Monitoring of Insecticide Resistance and Genetic Analysis of Triazophos Resistance in Chilo suppressalis (Lepidoptera: Pyralidae)

During 2001 and 2002, insecticide resistance in the fourth instar larvae of striped stem borer (Chilo suppressalis), which were collected from Zhejiang, Jiangsu, Anhui and Jiangxi provinces in China, was monitored using topical application method. Low level of resistance to fipronil (6.5-fold) was detected for the first time in RA (Rui’an) population from southeast Zhejiang, but the other six populations tested remained susceptible to this recently introduced insecticide. No resistance to abamectin had been found after examining six populations from Zhejiang, Jiangsu and Anhui provinces. Resistance to triazophos was monitored in ten populations from the four Provinces, and very high level resistance(163.1-fold) was found in RA population, moderate (18.2-fold) in WZ (Wenzhou, Zhejiang Province) population, and low (6.7- to 9.7-fold) in populations of CS (Changshu), XS (Xishan) and JT (Jintan) from south Jiangsu, whereas the other five populations were susceptible. All the nine populations monitored were resistant to monosultap with varying degree, i.e. high level (113.7- and 57.6-fold, respectively) of resistance in RA and YF (Yifeng, Jiangxi Province) populations, moderate (11.0- to 29.7-fold) in WZ, CS, JT and TH (Taihu, Anhui Province) populations, low (6.7- and 7.5-fold, respectively) in XY (Xinyang, Jiangsu Province) and XS populations, and the lowest (3.7-fold) in GY (Guanyun, Jiangsu Province) population. Inheritance of resistance in triazophos selected strain Rts was studied through reciprocal cross and backcross experiments. The preliminary results indicated that inheritance of triazophos resistance in Rts strain was incompletely dominant, with degrees of dominance being 0.46 and 0.68 for reciprocal crosses, and that the resistance was controlled by a major gene, though minor modifying gene(s) might be involved.     

Resistance of transgenic rice pure lines to brown planthopper

Brown planthopper (Nilaparvata lugens, BPH) is one ofthe most damaging rice insect pests. Recent studies showedthat lectin (GNA), coded by the gna gene from snowdrop(Galanthus nivalis ) was toxic to BPH in artificial diet as-say (Powell et al, 1993, 1995). Here we report the des de-velopment of homozygous transgenic rice lines contained the gna gene and the BPH bioassay test of the homozygous lines.Mature seed-derived callus of japonica rice Fyi 105was bombarded with 2 plasmids, pWRG15…     

Resistance of Xanthomonas oryzae pv. oryzae to saikuzuo

Saikuzuo (N, N'-methylene-di (2-amino-5-sulfurhydrogen-1, 3, 4-thiodiazole)) a good bactericideagainst rice bacterial blight disease, has been usedin China for more than 20 years. In this study,the sensitivity of X. oryzae pv. oryzae (Xoo) tosaikuzuo was tested in vitro and in vivo. Seventy-seven and 11 isolates were collected from Hexian,Anhui Province, and Liuhe, Jiangsu Province, re-     

Changes in Methamidophos Resistance and Fitness of Hybrids in Different Strains of Nilaparvata lugens

A resistant strain selected successively in the laboratory for 17 generations had 198.63-fold resistance to methamidophos. The resistant levels and fitness of progenies from the resistant strain and susceptible strain or field population were closer to those of the resistant strain than those of the susceptible strain or field population. The changes in the resistant levels of the hybrid were propitious to the resistance development, however, the changes of the fitness went to the contrary. The effects of the migration on the development of methamidophos resistance in Nilaparvata lugens were discussed in the aspects of the migration of Nilaparvata lugens, the resistant levels of progenies and the changes of the fitness.     

Different Hypotheses for Resistance Loss of Rice Varieties to Magnaporthe oryzae

It is widely believed that a rice variety loses its resistance to rice blast after three to five years in commercial production due to the emergence of new Magnaporthe oryzae pathotypes(or physiological races)(Ou,1985).However,we believe that a resistant rice variety loses its resistance to M.oryzae not due to the emergence of new physiological races.We propose that pathogenic physiological races already exist in the natural environment,serving as potential physiological races.It is only because of the lack of appropriate environmental conditions,particularly the lack of a suitable rice host,on which such a race is unable to propagate widely and exists as an inferior race.However,when there is an appropriate rice host,the potential pathogenic physiological race can quickly proliferate to become the dominant physiological race,thus leading to the loss of blast resistance in resistant rice varieties.     

Detection of Sensitivity and Resistance Variation of Magnaporthe grisea to Kitazin P,Carbendazim and Tricyclazole

One hundred and twenty-nine isolates of Magnaporthe grisea from Guangdong, Guangxi, Anhui and Jiangsu provinces of China were tested for resistance frequency to kitazin P and carbendazim, respectively by the distinctive concentration method. The resistance frequency of the isolates to kitazin P which had not been used in practice for about ten years was as high as 79.1%, and only one carbendazim-resistant isolate was detected in Gaoyao, Guangdong Province (with a frequency of 0.78%). Meanwhile, the minimum inhibition concentration (MIC) of hyphal melanization was adopted to detect the sensitivity of M. grisea to tricyclazole. There existed several different degrees of sensitivity to tricyclazole in the melanin biosynthesis of M. grisea, but no relationship was found between these MIC values completely inhibiting melanization in hyphae and the EC50 values of tricyclazole against rice blast tested in vivo. After the isolates were induced by chemical taming or UV irradiation in laboratory, kitazin P-resistant and carbendazim-resistant mutants were recovered by both the methods, but none of tricyclazole-resistant mutant was obtained.     

Could the Supply of Boron and Zinc Improve Resistance of Potato to Early Blight?

The adequate supply of boron (B) and zinc (Zn) can improve the structural integrity and permeability of cell membranes, which is a defence mechanism against fungi infection. A greenhouse experiment was conducted to investigate the effect of the application of B and Zn on plant growth and the incidence and severity of potato early blight, a destructive foliar disease of potato crop caused by Alternaria grandis E.G. Simmons. Potato plants (Solanum tuberosum L. cv. Ágata) were grown in 11-l pots filled with sandy soil, unfertilized or fertilized with 5 mg kg^?1 B and 5 mg kg^?1 Zn (either alone or in combination). Potato plants were inoculated with isolates of Alternaria grandis at 40 days after planting. Early blight incidence and severity were evaluated visually 7 days after inoculation with A. grandis isolates. Disease incidence ranged from 16 to 41% infected leaves, and was significantly highest in the treatment with the application of B, followed by the control, and lowest with application of Zn and B + Zn. Early blight severity ranged from 2.5 to 25%, and was significantly higher in the unfertilized treatment than in those fertilized with Zn either alone or in combination with B. These findings suggest that Zn plays a critical role in potato tolerance to early blight and should be considered as a preventive measure in the disease management plan, since application of zinc reduced the incidence and severity of potato early blight. However, the physiological basis of this remains unknown.     

Resistance of Oryza minuta to Nilaparvata lugens (Stl)

Evaluation of O. minuta for the re-sistanee to the brown planthopper(BPH), Nilaparvata lugens (Stal)was carried out by using ModifiedSeedbox Screening Technique(MSST). Based on the significantdifferences between O. minuta,E13-9, and the susceptible checkvariety, TN1, the resistance of O.minuta to BPH was determined byusing a series of resistance indices     

Improvement of Resistance to Bacterial Blight by Marker-Assisted Selection in a Wide Compatibility Restorer Line of Hybrid Rice

4183 is a promising wide compatibility restorer line with good grain quality. Its hybrid rice Shuangyou 4183 (Shuangjiu A/ 4183) was registered in Anhui Province in 2003. However, the line and its hybrid rice are susceptible to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). R4183 carrying Xa21 was developed to improve bacterial blight resistance of 4183 through introducing the broad-spectrum resistance gene Xa21 by marker-aided selection. R4183 had similar level of bacterial blight resistance to IRBB21, the resistant donor, while maintained the wide compatibility, restoring ability and other good economic traits of the recurrent parent 4183. Critical issues on improvement of bacterial blight resistance of hybrid rice and breeding strategies were also discussed.     

水稻种质资源抗灰飞虱评价及抗性机制分析

通过改进的苗期集团筛选法,对138份水稻种质进行了抗灰飞虱鉴定与评价。筛选出对灰飞虱具有不同程度抗性的材料25份,占总鉴定材料的181%,其中高抗种质2份,抗性种质9份,中抗材料14份,粳稻品种明显比籼稻感虫。对部分材料进行的排驱性、抗生性试验及相关分析表明,Rathu Heenati(RHT)、Mudgo、Kasalath和IR36对灰飞虱具有强的排驱性和抗生性,其抗性水平与这两种抗虫机制密切相关;道人桥、羊毛谷的抗生性强,但排驱性弱,其主要抗虫机制表现为抗生性;Dular、ASD7和密阳23对灰飞虱具有较强的排驱性和抗生性,表明排驱性和抗生性是这3个品种的重要抗性类型;DV85具有较强的排驱性,但抗生性较弱,窄叶青8号和鬼衣谷具有中等水平的抗生性和排驱性,推测这3个材料具有较好的耐害特性。中抗材料9311的抗性水平由中等排驱性和抗生性控制,V20A的抗性主要表现为排驱性,明恢63和扬粳9538的排驱性和抗生性均较弱,暗示其抗性机制主要是耐害性。上述具有强抗生性或排驱性的材料是理想的抗灰飞虱资源。     

Evaluation of Rice Germplasm for Resistance to the Small Brown Planthopper(Laodelphax striatellus)and Analysis of Resistance Mechanism

One hundred and thirty-eight rice accessions were screened for resistance to the small brown planthopper(SBPH)resistance to SBPH were detected,accounting for 18.1%of the total accessions,which included 2 highly resistant,9 resistant and 14 moderately resistant varieties.Compared with indica rice,japonica rice was more susceptible to SBPH.Antixenosis test,antibiosis test and correlation analysis were performed to elucidate the resistance mechanism.The resistant check Rathu Heenati(RHT),highly resistant varieties Mudgo and Kasalath,and resistant variety IR36 expressed strong antixenosis and antibiosis against SBPH,indicating the close relationship between resistance level and these two resistance mechanisms in the four rice varieties.Antibiosis was the dominant resistance pattern in the resistant varieties Daorenqiao and Yangmaogu due to their high antibiosis but low antixenosis.Dular,ASD7 and Milyang 23 had relatively strong antixenosis and antibiosis,indicating the two resistance mechanisms were significant in these three varieties.The resistant DV85 expressed relatively high level of antixenosis but low antibiosis,whereas Zhaiyeqing 8 and Guiyigu conferred only moderate antibiosis and antixenosis to SBPH,suggesting tolerance in these three varieties.Antibiosis and antixenosis governed the resistance to SBPH in the moderately resistant accession 9311.Antixenosis was the main resistance type in V20A.Tolerance was considered to be an important resistance mechanism in Minghui 63 and Yangjing 9538 due to their poor antibiosis and antixenosis resistance.The above accessions with strong antibiosis or antixenosis were the ideal materials for the resistance breeding.     

8个水稻品种的条纹叶枯病抗性特征

利用强迫饲毒、集团接种、非嗜性测验、抗生性测验的方法研究与分析了8个抗条纹叶枯病水稻品种对条纹病毒和介体灰飞虱的抗性,发现不同水稻抗性品种的抗性特征并不完全相同。IR36、Kasalath、窄叶青8号、道人桥、DV85既抗条纹病毒又抗介体灰飞虱,对条纹叶枯病所表现的抗性是条纹病毒和介体灰飞虱抗性共同作用的结果; 爱知97和Kenta Nakan抗条纹病毒,但不抗介体灰飞虱,对条纹叶枯病所表现的抗性是品种对条纹病毒的抗性;而IR24对条纹病毒和介体灰飞虱仅表现中等抗性。     

光照因素对水稻品种苗期褐稻虱抗性的影响

 在人工气候箱及温室自然条件下研究了光照对品种抗性、植株生势及耐害性和褐稻虱生存、发育的影响。光照不足造成品种苗期抗性减弱甚至丧失，其原因是由于植株的生势减弱导致受飞虱为害后的补偿能力下降。中抗品种耐害性丧失和抗级品种的拒虫性减弱。在短光照生长条件下和长光照条件下，飞虱取食高抗品种的植株，其吸食量若虫生存率和发育进度，均无显著差异，表明高抗品种的抗生性在短光照条件下仍能保持。短光照条件下．如果接虫前或后予以充足的光照条件，或将接虫秧龄提高到4片叶，品种的抗性水平则可保持。     

大豆对食叶性害虫抗性机制的研究

１９９３～１９９６年,利用田间自然虫源,以叶面积损失率为指标,进一步鉴定了从６７２４份大豆资源中筛选出的４６份抗感材料对食叶性害虫的抗性表现。从中选出３份抗虫和３份感虫的材料,用以研究自然虫源下豆卷叶螟、斜纹夜蛾、大造桥虫和筛豆龟蝽的产卵选择性,并在实验室和网室人工接虫条件下,研究了抗感材料对斜纹夜蛾的抗虫性机制。结果表明,田间自然虫源下抗感材料以叶面积损失率为指标的综合抗性相差显著;４种重要食叶性害虫在抗虫品种上的产卵量较少;用抗虫品种叶片饲养斜纹夜蛾幼虫,表现为食量减少、体重变小、死亡率增加、历期延长以及蛹重减轻等,而对蛹死亡率和蛹历期的影响不明显。大豆对食叶性害虫具有明显的排趋性和抗生性,尤以后者为重要。     

北方产区花生品种黑斑病抗性鉴定

为筛选花生黑斑病抗源材料，以50个花生品种为材料，在山东省莱西市田间开展黑斑病抗性调查，并在温室条件下对其中7份材料进一步开展抗性鉴定。结果表明，不同花生品种在田间对黑斑病抗性存在差异，共获得4份中等抗病材料；在温室接种条件下，3份材料鉴定为中等抗病。综合田间自然发病和温室人工接种鉴定结果，获得冀农G94、豫花47号和晋花10号3份中抗黑斑病的材料。     

大豆种质资源对SMV3号株系的抗性鉴定

本研究对３４８份大豆种质资源,包括“七五”、“八五”鉴定出的抗源,各地推广品种及国外引进品种,人工汁液摩擦法接种ＳＭＶ３号株系进行抗性鉴定。鉴定结果表明,１１３份资源表现为高抗ＳＭＶ３,占３２．４７％,１１３份表现为中抗,占３２．４７％,１２２份感病,占３５．０６％。抗源主要来自于东北春作大豆区和黄淮海夏作大豆区,本实验南方大豆产区资源抗性较弱。高抗资源主要来源于辽宁、山东、山西、北京以及美国和韩国。不同品种接种后的症状类型不同,表明症状反应是品种与株系互作的结果。国外引进资源接种后顶枯症状较多,表明症状反应和品种的地理来源有一定关系。本文还分析了美国一些抗源对ＳＭＶ３的抗性反应及抗性基因的关系。     

国家长江中下游稻区品种区域试验籼稻稻瘟病抗性分析

【目的】旨在比较国家长江中下游稻区品种区域试验中籼稻稻瘟病抗性在六个省抗性鉴定点的表现及差异。【方法】试验材料为2013-2017年国家长江中下游稻区水稻品种区域试验的800个籼稻参试品种(其中早籼111个、中籼468个、晚籼221个),在浙江、湖南、湖北、安徽、福建和江西共六个鉴定点进行稻瘟病(苗叶瘟和穗瘟)的抗性鉴定。【结果】800个籼稻品种中有47.5%表现为中感稻瘟病,其次为中抗、感和高感,表现为抗的品种所占比例只有0.2%,没有表现为高抗的品种。早籼、中籼和晚籼稻瘟病综合指数六点平均值分别为4.95、4.85和4.54,均属于中感水平。在六个抗性鉴定点中,浙江点综合指数最低,湖北点苗叶瘟最重、穗瘟损失率最低,安徽点苗叶瘟最轻,福建点穗瘟发病率最低,江西点穗瘟发病率、穗瘟损失率和综合指数均为最高。根据稻瘟病抗性综合指数分析,浙江、湖南、湖北、安徽和江西五个鉴定点均表现为中感的品种所占比例最大;福建点表现为中抗的品种所占比例最大。根据穗瘟损失率病级分析,浙江、湖南和湖北点均表现为中抗的品种所占比例最大;安徽点表现为中感的品种所占比例最大;福建点表现为抗的品种所占比例最大,且抗和高感的品种所占比例均为六点中最高,表现为感的品种所占比例为六点中最低;江西点各抗性类型品种的所占比例差异不大。【结论】国家长江中下游稻区水稻品种区域试验籼稻参试品种的稻瘟病整体抗性水平一般。相同的一套品种在不同的鉴定点表现有所不同,用各点的平均值评价参试品种的抗性可以充分、客观地反应参试品种对稻瘟病的抗性水平。     

基于三种抗性机制评价大豆对抗斜纹夜蛾的抗性

通过室内养虫鉴定,农艺性状考查和收获后单株考种,对194份栽培大豆进行了抗斜纹夜蛾的鉴定和评价.结果表明:在抗生性和抗选性上对斜纹夜蛾表现为高抗或抗的材料分别有77份和107份.194份品种在株高、主茎分枝数、单株粒数和单株粒重性状上表现出不同程度的耐害和补偿能力.大豆对斜纹夜蛾的抗生性与抗选性的相关性表现相对一致,而...     

Resistance to the legume pod borer, Maruca vitrata Fabricius, and the probable modalities involved in wild Vigna

A large number of accessions belonging to selected wild Vigna species namely V. unguiculata subspecies dekindtiana, V. oblongifolia, and V. vexillata were evaluated using choice (DCAT) and no-choice (NCFT) laboratory feeding bioassays to determine their resistance to the pod borer, Maruca vitrata Fabricius. The most resistant accessions belonged to V. vexillata, followed by those from V. oblongifolia, with a few outstanding exceptions from V. unguiculata. Even though the latter were the least resistant, they provided the greatest variability among the tested accessions. In the DCAT, the cultivated cowpea line, IT84S-2246, which was used as the susceptible control was always preferred for feeding by the larvae (feeding index [FI] of 1.10–2.60) than the V. unguiculata accessions (FI ranged from 0–0.52). Against the resistant control (itself belonging to V. vexillata), only a few accessions were less preferred, most of these being either V. vexillata or V. oblongifolia. Larvae lost weight on the most resistant from all three species, because they either did not feed, or fed very little. Weight gain was positively correlated with seed damage (r = 0.82, P < 0.01) and the amount of frass produced (r = 0.91, P < 0.01). Seed damage was also positively correlated with the amount of frass produced (r = 0.64, P < 0.05). On the basis of these results, we believe that both antibiosis (post-ingestive effects) and antixenosis (deterrence to boring into the pods to feed) modalities of resistance are involved. The results are discussed further in relation to the origin, domestication and use of these accessions in cowpea improvement.