转cry1Ac和CpTI双基因抗虫水稻对二化螟和大螟的致死效应及田间螟虫构成的影响

 就转cry1Ac＋CpTI双基因抗虫水稻不同生育期对二化螟Chilo suppressalis和大螟Sesamia inferens的室内致死特性及田间螟虫的构成进行了研究。室内测定结果表明，不同生育期转基因水稻对二化螟、大螟都表现明显的致死效应，但水稻生长后期的致死效果降低。转基因水稻对大螟的致死效应显著弱于对二化螟的，其中，二化螟除在齐穗期和成熟期有少量幼虫（0.5%~6.4%）存活到第4天外，其余均在第4天死亡；大螟在两种转基因水稻上的存活率高于二化螟，且少量个体（<1.6%）还能化蛹、羽化，但化蛹率和羽化率均明显低于在非转基因对照上的。早、晚两季水稻的田间调查结果表明，转基因水稻上两种螟虫虫口数量均显著低于相应的非转基因对照品种，转基因水稻上二化螟虫口减退率>99％；大螟虫口减退率相对较低，早、晚稻上有所不同，其中早稻 >93％，晚稻仅44％～64％。转基因水稻上残存螟虫中，大螟所占比例明显上升，推测转基因水稻对两种螟虫致死效应差异可能是其主要原因。     

不同籼稻品种对二化螟和三化螟的抗螟性鉴定

鉴定、评价水稻材料抗螟性是利用材料进行抗螟虫育种的基础。依据海南采集的三化螟卵块接种和本地自然发生的二化螟引起的枯心和白穗,对4个不同抗性水平的材料进行抗螟性鉴定和评价。结果表明,各材料对二化螟和三化螟的抗性具有一致性;A232抗螟性虽不及转肪基因材料的高抗水平,但较其他材料抗性差异显著;利用自然田间发生的螟虫对材料进行抗螟性鉴定,最好是在螟虫种群数量较大时的水稻生育后期,利用白穗率来评价品种抗螟性较理想。     

转基因抗虫水稻研究取得重大突破──我国培育成功“克螟稻”

浙江农业大学培育的转基因抗虫水稻——“克螟稻”目前通过省级签定。这种转基因精对二化螟、三化螟、大螟等七种鳞翅目水稻害害虫具有强大的毒杀作用。室内和田间试验表明,它对多种螟虫的抵抗能力达到百分之百,是螟虫的克星。这个新的水稻品系是由浙江农业大学和血事大建太华大学＃同选啻成功的。研究人员应用生物技术将杀9蛋白基因导入水授胚芽,使植株获得毒杀螟g的能力。因此在水稻生长边搓中,不需喷洒江河农函,就和以避免螟g的危害。鉴定委员会对此项成果终于高度评价,认为“克螟按”近抗惧9的能力和它的转基因遗店稳定性,均居国…     

取食香根草后水稻螟虫对杀虫剂敏感度变化

【目的】香根草能有效诱集水稻螟虫产卵,且孵化的幼虫取食香根草一定时间后死亡,可用于水稻螟虫的田间防控。但田间防治往往是多种防治措施相结合。为了研究取食香根草后的幼虫对常用杀虫剂的敏感度,【方法】利用稻苗浸渍法测定了茚虫威、氯虫苯甲酰胺、多杀菌素、甲氨基阿维菌素、氟虫胺、氰氟虫腙、阿维菌素、毒死蜱8种常用杀虫剂对水稻大螟和二化螟的毒力作用,以及取食香根草后螟虫对这些药剂的敏感度变化。【结果】8种杀虫剂(氰氟虫腙,甲氨基阿维菌素,氯虫苯甲酰胺,氟虫胺,多杀菌素,阿维菌素,茚虫威,毒死蜱)对大螟的LC₅₀依次为1.04,1.40,2.67,3.48,7.59,13.03,16.57,23.28 mg/L;对二化螟的LC₅₀依次为1.94,2.07,4.20,8.93,9.72,17.63,9.51,64.68mg/L。与取食水稻的螟虫比较,香根草饲喂3d后,大螟幼虫对8种药剂的敏感性均有所提高,致死率提高13.3～22.2个百分点,其中,对氯虫苯甲酰胺、多杀菌素、氟虫胺、氰氟虫腙、毒死蜱的敏感度显著提高;而香根草饲喂后的二化螟幼虫对所有测定药剂敏感度均显著提高,致死率提高26.7～33.3个百分点。二化螟幼虫对所有测定药剂敏感度升高更为明显。【结论】初步明确了水稻螟虫取食香根草后对杀虫剂的敏感度有不同程度提高。     

古巴蝇生物学及生态学的初步研究

为了探索古巴蝇防治甘蔗螟虫在广西蔗区应用的可行性,广西甘蔗研究所于2004～2005年从古巴引进古巴蝇并进行了相应研究.结果表明:古巴蝇能寄生二点螟、条螟、黄螟和玉米螟等甘蔗害虫.化蛹率为70%～90%,羽化率在80%～90%.不能寄生桑蚕.能用非自然寄主大蜡螟人工繁殖古巴蝇,平均化蛹率为100.46%,平均羽化率为86.32%.古巴蝇喜欢温暖潮湿,在26～28℃、相对湿度75%～85%时,生长发育最佳,生物学周期为25～40d.接种(寄生)至化蛹为8～10d,蛹期为6～10d,雄蝇寿命3～6d,雌蝇寿命20～30d.0℃以下的低温和42℃以上的高温对古巴蝇的生长发育、化蛹和羽化不利,古巴蝇蛹在8～10℃保存5～10d羽化率不受影响,但蛹期相应延长.本研究对指导广西蔗区应用古巴蝇防治甘蔗螟虫,促进广西蔗糖业可持续发展有着重要意义.     

单季稻大螟防治问题及氯虫苯甲酰胺对大螟白穗防效试验

近年来大螟的数量在局部地区已上升为主要害虫,其种群数量也已超过二化螟。大螟上升主要原因,一是耕作制度多样化与农田生态环境改善有利于多食性大螟的发生;二是大螟发生期早于二化螟,在当前普遍采用长持效药剂,防治间隔时间拉长情况下,大螟容易出现失治漏治;三是当前螟虫主治药剂氟虫腈三唑磷等对大螟防效不理想。为此,笔者进行了新药剂氯虫苯甲酰胺防治大螟药效试验。结果表明,20%氯虫苯甲酰胺对单季晚稻破口期大螟的防效为94%、保穗率71%,显著高于90%杀虫单200 g/667 m2高剂量处理的84.6%、54.7%。同时提出"改变作物布局,集中连片种植,及时清除田边杂草,恶化大螟生存环境,加强测报,适期防治"的防控策略。     

氟虫腈亚致死剂量处理对二化螟和大螟幼虫体内解毒酶系活力的影响

氟虫腈对二化螟Chilo suppressalis (Walker)和大螟Sesamia inferens (Walker)幼虫的LD50值各为0.1749 μg/g和10.1352 μg/g。经氟虫腈亚致死剂量（LD15）处理后,二化螟和大螟幼虫羧酸酯酶（CaE）和谷胱甘肽S 转移酶（GST）的比活力和最大反应速率（vmax）均显著增强,而多功能氧化酶（MFO）则显著降低。二化螟CaE和MFO的米氏常数（Km）经氟虫腈处理后均显著增高,而GST的无显著变化;大螟CaE、GST和MFO的Km均极显著降低。这表明氟虫腈在二化螟和大螟幼虫体内的代谢途径可能存在较大差异,而2种螟虫体内解毒酶对底物亲和力的不同可能导致两者对氟虫腈敏感性的差异。     

转基因抗虫性水稻恢复系选育及特性分析

将优质抗稻瘟病水稻恢复系成恢177与转基因水稻Bt明恢63杂交并回交1次,采用PCR分析、试纸条检测、室内和田间人工接虫鉴定抗虫性,并结合系谱法选择农艺性状,病圃接种鉴定稻瘟病抗性,育成具转基因抗虫性的水稻新恢复系Bt5198。采用离体茎秆法接种二化螟卵块,新恢复系Bt5198和Bt明恢63的幼虫死亡率均为100%。在田间人工接虫条件下,该恢复系对二化螟和三化螟均表现高抗,与4个不育系配制的杂种F1仍保持良好的抗虫性,且杂种优势明显。两年稻瘟病抗性鉴定结果表明,新恢复系Bt5198的叶瘟和颈瘟抗性水平与成恢177相当,明显优于Bt明恢63。Bt5198的种子发芽率和花粉量与成恢177相当,Bt基因导入水稻恢复系不会对种子生活力和制种产量造成显著影响。在无选择标记基因的转基因后代中,结合利用试纸条检测和室内、田间人工接虫鉴定是筛选Bt基因抗虫性的有效方法。     

龙吉稻田稻蛀螟发生为害及螟害株密度零频率估计法

稻蛀螟类是水稻常见害虫,为查明稻蛀螟发生为害情况和探索在一定精度保证前提下简便、快捷地估计螟害株密度的方法,对海南省澄迈县老城镇龙吉村稻田稻蛀螟发生为害进行了系统调查,并利用稻丛螟害株密度m和稻丛螟害零频率P0分别拟合线性函数、二次函数、双曲线函数、指数函数、幂函数、对数函数等常用函数模型及Gerrard-Chiang模型和Wilson模型。结果表明,龙吉稻田发生的稻蛀螟种类为三化螟[Scripophaga incertulas(Walker)]和大螟[Sesamia inferens(Walker)],其中早稻以大螟为主,晚稻则以三化螟占优;早、晚稻的螟害株密度从分蘖后期至乳熟期均呈先上升而后下降趋势,晚稻分蘖后期的螟害株密度明显高于早稻同生育期的,而早、晚稻的螟害株密度在孕穗期、抽穗期和乳熟期等同生育期间的差异不显著;用螟害零频率估计早、晚稻和早-晚稻螟害株密度的最优模型分别为Gerrard-Chiang模型m=1.164 9(-ln P0)1.045 4、双曲线函数模型m=-0.943 5+0.951 3/P0和m=-0.952 5+0.958 3/P0。应用这些模型在相应稻季可根据三化螟和大螟为害的零频率便捷、有效地估计螟害株密度。     

高温及覆土逆境对茶尺蠖蛹羽化的影响

茶尺蠖是茶树重要害虫,为了全面了解环境对茶尺蠖蛹的影响,在室内通过5个温度（24、26、28、30、32℃）和4个（0、1、2、4 cm）覆土处理茶尺蠖蛹,观察茶尺蠖蛹羽化情况,探讨温度和覆土逆境环境对茶尺蠖蛹的影响。结果表明,在24～32℃温度范围内,随着温度的升高,蛹的发育历期明显缩短,同时也对羽化率产生显著影响,羽化率随着温度的升高呈现升高后降低的趋势;26℃羽化率最高为82．12％,26℃后处理温度越高,羽化率越低;高温使雌蛾蛹早于雄蛹羽化,雌雄比例上升。覆土对茶尺蠖蛹羽化有明显影响,随着覆土深度加深,茶尺蠖蛹的羽化率呈现升高后降低的趋势,在覆土深度4 cm 时,茶尺蠖羽化率最低,为33．33％,所以,可以在茶尺蠖化蛹高峰期采用深耕翻土方式,对减轻其为害具有一定的作用。覆土对茶尺蠖开始羽化的时间无显著影响。     

Comparison of stem borer damage and resistance in semidwarf Indica rice varieties and prototype lines of a new plant type

The rice (Oryza sativa L.) “new plant type” (NPT), currently under development at the International Rice Research Institute, Philippines, differs in genetic background and plant architecture from the semidwarf Indica varieties that now predominate in tropical lowland areas. The NPT is derived from tropical Japonica germplasm and has fewer and larger stems and panicles than do semidwarf Indica varieties. We compared stem borer damage and resistance in NPT lines and semidwarf Indica varieties under field and greenhouse conditions. Stem borer damage in field plots of the NPT lines IR65564 and IR68011 was higher than in plots of the Indica varieties IR64 and IR72 during the 1999 dry season but not the wet season. In both seasons, IR68011 had higher densities of egg masses of the striped stem borer (SSB, Chilo suppressalis) than did the other three entries. There were no consistent differences among entries in density of egg masses of the yellow stem borer (YSB, Scirpophaga incertulas). In the 2000 wet season, stem borer populations were low, but SSB egg masses were found only on IR68552-100, the only NPT line in the experiment. In all three seasons, NPT lines had higher proportions of SSB larvae and pupae in stems after harvest, and lower proportions of YSB, than did Indica varieties. In artificially infested field cages, SSB larval survival was highest on reproductive stage plants of IR68011 in the 1999 dry season and there was a trend of higher YSB adult weight on IR68011 in the 1999 dry and wet seasons. Three NPT lines and three Indica varieties evaluated under greenhouse conditions showed no consistent differences in resistance to either stem borer species, as measured by percent survival from egg to adult and female development time and weight. The lack of consistent differences in stem borer survival and development between the NPT lines and Indica varieties was contrary to the expectation that the morphology of the NPT would render it more susceptible to stem borers. Our results indicate that NPT lines are not consistently or strongly more susceptible to stem borers than are improved Indica varieties and suggest that ovipositional attractiveness to SSB is a factor contributing to higher stem borer damage to some NPT lines.     

Rice striped stem borer, Chilo suppressalis (Lepidoptera: Pyralidae), overwintering in super rice and its control using cultivation techniques

Super rice has the potential to deliver very high yields but is also susceptible to attack by the striped rice stem borer, Chilo suppressalis. In this study, surveys and field trials were performed to examine this problem and efficient ways were found to lower the borer’s population density. It was found that larger super rice plants provided more refuges for borers to evade insecticide contact and had a longer growth period allowing borers to complete their larval development in an intact environment. The current cultivation regime was shown to favour outbreaks of borers. Super rice is harvested leaving tall field stubbles until the following growing season, thus providing food and cover in which borers may successfully overwinter. We found that borer larvae were distributed to a greater height in the plants of super rice than in common rice, making control through agricultural operations more feasible. Burning fields after harvest, which killed 84.5% of borers, seemed the best remedy, though this practice is forbidden in China for ecological reasons. Leaving short stubbles followed by appropriate treatment of the rice straw killed 74.0% of the borer population. In addition, spring irrigation after the pre-pupation dispersal movements of borers killed more than half of the overwintering population. Pre-winter rotary tillage had little effect on borer numbers but enhanced the population reduction effect of irrigation the following spring. Based on the results obtained, efficient control of borers on super rice can be achieved by harvesting leaving short stubbles, followed by rotary tillage and spring irrigation. This regime can reduce the borer population by more than 98%, minimising chemical use and maximising use of a reduced agricultural workforce.     

Breeding and Characterization of a New Rice Restorer Line Containing Bt Gene

Bt5198, a new rice restorer line containing Bt gene, was developed from the cross and backcross of the elite restorer line Chenghui 177 with Bt Minghui 63, a transgenic Bt restorer line. The inbred lines were evaluated using PCR amplification, test paper evaluation, insect resistance evaluation in both the laboratory and paddy fields, nursery evaluation of rice blast resistance and pedigree selection of agronomic traits. Larval mortalities on Bt5198 and Bt Minghui 63 were 100% when rice culms were inoculated with the eggs of the striped stem borer (SSB) in the laboratory. Bt5198 was highly resistant against SSB and the yellow stem borer (YSB) under field conditions. The F₁ hybrids derived from Bt5198 and four cytoplasmic male sterile (CMS) lines were also highly resistant to SSB and YSB and had a significant heterosis. Two-year evaluation of rice blast resistance confirmed that the resistance levels of Bt5198 to leaf blast and neck blast were similar to those of Chenghui 177 and significantly better than those of Bt Minghui 63. Seed germination ability and pollen yield of Bt5198 were similar with Chenghui 177, suggesting that the introduction of the Bt gene into the new restorer line had no significant effects on seed vitality or the yield of seed production. To identify the presence of the Bt gene, it was effective to combine test paper examination with the evaluation of insect-resistance, both in the laboratory and under field conditions.     

水稻抗二化螟特性离体稻株鉴定技术

提出了一套规范的水稻抗二化螟离体稻株鉴定技术。该项技术克服了以往鉴定方法难保鲜、操作烦琐、试虫易逃逸等问题,准确可靠、操作易规范,适用于常规水稻和转基因水稻抗二化螟特性鉴定和评价。     

Abundance and Spatial Dispersion of Rice Stem Borer Species in Kahama,Tanzania

Species diversity, abundance, and dispersion of rice stem borers in framer’s fields were studied in four major rice growing areas of Kahama District. Stem borer larvae were extracted from the damaged tillers in 16 quadrants established in each field. Adult Moths were trapped by light traps and collected in vials for identification. Results indicated the presence of Chilo partellus, Maliarpha separatella, and Sesamia calamistis in all study areas. The most abundant species was C. partellus (48.6%) followed by M. separatella (35.4%) and S. calamistis was least abundant (16.1%). Stem borers dispersion was aggregated along the edges of rice fields in three locations (wards) namely: Bulige, Chela, and Ngaya. The dispersion in the fourth ward, Kashishi was uniform as established from two of the three dispersion indices tested. Further studies would be required to establish the available alternative hosts, the extent of economic losses and the distribution of rice stem borers in the rest of the Lake zone of Tanzania.     

水稻和茭白二化螟蛹形态特征的数值分析

通过对水稻、茭白二化螟（Chilo suppressalis）蛹进行形态特征的数值分析,结果表明水稻二化螟、茭白二化螟蛹形态的几个指标存在差异,但其不能截然分开。用主成分分析并绘制二维排序图,发现水稻二化螟、茭白二化螟交迭在一体。     

水稻植株在二化螟为害后的生理变化

研究了不同类型水稻品种在二化螟为害后植株体内的一些生理变化,包括叶绿素含量、根系活力和钾元素吸收能力。不同水稻品种在主茎受二化螟为害形成枯心后,分蘖的叶绿素含量均降低,但与健康植株相比无显著差异。常规杂交稻汕优63和超级杂交稻两优培九在主茎枯心过程中根系活力显著增强,而粳稻秀水11枯心后根系活力反而显著下降。采用86Rb标记示踪原子法研究了在二化螟为害后水稻根系对土壤中钾的吸收能力的变化,发现秀水11主茎枯心24 h和48 h后分蘖中铷的含量比健康植株分别降低了5.23%和47.5%,说明对钾的吸收能力下降,而汕优63和两优培九分蘖中铷的含量分别比健康植株增加了2.91%和14.36%、21.3%和15.9%,即对钾的吸收能力提高。     

规模化稻鸭生产对早稻病虫害变化规律及经济效益的影响

通过大田试验研究了规模稻鸭生态种养系统中水稻病虫害的消长变化规律及其经济效益。结果表明：规模稻鸭生态种养（IF）水稻二化螟、稻纵卷叶螟、稻飞虱和稻叶蝉平均虫量较水稻单一种植（CK）分别下降54．4％,48．8％,73．6％和96．1％,纹枯病和稻瘟病病株率分别降低78．9％和48．5％;较常规稻鸭生态种养（CF）水稻二化螟、稻纵卷叶螟、稻飞虱和稻叶蝉量分别下降18．2％,9．5％,7．0％和0．82％,纹枯病病株率降低35．5％,稻瘟病病株率升高8．0％。规模稻鸭生态种养稻飞虱和二化螟对水稻危害株率比常规稻鸭生态种养分别降低52．9％和6．9％。试验还表明,规模稻鸭生态种养系统中水稻二化螟、稻纵卷叶螟、稻飞虱虫峰迟现,持续危害时间短;纹枯病蔓延危害期缩短10～14d;水稻有效穗数、穗粒数增多,千粒重增加,空壳率降低,产量最高。规模稻鸭生态种养较常规稻鸭生态种养和水稻单一种植分别增收1024．32,1370．61元／hm2,增幅44．47％和70．03％。因此,规模稻鸭生态种养可以实现对水稻病虫害的生态控制,且经济效益显著提高,对于提升我国现代农业生产实践具有重要意义。