21个甘蔗品种对螟虫抗性鉴定与评价

【目的】明确甘蔗品种对甘蔗螟虫的抗性,以期为抗虫品种推广应用和抗性基因发掘奠定基础。【方法】通过自然种群接虫方法,研究不同甘蔗品种苗期和生长中后期螟害水平。运用聚类分析方法,综合评价不同甘蔗品种对螟虫的抗性。【结果】不同甘蔗品种对螟虫危害造成的螟害枯心率、螟害株(节)率和株虫孔数等存在显著差异。21个甘蔗品种分为4个抗性等级。第1级1个品种(ROC10),螟害枯心率、螟害株(节)率、株虫孔数低;第2级包括4个品种(粤糖60号、柳城05-136、桂糖29号、粤糖55号),表现为螟害枯心率低、螟害株(节)率中等、株虫孔数中等;第3级包括9个品种(福农38号、桂糖31号等),表现为螟害枯心率中等、螟害株(节)率中等、株虫孔数中等;第4级包括7个品种(福农39号、德蔗03-83等),表现为螟害枯心率、螟害株(节)率、株虫孔数高。【结论】甘蔗品种和生育期影响螟虫的发生,不同品种对甘蔗螟虫抗性水平存在差异。     

沟金针虫为害小麦的损失分析及防治指标研究

沟金针虫为害小麦的损失主要体现在两个方面,一是小麦返青拔节期为害,使小麦茎蘖死亡。穗数减少。二是拔节后为害,形成白穗、虫伤株,使小麦穗粒数减少,千粒重下降。1～5级虫伤株的损失率分别为1％、6.3％、30.7％、33.4％和57.3％。虫口密度与产量损失率呈直线回归关系,方程为y=-2.8901+19.3318x,在亩产200～250kg水平下,防治指标为4～5头/m~2。     

两种主要蔗螟的初步研究

粤东地区的甘蔗螟虫有二点螟Chilo infuscatellus Snellen、条螟Proceras venosatus Wk.、黄螟Encosma schistaceana snellen、台湾稻螟Chilotraea auricilia Dudgeoa和大螟或称紫螟Sesamia inferens wk.五种。其中以前三种分布最广,为害则以二点螟和条螟最烈,常因这两种蔗螟为害而造成枯心、蛀节、枯茎和断茎,并因螟害而引起赤腐病,甚至整株枯死,影响蔗糖的产量和质量。根据我们1957—1963年调查;旱地甘蔗二点螟为害枯心苗率一般哒8.4％—39.6％。条螟被害节率达4.7％—12.4％,被害全株枯死率达5％—8.45％,蛀节风折率达6.6％—8.93％,损失很大。兹就二点螟和条螟的生活习性,形态特征     

湖北江汉稻区优质香稻上二化螟的为害特性

研究了二化螟Chilo suppressalis(Walker)对优质香稻鄂香1号和武香988及优质常规中稻鄂中5号的田间为害特性。结果显示,1代二化螟危害造成的枯心苗数优质香稻略低于优质常规中稻。2代二化螟危害造成的枯孕穗和白穗优质香稻鄂香1号低于常规中稻,平均每15丛7.91株。田间剥查发现优质香稻中4~5龄2代二化螟所占百分比高于常规中稻,武香988中2代二化螟蛹所占比例高于常规中稻,达46.51%。3代二化螟量优质香稻低于常规中稻。结果说明香稻受二化螟的危害集中在2代,因而香稻二化螟的防治应注意消灭1代老熟幼虫和2代幼虫。     

台湾稻螟性外激素在测报及防治上的应用

<正> 台湾稻螟Chilo auricilius Dudgeon分布于我国台湾、四川、福建、广东、广西、云南等省区。一般报道认为该虫主要危害水稻,但在滇西的德宏州5县1市,是甘蔗和水稻的重要害虫。为害甘蔗、水稻造成枯心、白穗及螟害节,严重影响甘蔗产量和质量。经调查为害甘蔗的     

棉铃虫为害水稻

近年来笔者从事水稻纹枯病研究工作,每3～5天即在稻田调查。1996年8月中下旬发现有虫暴露在水稻植株上为害,经鉴定确认为棉铃虫He伽ovefpaa七Wigero－－xxx－xxuo。此类报道未见,故简报如下。（l）水稻品种为粳稻（武有粳3号）;（2）调查稻田距棉田200～500m;（3）稻田中棉铃虫幼虫l～6龄均有;M幼虫均在稻株顶叶或穗部,水稻未抽穗时,幼虫啮食嫩叶叶肉,少数食成缺刻,抽穗后,幼虫多数爬至穗部咬食灌浆、乳熟稳粒;（5）千株有虫0～5头不等。1996年本市四代棉铃虫在棉田落卵量为1556粒／百株,属特大发生。笔者分析认为稻田中棉铃…     

不同世代螟害对春玉米“农大7号”产量损失的影响

近年来,国内在螟害对玉米产量损失影响的研究方面取得了很大进展。吴维均等(1963)以人工接卵方法研究了夏玉米“小黄”品种上穗期螟害对产量的影响,证明乳熟到腊熟阶段内,螟害对产量的影响极小,单株1虫的损失百分率仅0.89％(约折合每亩4斤)。以同样方法研究春玉米“农大7号”穗期螟害对产量的影响表明,开花授粉时接种者,对产量有一定影响,根据虫口密度与产量的回归式求出单株平均每增加1头幼虫的损失率为2.7％(约折合每亩22斤);而在乳熟中期接种者,则无影响,单株平均有虫10头以上的产量并不比单株有虫0.35头的产量为低。邱式邦等(196)在盆栽王米上分期接种结果,也证明心叶期接种者对产量的影响显著大于灌浆期接种的处理,后者在单株平均有虫3.5—15.1头时,产量与对照并无显     

三化螟种群阶段性变动的数量分析

通过1969～1990年三化螟年诱虫数序列的游程总数检验,判断三化螟种群存在实质性下降。按相同方法对各世代间增殖率的检验证明,第1代成虫至第2代成虫期间,是引起种群阶段性变动的唯一时期。根据年代段之间“百卵螟害率”(螟害率％÷卵密度×100)的比值,推算出防治效果的提高和第2代白穗史源田的减少,对第2代卵至第3代卵间增殖率下降的作用,分别占67.1％和32.9％。     

棉铃虫老熟幼虫有效越冬虫量的分析

通过从棉田和玉米田采回的第 4代老熟幼虫的化蛹率和羽化率观察 ,发现棉田和玉米田的老熟幼虫化蛹率分别为 65%～ 83 0 5%和 55%～ 80 % ,其化蛹后的羽化率分别为 1 0 %～ 87%和 1 3 %～77% ,而且 2种寄主作物间无显著差异。由此进一步分析了棉田和玉米田老熟幼虫的有效越冬虫率和有效越冬虫量 ,作者认为 8月 3 1日至 9月 1 0日是棉铃虫老熟幼虫有效越冬虫量的主要来源期 ,且棉田显著高于玉米田 ,构成了第 2年棉铃虫种群发生基础。     

水稻株高构成因素的QTL剖析

利用水稻籼粳杂交 (圭 6 30× 0 2 42 8) F1 的花药离体培养建立的一个含 81个 DH家系的作图群体 ,对水稻株高构成因素 (穗长、第 1节间长、……、第 5节间长 )进行基因定位。DH群体中株高构成因素均呈正态分布。相邻的构成因素间呈极显著的正相关 ,而相距较远的构成因素间的相关较弱或不显著。采用 QTL(Quantitative trait lo-cus)分析 ,定位了影响株高构成因素的 6个 QTL:qtl7同时影响穗长和第 1、2、3节间长 ,qtl1 和 qtl2 同时影响第 4和第 5节间长 ,qtl1 0 a和 qtl1 0 b仅影响第 1节间长 ,qtl3 仅影响第 3节间长。采用 QTL 互作分析 ,检测到 19对显著的互作 ,每个构成因素受 2个或 2个以上的 QTL 互作对的影响。并且还发现 ,同一个 QTL 互作对可能影响不同的性状 ,以及一个 QTL 可以分别与不同的 QTL 产生互作而影响同一个性状或影响不同的性状 ,但总的看来 ,加性效应是主要的。这些结果揭示了株高构成因素间相关的遗传基础 ,在水稻育种中运用这些 QTL 将有助于对株高 ,以及对穗长和上部节间长度进行精细的遗传调控。     

杀虫剂不同处理对二化螟为害、防治效果及水稻产量的影响

近年来,二化螟发生出现各代均偏重或大发生的新特点。为探索杀虫剂防治二化螟的新策略,采用田间小区试验在早晚稻田中分别研究5%氟虫腈加25%灭.水胺的不同施药时期和次数对二化螟幼虫的为害和防治效果及对水稻产量的影响。在试验地,二化螟第1和第2代发生在早稻田,第3和第4代发生在晚稻田。试验结果表明,在第1和第3代二化螟幼虫孵化高峰施药1次、隔10d再施药1次对早稻田和晚稻田的幼虫防效显著,分别达到了92.4%和92.6%。在早、晚稻田分别发生的第1和第3代2龄幼虫高峰期施药1次、同时在次代孵化高峰期再施药1次,均可显著降低虫伤株率和白穗株率,提高保穗效果,并显著提高单位面积上的水稻产量(3.98%~4.20%)。因此,对第1至第4代二化螟幼虫均进行1次药剂防治是二化螟各代均大发生的新形势下的防治策略。     

Most susceptible stage of rice panicle development to Oebalus pugnax (Hemiptera: Pentatomidae)

Oebalus pugnax (F.) (Hemiptera: Pentatomidae) damage to rice, Orya savita L., reduces rough and head rice yields, and grain quality. O. pugnax feeds on developing kernels, introducing pathogenic fungi and causing a discoloration of the grain known as "peck." The objective of this study was to determine the stage of rice panicle development most susceptible to O. pugnax attack. During 2005 and 2006, in greenhouse and field experiments, rice plants were caged at the boot stage and then infested with adult or nymphal O. pugnax. Plants were infested during one of three stages of panicle development: heading, milk, or soft dough. Insects were allowed to feed on the plants for the duration of each stage and then killed. After maturation, panicles were harvested, and grain was hulled and milled. Grain weight, percentage of pecky grain, and percentage of whole grain after milling were recorded. No differences were found in the weight of rough, brown, or milled rice infested with O. pugnax during different stages of panicle development. Number of filled grains per cage was not affected by O. pugnax, and number of empty grains per cage was affected in two of four experiments. Higher percentage of peck was found in grain from panicles infested during dough and milk than in grain from panicles infested during heading. Adult O. pugnax caused higher percentage of peck than nymphs in all stages of panicle development. An inverse relationship was found between percentage of peck and percentage of whole grain weight only in one of the experiments.     

Population dynamics and effects of Oebalus ornatus (Hemiptera: Pentatomidae) on rice yield and quality in southwestern Colombia

Field experiments were conducted from 1989 to 1992 to determine the effects of Oebalus ornatus (Sailer) on Cica 8 rice, Oryza sativa L., yield and to study the population dynamics of the insect. The effect of O. ornatus was measured for seven population levels (0, 2, 3, 4, 8, 12, and 24 sexed pairs per 20 panicles) at three stages of grain development (flowering, milk, and soft dough stage). Insect feeding during the flowering and milk stages of grain development caused more damage than feeding during the soft dough stage. The action threshold was calculated to be 14 O. ornatus adults per square meter for the flowering and milk stages and 67 for the soft dough stage of grain maturity. Population densities that would reduce rice yield in southwestern Colombia were not observed during the 3 yr of the study.     

南方水稻黑条矮缩病毒介体昆虫白背飞虱的传毒特性

白背飞虱Sogatella furcifera(Horváth)为传播南方水稻黑条矮缩病病毒(SRBSDV)的媒介昆虫,阐明其传毒特性将有助于了解南方水稻黑条矮缩病的发生流行规律和建立相应的防治方法。本研究通过RT-PCR技术测定了白背飞虱的传毒参数。结果表明,白背飞虱初孵若虫、3龄若虫、5龄若虫、长翅型成虫和短翅型成虫的最短获毒时间分别是11、6、3、2和2min,最长获毒时间分别是19、12、9、8和8min。在26℃时,SRBSDV在不同虫态(初孵若虫、3龄若虫、5龄若虫、长翅型成虫和短翅型成虫)的白背飞虱体内的循回期分别是7～11、5～8、3～7、4～8和3～6d。5龄若虫、长翅型和短翅型成虫在三叶一心稻苗的最短接毒时间为4、5和6min,最长接毒时间为8、10和11min;它们在分蘖初期稻苗上的最短接毒时间分别是5、7和7min,最长接毒时间分别是10、12和12min。白背飞虱获毒后可终身传毒,但不能经白背飞虱卵传毒,单虫最多传毒株数为87株,平均传毒48.3±0.8株。可见,该虫具有较强的获毒能力和传毒能力,秧苗易感染SRBSDV。因此,在防治上应尽量清除田间SRBSDV毒源植物,减少白背飞虱获毒的机会,在秧田期和移栽初期应重点防治飞虱。     

Attractiveness of stages of rice panicle development to Oebalus pugnax (Hemiptera: Pentatomidae)

Greenhouse experiments were conducted during 2004 and 2005 with male and female Oebalus pugnax (F.) (Hemiptera: Pentatomidae) caged on rice plants at different stages of panicle development with the objective of determining the most attractive stage to O. pugnax. Field-collected insects were released inside cages containing potted plants and observed during morning and afternoon hours for 5 d. Results showed that attractiveness of male and female O. pugnax to plants with panicles at milk and soft dough stages was greater than plants at preheading and heading stages. Preheading plants were the least attractive to the insects, confirming field observations. Results imply that insecticide applications during the preheading stage are likely ineffective and that monitoring efforts during the milk and soft dough stages of panicle development should be intensified.     

云南主要蔗龟的生物学研究

蔗龟是云南甘蔗上的1种主要地下害虫。经1987～1991年系统研究,大等鳃金龟、暗褐鳃角金龟、突背蔗金龟是云南危害甘蔗的优势种。前两种主要以幼虫为害根部,造成减产,严重的无收;第三种主要以成虫咬食蔗苗基部,造成枯心死亡。3种均1年发生1代。成虫有趋光性,初孵幼虫喜食已腐烂的有机质。在沙壤土、粘土较重土壤虫口较多;宿根年限越长受害愈重。蔗稻轮作;7～8月雨季用水淹灌蔗地;结合松、培土每亩施用3％甲基异柳磷颗粒剂4～5kg,防治效果达90％左右。     

Molecular,biochemical and bioassay based evidence of lower allelopathic potential in genetically modified rice

This study examines allelopathic potential of genetically modified rice. The experiment was conducted on two isogenic lines Bacillus thuringiensis (Bt) and non-Bacillus thuringiensis (non-Bt). Both isogenic lines have same allelopathic ability before insect feeding and after limited insect feeding (Spodoptera litura) non-Bt rice genotype demonstrates more allelopathic potential. The S. litura cannot feed Bt rice genotype. The role of shoot herbivory in allelopathic induction is further supported when Bt plants also exhibited higher allelopathic potential after insect regurgitant application to the damaged leaves. Allelopathic potential was assessed through several methods after treatments of mechanical damage, insect feeding and insect regurgitant application to damaged rice leaves. Rhizosphere soil and leaf leachates of non-Bt rice cultivar exhibited higher allelopathic potential on lettuce and barnyard grass after herbivore feeding. Enzyme activities (PAL and C4H) responsible for biosynthesis of phenolic compounds and their concentration were significantly higher in non-Bt plant after herbivore feeding and attain the same level in Bt plants after insect regurgitant application to damaged leaves. Similarly, genes (OsPAL and OsCYC1) responsible for biosynthesis of allelopathic compounds showed high expression in non-Bt plants after herbivore feeding. Our results indicate that herbivore feeding enhance rice allelopathic potential and no insect feeding as incase of Bt plants may reduce allelopathic potential of genetically modified rice.     

Light-regulated overexpression of an Arabidopsis phytochrome A gene in rice alters plant architecture and increases grain yield

The phytochromes are a family of red/far-red light absorbing photoreceptors that control plant developmental and metabolic processes in response to changes in the light environment. We report here the overexpression of Arabidopsis thaliana PHYTOCHROME A (PHYA) gene in a commercially important indica rice variety (Oryza sativa L. Pusa Basmati-1). The expression of the transgene was driven by the light-regulated and tissue-specific rice rbcS promoter. Several independent homozygous sixth generation (T₅) transgenic lines were characterized and shown to accumulate relatively high levels of PHYA protein in the light. Under both far-red and red light, PHYA-overexpressing lines showed inhibition of the coleoptile extension in comparison to non-transgenic seedlings. Furthermore, compared with non-transgenic rice plants, mature transgenic plants showed significant reduction in plant height, internode length and internode diameter (including differences in cell size and number), and produced an increased number of panicles per plant. Under greenhouse conditions, rice grain yield was 6–21% higher in three PHYA-overexpressing lines than in non-transgenic plants. These results demonstrate the potential of manipulating light signal-transduction pathways to minimize the problems of lodging in basmati/aromatic rice and to enhance grain productivity.     

虫压胁迫对抗虫转基因水稻生长发育及产量性状的影响

在大田条件下,以转基因抗虫水稻Bt63、R1和R2及非转基因水稻汕优63(对照)为材料,设置高、低两种虫压环境条件,研究虫压胁迫对转Bt抗虫基因水稻生长发育及产量相关性状的影响.结果表明： 抗虫水稻在虫压胁迫条件下可充分体现出外源基因的抗性特点.在高虫压条件下,3种转Bt基因水稻受螟虫危害程度远低于对照植株,株高、分蘖数、地上部鲜质量、穗长、穗质量、单株穗数、单株实粒数、实粒质量、结实率、千粒重等生长发育和产量指标均高于对照,但仅株高、分蘖数和穗长3个指标与对照有显著差异.因此,抗虫外源Bt基因的引入对水稻结实性不会产生负面效应,高虫压胁迫条件对抗虫转基因水稻产量的影响较小.