具有大豆花叶病毒病抗性基因同时还具有大豆孢囊线虫病抗性基因,可推荐作为大豆生产和育种中优先选用的抗源材料。     

Genotype x Bradyrhizobium japonicum strain interactions in dinitrogen fixation and agronomic traits of soybean (Glycine max L. Merr.)

Summary Bradyrhizobium japonicum strain G49 has been the only inoculum used in French soils. Soybean (Glycine max L. Merr.) cultivars were selected and tested according to their performances with this rhizobial strain. The aim of the present study was to determine the consequences of strain substitution on N₂ fixation abilities of various genotypes. Three genotypes and cultivar Weber, in combination with B. japonicum strain G49 or SMGS1, were cultivated in pots and tested for nitrogenase activity under differing nitrogen nutrition conditions. The reliability of ARA (acetylene reduction activity) measurement for assessing symbiotic nitrogen fixation under the experimental conditions used was checked. Genotypic variability for symbiotic fixation activity was observed with each strain under soil culture conditions; important genotype x strain interactions were also involved. These results were corroborated for the protein yield and other yield component performances of the various genotype-strain associations. Thus, in France, the replacement of strain G49 with another one might result in the alteration of the relative agronomic performances of the soybean cultivars, since N₂ fixation is considered as a major factor of soybean productivity.     

A single dominant gene in McCall soybean prevents effective nodulation with Rhizobium fredii USDA257

Summary Rhizobium fredii USDA257 will effectively nodulate Asiatic and unimproved soybean cultivars, such as Peking, but most of the highly selected North American cultivars, such as McCall, produce at most rudimentary, ineffective nodules. In R. fredii USDA 257, a locus containing 6 open reading frames is responsible for this cultivar specific incompatibility. To examine the genetic control of incompatability on the part of the host, the soybean cultivars Peking and McCall were crossed to produce five F₁ progeny. These plants and their selfed progeny were tested for nodulation with USDA257. Resistance to nodulation was found to be conditioned by a single dominant gene. These results indicate that, in soybean, strain specific resistance to nodulation can result from gene(s)-for-gene interactions.     

水氮耦合对直播早籼稻苗期低温冷害的调控效应

为探究水氮耦合对直播早籼稻苗期低温冷害的调控作用,以耐冷品种湘早籼6号和冷敏感品种中嘉早17为供试材料,设置适温不施氮（CK）、低温不施氮（LT-0N）、低温低氮（LT-LN）、低温高氮（LT-HN）、低温淹水不施氮（LTF-0N）、低温淹水低氮（LTF-LN）和低温淹水高氮（LTF-HN）7个处理,处理5d,分析秧苗农艺性状、抗氧化酶活性、渗透调节物质、氮代谢相关酶与光合酶活性、内源激素含量等生理生态特性。结果表明,水氮耦合可缓解低温冷害对直播早籼稻造成的伤害。与LT-LN处理相比,LT-HN处理5d后冷敏感品种中嘉早17的苗高、根数、最大根长、鲜重、干重、顶部第1和第3片叶长显著增加;与LTF-0N处理相比,LTF-LN和LTF-HN处理5d后,不同耐性品种的根数、根长、鲜重和顶部第3片叶长显著增加,LTF-LN处理的根数和鲜重高于LTF-HN处理。与LT-0N处理相比,LT-HN和LTF-LN处理显著增加冷敏感品种中嘉早17叶片氮代谢相关酶和光合酶活性、硝态氮、叶绿素和内源生长促进类激素含量,但降低了叶片抗氧化酶活性、可溶性蛋白、渗透调节物质和内源生长抑制类激素含量,高氮和淹水低...     

黑龙江大豆栽培品种和新品系对疫霉病抗性评价及抗病基因分析

由Phytophthora sojae引致的大豆疫霉病是黑龙江大豆产区的重要病害之一。该病已在我国大豆一些主要栽培区发生,并引起较大危害。培育和种植抗疫霉病品种是控制该病最有效的方法。本研究旨在筛选黑龙江地区的大豆疫霉病抗病品种和品系,为病害的防治和抗病品种的合理布局提供参考。在大豆苗期用下胚轴伤口接种方法对126个栽培大豆品种和135份大豆品系进行接种,鉴定其对黑龙江大豆主要疫霉病菌株（8个）的抗性。鉴定结果表明：有72个品种抗4个以上菌株,占鉴定品种的57.1%;84份品系抗4个以上菌株,占鉴定品系的62.2%。对品种的基因分析表明,有30个大豆品种含有抗病基因,其中有10个品种分别含有Rps1k、 Rps3a、Rps1c三个主要基因。     

Agronomic traits of soybean cultivars released in different decades after grafting record‐yield cultivar as rootstock

Breeders have seldom considered the selection for root traits during the genetic improvement in soybean. It is hypothesized that grain yield would be increased by the root function improvement, especially for the current cultivars. The objective of this grafting experiment was to determine the effect of record‐yield cultivars L14 or Z35 as rootstocks on agronomic traits of cultivars released in different decades. A total of 11 cultivars, released in different decades, were used to graft onto L14 or Z35 rootstocks. The agronomic traits were measured in the pot‐culture experiments. Grafting cultivars released in different decades onto L14 or Z35 rootstocks resulted in higher yield, 100‐seed mass and apparent harvest index as compared with those of non‐grafted or self‐grafted plants. Grain yield gain of cultivars grafted onto record‐yield cultivar rootstocks was 0.40 g/plant/year from 1966 to 2006, which was larger than that of non‐grafts and self‐grafts (0.27 g/plant/year). The yield of current cultivars should increase more if their root functions were improved.     

大豆抗源抗SCN过程中POD酶动态分析

能动地大豆抗源抗孢囊线虫（ＳＣＮ）过程中过的氧化物酶（ＰＯＤ）活性和酶谱的变化研究,探讨了大豆抗源在抗病过程中是通过提高体内ＰＯＤ酶活性来抵御ＳＣＮ的侵染,抗源品种ＰＯＤ活性和酶谱呈动态变化。在侵染高峰期（３０￣３５ｄ）,高抗抗原体内ＰＯＤ酶活性最强,酶谱着色较深;而感病品种在侵染高峰期ＰＯＤ酶活性降至最低值,且一些酶带受损以至消失。另外,证实了ＰＯＤ酶在抗病过程中参与木质素的合成。抗病过程中酶活     

Cultivar × rhizobial strain interactions in peas with respect to early symbiosis, nodule initiation and N uptake

Sixteen pea cultivars differing in their phenotypic characteristics were studied in order to characterize the cultivars' variability in symbiotic characters using three Rhizobium leguminosarum biovar viceae strains. The peas did not show any cultivar × strain interactions with the rhizobial strains used with respect to root hair infection frequency or day of nodule initiation. Three cultivars had high root hair infection frequencies, and five had only a few infected root hairs. Four of five leafless/semi-leafless varieties investigated and one cultivar with normal leaves formed nodules quickly, whereas three varieties with normal leaves formed nodules slowly. Ten of the cultivars showed cultivar × strain interactions with respect to N uptake, indicating that the performance of the N2-fixing symbioses depends on the rhizobial partner. Six cultivars showed cultivar × strain interactions with respect to dry matter production and the nodule proportion of the dry matter. Of the cultivars investigated, we conclude that some of the leafless/semi-leafless varieties (‘Capella’, ‘Filby’ and ‘Solara’) are suitable for inclusion in a future breeding programme, since these cultivars combined several important symbiotic characters.     

重组型大豆花叶病毒河北分离物序列特征及侵染性

重组型大豆花叶病毒(recombined soybean mosaic virus,SMV-R)是一种新SMV类型,在我国多个大豆产区广泛流行。本研究对一个重组型SMV河北分离物(HB-RS)进行全基因组测序,比较与非重组型SMV在侵染4个大豆品种后病毒浓度积累的差异。结果显示,除poly-A尾巴外,HB-RS(NCBI登录号为KR065437)由9993个核苷酸组成,包含一个开放阅读框(open reading frame,ORF),翻译后形成3202个氨基酸,系统进化分析结果显示HB-RS分离物与另外两个重组型SMV分离物聚在一组。抗性鉴定结果显示,4个品种对HB-RS和Sc6平均病情指数分别为59.5和60.5,相同大豆品种对不同的株系(分离物)可能呈现不同的症状和抗性表现,其中冀豆17对Sc6和HB-RS分别表现高抗和中抗,表明大豆对SMV的抗性存在一定的株系(分离物)专化性。此外,HB-RS在4个品种中的浓度积累均高于Sc6,在南农1138-2病毒浓度最高,达522 U,其次为五星1号(471 U)和冀黄13(199 U),最低为冀豆17,仅90 U。说明HB-RS在寄主体内更具有生存适应性,不同品种对SMV存在抗性差异。冀豆17可作为抗性品种和亲本进一步推广。     

黄淮海地区大豆主栽品种对8个大豆疫霉菌株的抗性评价

随着麦茬免耕栽培技术的推广应用,黄淮海地区麦后夏播大豆生产中疫霉根腐病呈加重趋势。了解该地区大豆主栽品种对疫霉根腐病的抗性和筛选抗病亲本,对培育新的高产广适抗病品种具有重要意义。本研究利用8个具有不同毒力的大豆疫霉菌株,采用下胚轴创伤接种法,对20世纪50年代以来黄淮海地区审定、推广的140个大豆主栽品种进行接种鉴定。表明除6个品种对8个菌株均无抗性外,其余134个品种分别抗1~8个大豆疫霉菌株,占鉴定品种总数的95.7%,其中抗6~8个以上菌株的品种有83个,占鉴定品种总数的59.3%。以14个鉴别寄主的抗病反应型为参照,发现134个品种对8个大豆疫霉菌株共产生65种反应型,其中19个品种产生的5种反应型与已知单基因或2个单基因组合反应型相同;115个品种产生的60种反应型与含有已知单基因或2个单基因组合的反应型不同,推测可能含有新的抗病基因或基因组合。根据研究结果合理选择亲本,可培育出聚合多个抗性基因且综合性状优良的大豆新品种。     

氮素对不同来源大豆品种农艺性状及产量的影响

在田间条件下,以12个不同来源大豆品种为试验材料,采用二因素裂区设计,研究氮素对不同来源大豆品种农艺性状及产量的影响.结果表明:追施氮肥会使大豆品种的株高、分枝数和单株荚数增加.当尿素施用量为100 kg/hm2时,和不施肥相比,3组不同来源大豆品种的主茎节数增加,俄亥俄当代品种与辽宁当代品种结荚高度则会降低.氮肥处理能提高俄亥俄当代品种与辽宁当代品种的粒茎比.当尿素施用量为200 kg/hm2时,和不施肥相比,俄亥俄当代品种与辽宁老品种产量分别增加10.61%和1.63%;当尿素施用量为100 kg/hm2时,和不施肥相比,辽宁当代品种产量会增加10.47%.     

Ureide essay to assess N<Subscript>2</Subscript>-fixation abilities of soybean (<Emphasis Type="Italic">Glycine max</Emphasis>) genotypes under different <Emphasis Type="Italic">Bradyrhizobium</Emphasis> strains

The high protein content of soybean (Glycine max) seeds results in high nitrogen demand, causing a huge nitrogen uptake during plant growth. As a legume crop, soybean can fix atmospheric N through symbiotic associations with Bradyrhizobia and perform well in African nitrogen poor soils. This study aimed at establishing the ability of promiscuous soybean genotypes to fix nitrogen and devise the relationship between nodule scores and amount of nitrogen fixed. Twelve soybean genotypes were inoculated with Bradyrhizobium japonicum Strain USDA 110 (specific) and Bradyrhizobium sp. Strain USDA 3456 (native) and raised in pots in a greenhouse. At the R3.5 growth stage, nodules were scored and xylem sap was extracted, which xylem sap was used to carry out ureide, amino-N, and nitrates assays. The relative abundance of ureide was used to devise the proportion of nitrogen fixed by each genotype. The proportion of nitrogen derived from atmospheric N2 (Ndfa) ranged from 47.9 to 78.8% under USDA 3456 and from 36.7 to 78.7% under USDA 110. A strong correlation was found between nodule scores, especially nodules’ effectiveness, and Ndfa. The genotypes Wondersoya (78.8%), Maksoy 2N (78.4%), Namsoy 3 (78.3%), and Maksoy 3N (75.7%) had high nitrogen-fixing ability in response to USDA 3456. Promiscuous soybean genotypes can fix nitrogen equally under both native and specific Bradyrhizobium types. Nodules’ effectiveness can be a good predictor of biological nitrogen fixation. This study highlighted that crop improvement to boost soybean production in Africa should target promiscuous varieties for better yield with less inputs.     

Genotypic Variation for Nitrogen Fixation in Soybean

Twenty soybean cultivars from maturity groups IV, V, VI, VII and VIII were screened in the growth chamber study to determine their response to two Rhizobium strains through N-fixation rates. Cultivars Lee 74, Essex and Bay showed high nitrogenase activities of 201.00, 93.75 and 74.86 nM C₂H₂/pl/hr, respectively. Braxton, Hutton and Bragg showed low nitrogenase activity rates of 4.73, 4.20 and 3.0 nM C₂H₂/pl/hr, respectively. A range of variation was found among the cultivars in shoot fresh and dry weights, nodule number and nodule weight.