赤斑黑沫蝉在玉米和水稻上为害加重的原因

赤斑黑沫蝉属同翅目沫蝉科。为害水稻、玉米、大豆、红薯等多种作物 ,被害作物叶片逐渐枯黄 ,严重为害可造成作物整株枯黄死亡 ,减产十分严重。２０世纪９０年代初赤斑黑沫蝉在思南县玉米、水稻等作物上仅零星发生为害。近年来由于暖冬气候和农户对赤斑黑沫蝉防治方法不当 ,使赤斑黑沫蝉在玉米、水稻上发生呈上升趋势。１９９５年全县稻田发生面积１６００ｈｍ２,占全县稻田面积８．９% ;１９９８年稻田发生面积８０００ｈｍ２,占全县稻田面积４６．１５% ,１９９９年稻田发生面积１１３３３ｈｍ２,玉米发生面积１４６７ｈｍ２,占全县稻田、…     

玉米秸秆深层还田技术对土壤肥力和玉米产量的影响研究

采用田间试验,利用玉米秸秆深层还田技术对0～40 cm土层土壤肥力和玉米产量的影响进行了研究。结果表明,玉米秸秆深层还田不仅能改善土壤理化性质,培肥土壤,还能增加玉米产量。秸秆深层还田3年后0～20 cm土层有机质含量提高了1.8%～8.38%,速效氮含量提高了5.47%～14.66%,速效磷含量提高1.33%～1.42%,速效钾含量提高了1.77%～5.31%,容重降低了0.75%～4.51%;20～40 cm土层有机质含量提高了11.94%～46.27%,速效氮含量提高了6.15%～30.82%,速效磷含量提高1.74%～2.98%,速效钾含量提高了4.3%～13.98%,容重降低了5.52%～13.79%;深层秸秆还田后玉米增产量有明显的增加趋势,增产量在4.7%～8.5%之间。     

秸秆还田对水稻根际微生物多样性和水稻纹枯病发生的影响

为探究稻麦轮作模式下秸秆还田对水稻根际微生物多样性与水稻纹枯病发生的影响,本研究采用Illumina测序技术结合生物信息学比较分析了秸秆还田与不还田处理的水稻根际微生物群落多样性差异,并采用实时荧光定量PCR （real-time fluorescent quantitative PCR,RT-qPCR）对这2种稻田土壤中水稻纹枯病菌Rhizoctonia solani含量进行测定,并采用随机五点取样法调查稻田中水稻纹枯病发病率和病情指数。结果表明,秸秆还田后水稻根际细菌群落Chao1丰富度指数和Shannon多样性指数均有所增加,分别增加14.42%和4.39%,其中前者增幅显著;根际真菌群落Chao1丰富度指数降低29.60%,而Shannon多样性指数略有增加,增加5.96%;在门水平上,秸秆还田和不还田处理的水稻根际土壤优势细菌门均为变形菌门、放线菌门、绿弯菌门和酸杆菌门,优势真菌门均为子囊菌门、接合菌门和担子菌门;在属水平上,秸秆还田处理的硝化螺旋菌属和芽胞杆菌属相对丰度分别比不还田处理的显著增加96.11%和106.19%;在水稻孕穗期秸秆还田土壤中水稻纹枯病菌含量比不还田处理的显著增加120.20%;秸秆还田后水稻纹枯病发生加重,病情指数比不还田处理的增加18.10%~45.41%。     

水稻基腐病细菌和玉米茎腐病细菌的比较研究

 对水稻基腐病细菌(18个菌株)、玉米茎腐病细菌和菊欧氏杆菌的6个致病变种的标准菌株及胡萝卜软腐欧氏杆菌的两个致病变种(Erwinia carotovora pv.carotovora和E.c.pv.atroseptica)进行了58项生化试验的比较。结果水稻菌株在生化性状上与玉米菌株十分相似,最接近菊欧氏杆菌玉米致病变种(E.chrysanthemi pv.zeae),但水稻基腐病细菌在兰色素产生,丙二酸、酒石酸钠利用,产氨和过氧化氢酶活性等项上与玉米致病变种不同。在致病性比较中,水稻菌株比玉米菌株致病力强,寄主范围广。可能是一个独特的致病变种。全细胞蛋白聚丙烯酰胺圆盘电泳的研究表明水稻菌株的蛋白电泳带数与玉米菌株相同,均为16条,但电泳带的迁移率互不相同。血清学研究表明水稻基腐病细菌和玉米致病变种没有共同抗原。     

水稻秸秆还田结合炔草酯对禾本科杂草和小麦生长发育的影响

为改进水稻秸秆还田条件下小麦田杂草治理技术,通过田间小区试验研究了不同还田量单独或结合炔草酯施用对后茬小麦田禾本科杂草的控制效果和小麦生长发育及产量的影响。结果表明,随着水稻秸秆单独还田量从1 125 kg/hm2增至4 500 kg/hm2,小麦田杂草发生密度显著下降,4 500 kg/hm2秸秆还田量下小麦分蘖期前杂草发生密度下降60%左右;结合炔草酯施用时,杂草发生密度随秸秆还田量的增加而下降,但不同还田量之间无显著差异,且炔草酯除草活性未受到影响。秸秆还田或炔草酯单独或结合施用均对小麦生长发育无明显的胁迫影响,4500 kg/hm2秸秆单独还田量下,小麦苗期功能叶SPAD值较对照增加7.0%,净光合速率和蒸腾速率分别增加14.9%和12.2%;抽穗期净光合速率、气孔导度、蒸腾速率分别增加28.3%、85.2%和100.0%;千粒重、有效穗数和产量分别增加3.9%、6.7%和16.1%。4 500 kg/hm2秸秆单独还田量对杂草控制效果、小麦生长及产量的影响均与炔草酯推荐剂量单独施用无显著差异,表明该秸秆还田量具有良好的农田生态效应。     

海河平原秸秆覆盖和春季灌水对小麦玉米产量和水分利用的影响

针对海河平原水资源短缺和小麦-玉米水分利用现状,通过2013—2015年大田试验,设置春季不灌水、春季不灌水+秸秆覆盖、春季1水、春季1水+秸秆覆盖四个处理,研究了春季灌水和秸秆覆盖对小麦-玉米两熟作物生长、产量和水分利用的影响。结果表明:灌水和秸秆覆盖效应主要体现在小麦拔节到开花期。小麦拔节~开花期,由于灌溉和秸秆覆盖保温保墒作用,两个生长季中,春季1水秸秆覆盖LAI高于1水不覆盖处理,但开花期后这种效应逐渐消失,花后10天和20天覆盖LAI低于不覆盖处理,且差异显著;春季不灌水由于水分胁迫,无论秸秆覆盖与否,LAI差异不显著。2013—2014年,和不覆盖相比,春季0水覆盖产量降低了1.46%,春季1水处理覆盖后降低了2.76%;2015年春季0水覆盖降低了2.78%,春季1水覆盖降低了1.11%。但春季灌溉1水后,与不灌水相比,2014年产量差异显著,2015年差异不显著。随着灌溉水量的增加,土壤耗水量减少,两年中小麦生长季土壤耗水量都表现为春季0水大于春季1水,且差异显著;相同水分条件下不覆盖大于覆盖处理,但差异不显著。不同处理小麦生长季土壤耗水量的差异及玉米生长期间的降水量共同影响了玉米土壤耗水量,覆盖处理的耗水量小于不覆盖处理。从水分利用效率看,小麦、玉米和周年土壤水分利用效率各处理间和年份间都没有显著差异。海河平原水分有限条件下,秸秆覆盖后在小麦需水敏感期限量灌水在保证产量基础上可降低耗水量,因此春季灌溉1水结合秸秆覆盖是实现本区域小麦-玉米种植制度节水的有效措施。     

秸秆和紫云英覆盖还田对玉米光合生理特性的影响

为探究秸秆和紫云英覆盖还田对玉米光合生理特性的影响,设置半量秸秆覆盖(HS)、全量秸秆覆盖(WS)、紫云英覆盖(M)、半量秸秆加紫云英覆盖(HS+M)、全量秸秆加紫云英覆盖(WS+M)、无覆盖(CK)6个处理,于玉米乳熟期测定光合气体交换参数的日变化、光响应曲线以及叶片生理指标和干物质量等。结果表明,净光合速率和气孔导度都呈“双峰”曲线变化,胞间二氧化碳浓度（C_i）和蒸腾速率(T_r)整体呈“单峰”曲线变化;HS+M处理的日平均净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)最高且较CK处理分别显著增加了33.44%、60.81%、33.36%,而各处理间的日平均胞间C_i差异不大;光响应曲线中,WS+M处理的P_nmax和LSP的实测值在各处理中最高,分别为23.46、1 900 mol·m^-2·s^-1,且各处理的光响应曲线拟合决定系数均高于0.99;Rubisco和PEPC的活性在各处理间均表现为：WS+M>HS+M>M>WS>HS>CK,各处理中,以WS+M处理的Rubisco和PEPC活性最高分别为12.92 U·L^-1、6.59 U·L^-1,且较CK处理高出1.12和1.59倍;玉米穗位叶叶面积和地上部分单株干物质量都以WS+M处理最高,分别较CK处理显著增加了16.40%、46.32%;气体交换参数与玉米叶片生理指标间均呈正相关关系。本研究结果表明,将秸秆、绿肥覆盖还田可提高玉米的光合作用能力,促进玉米地上部分干物质积累,为玉米最终增产提供物质基础。     

秸秆还田配施氮肥对夏玉米灌浆过程和产量的影响

针对京都“冬小麦一夏玉米”种植制度下秸秆还田十分普遍,然而氮肥施用却常常过量这一现状,探讨了秸秆还田配施氮肥对夏玉米灌浆过程和最终产量的影响。试验设秸秆还田和秸秆不还田2个因素,不施氮、传统施氮和优化施氮3个氮肥水平。结果表明：秸秆还田配施氮肥,夏玉米的籽粒体积增加了17．38％～19．69％,高速灌浆持续期较对照延长5～7d,夏玉米产量提高显著,尤其是秸秆还田 优化施氮处理产量最高,达到7385．1kg／hm。;秸秆还田优化施氮的穗粒数达到598．19粒／穗,与秸秆不还田不施氮处理相比增加了27．3％,秸秆还田传统施氮处理的千粒重最大,达到239．75g／1000粒。通过对比分析,认为“秸秆还田 优化施氮”是京郊地区适宜采用的一种增加作物产量的优化耕作模式。     

不同秸秆还田量对旱地土壤水肥和玉米生长与产量的影响

以阜新地区为例,开展不同秸秆还田量对旱地土壤水肥和玉米生长与产量的影响研究。试验设计0 kg·hm^-2,6 000 kg·hm^-2,12 000 kg·hm^-2,18 000 kg·hm^-2、24 000 kg·hm^-2共5个处理,3次重复,共15个小区,小区面积(4 m×15 m)为60 m²。研究结果表明,对照CK不施用秸秆处理,深耕加秸秆的方法,土壤含水量显著增加,除了对照之外,各个处理剂量之间的差异并不明显,且呈先上升而后下降趋势。说明秸秆在土壤中始终处于水分的非饱和状态,并不是秸秆剂量越大越好。各个层次土壤容重与对照相比变化较明显,其中10～20 cm深处土壤容重变化最大,各个处理土壤容重表现出随秸秆还田量增加土壤容重降低值减少的趋势,下降幅度为12 000 kg·hm^-2>6 000 kg·hm^-2>18 000 kg·hm^-2。秸秆还田处理,提高了植物的叶绿素含量,促进了植物的光合效率,以12 000 kg·h m^-2处理较好。不同处理对玉米产量影响差异显著,达到了5%的显著水平,施入量在0～12 000 kg·hm^-2之间,玉米产量呈上升趋势,超过18 000 kg·hm^-2产量呈下降趋势,因此建议推广剂量为12 000 kg·hm^-2。     

秸秆覆盖和根系互作对间作玉米生理特性及产量的影响

通过盆栽试验研究了不同秸秆覆盖水平和玉米/大豆间作系统中根系互作对玉米的影响。结果表明：秸秆覆盖 和根系互作可增加玉米成熟期单株绿叶面积和不同生育时期的叶绿素含量,且根系互作的作用随覆盖水平的提高而增强;玉米成熟期的植株含水量和根伤流显著受到覆盖的影响,而受根系互作的影响不显著(P＞0.05);覆盖和根系互作可提高玉米光合速率、气孔导度和蒸腾速率,而降低胞间CO₂浓度,其中相同隔根处理下,T1和T0间的差异显著;覆盖和根系互作可改善玉米产量各构成因素,并提高成熟期单株生物产量和经济产量。相关分析发现,玉米单株绿叶面积、叶绿素含量、根伤流速度、光合速率均与产量存在直线正相关关系。得出,覆盖和根系互作有利于改善玉米生理特性,提高产量,且根系互作的优势作用随覆盖水平的提高而增强。     

Characterization of Fusarium asiaticum and F. graminearum isolates from gramineous weeds in the proximity of rice fields in Korea

Fusarium graminearum species complexes (FGSCs), such as Fusarium asiaticum and F. graminearum, are important pathogens that cause Fusarium head blight (FHB) in several cereal crops worldwide. In this study, we collected 342 gramineous weed samples in the proximity of rice fields from May to June 2018 in Korea. Among the 500 Fusarium isolates from the weed samples, 13 species of Fusarium were identified, and F. asiaticum (41.2%), F. avenaceum (18.0%), F. acuminatum (16.4%) and F. graminearum (14.8%) were the most frequently isolated. The trichothecene genotype analysis showed that 206 F. asiaticum strains consisted of the nivalenol (NIV) genotype (n = 195, 94.7%) and 3-acetyldeoxynivalenol (3ADON) genotype (n = 11, 5.3%), whereas 74 F. graminearum strains consisted of the 15-acetyldeoxynivalenol (15ADON) genotype (n = 58, 78.4%) and 3ADON genotype (n = 16, 21.6%). Geographical differences were observed in the FGSC and trichothecene genotype compositions, which appeared host-dependent between the southern provinces and mid-eastern provinces. The aggressiveness assessment of FHB showed that the 3ADON chemotype was most aggressive followed by the 15ADON and NIV chemotypes in wheat, while the NIV chemotype was most aggressive followed by the 3ADON and 15ADON chemotypes in rice. The F. asiaticum strains grew slowly and produced fewer conidia and perithecia than the F. graminearum strains, regardless of their chemotypes. The results of this study suggest that F. asiaticum with the NIV chemotype has a host preference for rice, and FHB-causing pathogens can be harboured in gramineous weeds, which play a role in the dispersal of FHB pathogens to rice and other cereal crops.     

玉米禾谷镰孢茎腐病和穗腐病抗性鉴定接种方法的比较

田间采用不同人工接种鉴定方法对92份玉米种质同步进行玉米禾谷镰孢茎腐病和穗腐病抗性评价与筛选, 明确了东北春玉米产区玉米禾谷镰孢茎腐病?穗腐病抗性鉴定的最佳接种方法:茎节注射法在玉米禾谷镰孢茎腐病抗性精准鉴定中可更好地评价玉米种质的抗病性, 综合考虑接种方法的实用性和可操作性, 菌土覆盖法对大体量的规模化种质进行田间抗病性鉴定更具有优势; 双牙签法对玉米穗腐病抗性鉴定中在种质接种后发病的严重度?田间进行接种的可操作性和实用性等方面均优于花丝通道法?同时筛选出对玉米禾谷镰孢茎腐病抗性稳定的种质52份, 对穗腐病抗性稳定的种质66份, 对2种病害均表现稳定抗性的兼抗种质33份?     

MB和CMC液体培养基对禾谷镰孢产孢水平的影响

禾谷镰孢分生孢子定量接种是研究作物抗禾谷镰孢的必要手段?本试验利用绿豆(mung bean, MB)与羧甲基纤维素(carboxylmethyl cellulose, CMC)液体培养基在相同条件下培养禾谷镰孢, 比较两种培养基对禾谷镰孢产孢效率的影响; 并用两种培养基诱导分生孢子制成相同浓度孢子悬浮液, 对75个玉米家系进行人工接种鉴定, 检测不同培养基所产分生孢子致病性差异?结果表明, CMC培养基诱导分生孢子增长率(k2=1.125)大于MB培养基诱导增长率(k1=0.844)?在培养第14天, MB培养基诱导获得的分生孢子平均浓度为2.51×105个/mL, CMC培养基诱导的为3.62×105个/mL, 比MB培养基诱导多44.22%?用两种培养基诱生的孢子进行田间接种, 玉米穗腐病发病程度无明显差异?CMC培养基具有产孢快?孢子浓度高的优点, 是一种适宜禾谷镰孢分生孢子诱生的高效液体培养基?     

麦秸掩埋还田对赤霉菌(Fusarium graminearum Sehw.)存活率和水稻带菌的影响

In order to determine the influence of different straw concentrated buried depth to survival rate of Fusarium graminearum and carrier rate of rice, six treatments including four buried depths (5 cm, 20 cm, 35 cm, 50 cm) and ck (straw mulched and rotary tillage returned), were set up from July to November in 2011. The research turned out that the flooded time and returning depths significantly affected the survival days and survival rate of F. graminearum. In flooded condition, straw with F. graminearum were centralize-buried. The survival time of the F. graminearum was 18 days at the most. The straw with Gibberella return into soil could cause the soil contaminated. Straw mulching, rotary tillage returning and 5 cm buried will increased the cross-infection phenomenon of F. graminearum in wheat and rice, while buried over 20cm, the colonies were reduced and the rice won’t be infected with F. graminearum     

Effect of temperature on head blight of wheat caused by Fusarium culmorum and F. graminearum

The effect of small temperature differentials (16 vs. 20°C) on the pathogenicity of deoxynivalenol producing single isolates of Fusarium culmorum and F. graminearum and on the fusarium head blight (FHB) response of eight wheat cultivars was examined. Fusarium culmorum inoculation caused greater visual disease symptoms at 20°C than at 16°C, both overall and on an individual cultivar basis (overall AUDPC = 13·5 and 9·6, respectively) ( P  < 0·05). In contrast, F. graminearum inoculation caused greater overall visual disease symptoms at 16°C than at 20°C, both overall and at the individual cultivar level (overall AUDPC = 12·8 and 10·9, respectively) ( P  < 0·05). Results showed both F. culmorum and F. graminearum inoculations caused a greater loss in yield at 20°C (54·3 and 46·9% relative 1000-grain weight, respectively) compared with 16°C (73·3 and 66·9% relative 1000-grain weight, respectively) ( P  < 0·05). Fusarium culmorum -inoculated heads contained similar amounts of fungal DNA at both 16 and 20°C (1·9 and 1·7 ng mg⁻¹ of plant material, respectively) (not significant), while for F. graminearum inoculation, plants contained higher amounts of fungal DNA at 20°C (2·0 and 1·0 ng mg⁻¹ of plant material, respectively) ( P  < 0·05). Overall, there was a significant negative correlation between AUDPC and percentage relative 1000-grain weight at both 16 and 20°C ( r  =−0·693 and −0·794, respectively, P  < 0·01).     

春玉米区穗腐病病原菌组成、分布及禾谷镰孢复合种的鉴定

 本研究对2015年收集的春玉米区玉米穗腐病样本的病原菌进行了分离鉴定。结果表明,禾谷镰孢复合种(Fusarium graminearum species complex)的总分离频率最高,为35.90%,为优势菌。进一步分析显示,山西、河北、吉林和黑龙江省以禾谷镰孢复合种为主,分离频率分别为81.25%、 75.00%、 44.00%和44.44%;内蒙古以拟轮枝镰孢菌(F. verticillioides)为主,分离频率为56.25%;辽宁省拟轮枝镰孢菌和哈茨木霉(Trichoderma harzianum)的分离频率分别为34.48%和31.03%;而在陕西省,禾谷镰孢复合种、拟轮枝镰孢菌和亚粘团镰孢菌(F. subglutinans)分离频率均为28.57%。以禾谷镰孢复合种的EF-1α基因序列为基础构建系统发生树,进一步对分离到的禾谷镰孢复合种进行亚种鉴定。结果表明,春玉米区禾谷镰孢复合种为禾谷镰孢菌和布氏镰孢菌,且以布氏镰孢菌为主。     

禾谷镰孢FgCYP51B蛋白F511L突变对分生孢子产量及其对烯唑醇敏感性的影响

Phe511是禾谷镰孢甾醇-14α-脱甲基酶FgCYP51B活性口袋中的一个重要氨基酸。本研究中,我们探究了FgCYP51B蛋白中该位点突变后对禾谷镰孢主要生物学表型的影响,并通过分子对接探讨了可能的原因。结果表明禾谷镰孢FgCYP51B-F511L突变体在菌落形态、生长速率等表型上与野生型菌株PH-1没有明显差异。但是F511L突变导致分生孢子的产量严重降低,对烯唑醇的敏感性增强。分子对接发现突变后亮氨酸的长侧链使得烯唑醇的甲基发生扭转,侧链朝向发生改变,更有利于与蛋白受体形成较强的疏水作用,这可能是导致FgCYP51B-F511L突变体对烯唑醇敏感性增强的原因。     

Geographic distribution and genetic diversity of Fusarium graminearum and F. asiaticum on wheat spikes throughout China

A large number of Fusarium graminearum and F. asiaticum isolates were collected from wheat spikes from all regions in China with a history of fusarium head blight (FHB) epidemics. Isolates were analysed to investigate their genetic diversity and geographic distribution. Sequence characterized amplified region (SCAR) analyses of 437 isolates resolved both species, with 21% being F. graminearum (SCAR type 1) and 79% being F. asiaticum (SCAR type 5). AFLP profiles clearly resolved two groups, A and B, that were completely congruent with both species. However, more diversity was detected by AFLP, revealing several subgroups within each group. In many cases, even for isolates from the same district, AFLP haplotypes differed markedly. Phylogenetic analyses of multilocus DNA sequence data indicated that all isolates of SCAR type 1, AFLP group A were F. graminearum , whilst isolates of SCAR type 5, AFLP group B were F. asiaticum , demonstrating that it is an efficient method for differentiating these two species. Both species seem to have different geographic distributions within China. Fusarium graminearum was mainly obtained from wheat growing in the cooler regions where the annual average temperature was 15°C or lower. In contrast, the vast majority of F. asiaticum isolates were collected from wheat growing in the warmer regions where the annual average temperature is above 15°C and where FHB epidemics occur most frequently. This is the first report of the distribution of, and genetic diversity within, F. graminearum and F. asiaticum on wheat spikes throughout China.     

Pathogenicity of Fusarium graminearum and F. meridionale on soybean pod blight and trichothecene accumulation

Soybean (Glycine max) is the most important crop in Argentina. At present Fusarium graminearum is recognized as a primary pathogen of soybean in several countries in the Americas, mainly causing seed and root rot and pre‐ and post‐emergence damping off. However, no information about infections at later growth stages of soybean development and pathogenicity of F. graminearum species complex is available. Therefore, the objectives of this study were to compare the pathogenicity of F. graminearum and F. meridionale isolates towards soybean under field conditions and to evaluate the degree of pathogenicity and trichothecene production of these two phylogenetic species that express different chemotypes. Six isolates of F. graminearum and F. meridionale were evaluated during 2012/13 and 2013/14 soybean growing seasons for pod blight severity, percentage of seed infected in pods and kernel weight reduction. The results showed a higher aggressiveness of both F. graminearum and F. meridionale species during the 2013/14 season. However, the differences in pathogenicity observed between the seasons were not reflected in a distinct trichothecene concentration in soybean seeds at maturity. Fusarium meridionale isolates showed similar pathogenicity to F. graminearum isolates but they were not able to produce this toxin in planta during the two field trials.     

玉米穗、茎腐病镰孢菌相互关系的血清学研究

运用血清学方法研究了沈阳、河北、北京、吉林4个地区玉米穗、茎腐病镰孢菌在病原学上的相互关系。结果发现:各地区玉米穗、茎腐病串珠镰孢菌(Fusarium moniliforme)具有高度的同源性,亲缘关系近。各地区玉米穗、茎腐病禾谷镰孢菌(F.graminearum)的亲缘关系因地域不同而有差异。沈阳穗、茎腐病禾谷镰孢菌之间差异明显,存在生理分化现象;吉林玉米穗、茎腐病病原物存在较高的相似性,但也有一定的差异;而河北玉米穗、茎腐病禾谷镰孢菌具有高度的同源性。