Impact of varietal resistance in rice and predation on the mortality of Sogatella furcifera (Horváth) (Homoptera: Delphacidae)

Highly resistant, resistant and susceptible rice cultivars were tested in the greenhouse to determine their effect on Sogatella furcifera (Horváth) populations. The highly resistant cultivar IR2035-117-3, with resistance genes Wbph 1 and Wbph 2, caused the highest S. furcifera mortality. When the effects of varietal resistance and predation were combined the increase in mortality due to predators was additive. The spider Lycosa pseudoannulata Boes. et Str., mirid bug Cytorhinus lividipennis Reuter, ladybird beetle Harmonia octomaculata (F.) and rove beetle Paederus fuscipes Curt. were effective predators of S. furcifera and generally caused 30% mortality on the various cultivars. Results indicate that the integration of varietal resistance and predation would provide effective control of S. furcifera populations under field conditions.     

模拟高温季节稻丛基部小气候条件下白背飞虱的生长发育与繁殖

白背飞虱[Sogatella furcifera (Horváth)]是我国最重要的水稻害虫之一。每年6—8月高温是制约该虫在长江流域发生的重要生态因子。白背飞虱多栖息于稻丛基部,其小气候特征常不同于大气。采用变温变湿、恒温恒湿两种方式,通过分别模拟高温期间(日最高温35℃~39℃)水稻拔节后稻丛基部和大气温湿度条件,研究了高温季节稻丛基部与大气温湿度条件对白背飞虱的生长、发育和繁殖的影响。结果表明,稻丛基部温湿度条件下,白背飞虱的生长、发育和繁殖在变温变湿模拟与恒温恒湿模拟间无显著差异,白背飞虱能正常地完成生长发育和繁殖。与之相比,模拟大气条件下,白背飞虱生长、发育和繁殖相关的多数指标均受到显著抑制,其中较为重要的单雌产卵量,大气变温变湿模拟较稻丛基部变温变湿模拟减少了62.1%。可以认为,夏秋高温期间水稻拔节后稻丛基部田间小气候有利于白背飞虱“躲避”高温天气的不利影响。     

不同氮肥水平下转Bt基因水稻对褐飞虱和白背飞虱生态适应性的继代影响

在目前氮肥施用量依然偏多的大背景下,氮肥与转 Bt 基因水稻的相互作用是否会对稻田中非靶标节肢动物产生影响是转基因水稻安全评价的重要内容。本研究在室内条件下用0 kg/hm²、100 kg/hm²和250 kg/hm²3个氮肥水平处理的转 Bt 基因水稻T1C-19和T2A-1以及非转基因亲本水稻明恢63,连续饲养褐飞虱和白背飞虱4代,研究在不同氮肥条件下,转 Bt 基因水稻对褐飞虱和白背飞虱生态适应性的继代影响。结果显示,在同一水稻品种上,氮肥的过量施用,显著提高了褐飞虱和白背飞虱的生态适应性,并且随着代数的增加具有一定的累加效果。同一氮肥水平条件下,转 Bt 基因水稻和对照相比对同代褐飞虱和白背飞虱的若虫发育历期、雌虫体质量、成虫寿命、褐飞虱若虫孵化率、存活率均无显著影响。而在100 kg/hm²和250 kg/hm²施氮水平下取食转基因水稻T1C-19的褐飞虱在第1代至第3代的每雌产卵量均显著低于另一转基因品种T2A-1以及对照品种明恢63,但第4代褐飞虱在各品种上的产卵量无显著差异。本研究结果表明,氮肥的施用显著提高了褐飞虱和白背飞虱的生态适应性,供试两种转Bt基因水稻对褐飞虱和白背飞虱的生态适应性无显著影响。这为转基因水稻的安全评价提供了一定的理论依据。     

Effect of host plant resistance and insecticide on brown planthopper Nilaparvata lugens (Stål) and predator population development in the Mekong Delta, Vietnam

Crop yield and populations of brown planthopper Nilaparvata lugens (Stål), whitebacked planthopper Sogatella furcifera (Horvath) (Homoptera: Delphacidae), green leafhopper Nephotettix spp. (Homoptera: Cicadellidae), and hemipteran and spider predators were monitored on rice varieties susceptible, moderately resistant, and highly resistant to N. lugens, under insecticide-treated and insecticide-free conditions. Nilaparvata lugens outbreaks and hopperburned plants were observed only in plots of the insecticide-treated susceptible varieties. In insecticide-free plots, the yield of the susceptible variety was lower than those of resistant varieties in only one of four seasons. In plots of a moderately resistant and a highly resistant variety, populations of N. lugens, S. furcifera, Nephotettix spp., and predators were generally similar, and yields did not differ, under both insecticide-treated and insecticide-free conditions. In insecticide-free plots, predator-N. lugens ratios were generally higher on resistant varieties than susceptible varieties. Two conclusions can'be drawn from our results relevant to the question of what levels of N. lugens host plant resistance are appropriate for farmers who do not overuse insecticides. First, susceptible varieties will not necessarily be damaged by N. lugens, even when N. lugens outbreaks occur in adjacent plots. Second, moderate and high levels of N. lugens resistance do not appear to be incompatible with biological control of N. lugens or other homopteran pests.     

Biodiversity and Dynamics of Planthoppers and Their Natural Enemies in Rice Fields with Different Nitrogen Regimes

Biodiversity both theoretically and practically has relevance in addressing many problems of contemporary agriculture and allows the formation of functional groups that drive key ecosystem processes [1]. One of the most important processes in agroecosystems is pest regulation, because biodiversity is related closely to host-plant resistance, pest management attributes, natural biological control agents and their impacts, and stability as the ecological basis for pest management [2-3]. On one h…     

水稻抗性蛋白OsRRK1抗褐飞虱机理分析

目的 OsRRK1（Rop-interacting receptor-like kinase 1）蛋白是水稻中第一个被研究的类胞质受体激酶RLCKⅥ家族蛋白。在调控水稻叶片的卷曲和对褐飞虱的防御中都起着重要作用,但是其调控机理尚不清楚。本研究试图进一步探究OsRRK1基因抗褐飞虱的机理。方法 利用酵母双杂交的方法分析OsRRK1蛋白与OsLecRK（lectin-like receptor kinase）、OsLecRK1、OsLecRK2、OsLecRK3的互作关系,OsLecRK是抗褐飞虱基因BPH15区间的候选基因,是水稻先天免疫系统中一个重要成员,既参与水稻先天免疫反应,包括对褐飞虱、白叶枯病和稻瘟病的抗性,又参与水稻的发育过程。OsLecRK1、OsLecRK2、OsLecRK3的基因簇组成抗褐飞虱基因BPH3,含BPH3基因的水稻具有广谱、持久的抗虫性。同时利用DNAMAN软件分析OsLecRK蛋白与OsLecRK1、OsLecRK2、OsLecRK3的同源性。结果 DNAMAN的分析结果显示OsLecRK与OsLecRK1、OsLecRK2、OsLecRK3的同源性都很高,蛋白一致性在50%以上;酵母双杂交结果显示OsRRK1与OsLecRK、OsLecRK2和OsLecRK3互作。结论 OsRRK1通过与抗褐飞虱基因BPH15和BPH3候选基因的相互作用参与水稻抗褐飞虱过程。     

Resistance of wild rices, Oryza spp., to the brown planthopper, Nilaparvata lugens (Stål) (Homoptera: Delphacidae)

Of the 128 wild rices screened, 83 accessions were resistant to the brown planthopper Nilaparvata lugens (Stål). Resistant accessions were non-preferred and significantly more individuals settled on susceptible TN1 plants than on resistant ones. The quantity of food ingested and assimilated by N. lugens on resistant accessions was less than on susceptible TN1. N. lugens caged on resistant accessions had slow nymphal development, reduced longevity and low fecundity. Two wild rice species, Oryza officinalis and O. punctata, reduced the percentage hatchability of N. lugens eggs. A significant reduction in population growth was observed on resistant accessions compared with susceptible TN1.     

Assessment of allelopathic potential of barnyard grass (Echinochloa crus-galli) on rice (Oryza sativa L.) cultivars

Laboratory, greenhouse and field studies were conducted to assess the allelopathic potential of 44 rice cultivars (Oryza sativa L.) on barnyard grass (Echinochloa crus-galli P. Beauv. var. oryzicola Ohwi). Rice cultivars exhibited marked differences in the inhibition of barnyard grass growth and development. In the laboratory, Gin shun rice cultivar extracts exhibited the greatest activity on the weed seedling growth, reducing dry weight by 61%, while Kasarwala mundara cultivar extracts exhibited the greatest activity on seed germination, reducing germination by 23% and germination speed by 46%. In a greenhouse study of a residue mixture, the Philippine 2 cultivar showed the greatest inhibition percentage on seedling emergence (57%), total seedling length (74%) and dry weight (73%). In the field study, the Juma 10 cultivar demonstrated the most inhibitory effect by reducing barnyard grass tiller number (80%), leaf area (49%) and leaf (61%) and stem (74%) dry weight (68%). These results suggest that there are differences among the varieties for allelopathic inhibition of barnyard grass, and that the development of barnyard grass suppressive rice cultivars that have greater allelopathic potential may be possible.     

Levels of resistance of rice cultivars and the weed Leersia hexandra L. to Nephotettix malayanus Ishihara et Kawase and N. virescens (Distant)

Studies on the mechanisms of resistance of some rice cultivars and the weed, Leersia hexandra, to Nephotettix malayanus indicated low survival and popu;ation growth of the insect on resistant cultivars. Tests on feeding behaviour indicated that more feeding punctures were made on resistant than on susceptible cultivars. The amount of honeydew excreted was not related to the levels of resistance. Honeydew excreted on resistant cultivars was acidic (pH 5·08–6·92) and on susceptible L. hexandra, basic (pH 7·56). On the basis of the quality of honeydew excreted, N. malayanus was considered to be predominantly a xylem feeder. A test on the serial transmission of the rice tungro virus (RTV) showed that N. malayanus transmitted the virus for only one day after feeding acquisition. N. virescens was a more efficient vector of RTV than N. malayanus. N. malayanus prefers to feed on L. hexandra rather than on the rice cultivars tested.     

Clonal performance of perennial Oryza sativa/O. rufipogon selections and their combining ability with O. sativa cultivars for survival, stolon production and yield

In Southeast Asia, upland rice (Oryza sativa) is an annual crop typically grown for subsistence on hilly lands that are at risk for soil erosion. If perennial cultivars of upland rice were developed, they would provide farmers with an inexpensive tool to produce a preferred food while conserving soil. O. rufipogon, the undomesticated progenitor of O. sativa, includes perennial and stoloniferous forms. To evaluate the feasibility of developing perennial cultivars by combining genes of O. sativa and O. rufipogon, four trials were conducted in an upland field at IRRI: O. sativa/O. rufipogon F₁ clone and cutting height trial, F₂ family trial, and two O. sativa/stoloniferous-selection factorial mating design trials. Plants were established at the beginning of the rainy season, then subjected to a 6-month dry season and evaluated for survival after 1 year. Of the 2101 cultivar control plants, only three IR47686-1-4-B individuals survived and none produced stolons. The 18 F₁ clones, which were selected from previous trials with less drought stress, ranged in survival from 4.4 to 91.4%. Cutting height at harvest did not affect survival. Survival among the F₂ families ranged from 9.4 to 31.9%. Segregation for stolon presence did not differ from a 3:1 ratio for five of the six F₂ families, suggesting the effect of a single dominant gene. Average yields per plant for the F₂ families were 1/3 to 1/9 of yields for the cultivars. However, by crossing the F₁s to cultivars, yield potential was almost fully recovered. For the full-sib families of the factorial trials, survival ranged from 0.0 to 48.6%. Azucena and IR47686-1-4-B, both japonica cultivars, exhibited greater general combining ability for survival relative to the six other cultivar parents. Thus, the process of developing perennial cultivars of rice should include screening annual cultivars to identify those with the best combining ability for survival. To develop cultivars of perennial upland rice, drought avoidance and/or tolerance from annual upland cultivars must be combined with the capacity for perennial growth from wild perennial species. The frequency of stolonifereous testcross progeny was lower than expected and was affected by the O. sativa parent. Thus, additional genes likely affected stolon penetrance and expression. Analyses of covariance indicated that stolons improved the likelihood of survival for progenies of the factorial trials but the effect was small (b < 0.1), and that yield (g/plant) had a small negative effect on percent survival (b = −0.13 to −0.32). This study demonstrated that it was possible to introgress genes for perennial growth from wild O. rufipogon accessions into domesticated O. sativa. Additionally, strategies for developing perennial cultivars of upland rice were improved.     

Sampling and development of economic injury levels for Anthonomus rubi Herbst adults

Field studies were conducted in northwestern Turkey from 1998–2000 to examine population dynamics of adult strawberry blossom weevils (Anthonomus rubi Herbst), and to establish economic injury levels based on the relationship between densities of overwintered adults and yield losses. Adult weevils were sampled weekly in untreated and insecticide-treated plots using a sweep net. Sweep net catches showed that the abundance of A. rubi adults had two peaks; the first between late-April and early-May, and the second between late-June and mid-July. Linear regression revealed a strong relationship between overwintered and new-generation adult densities. The overwintered-generation adults had generally higher mean population densities than the new-generation. A significant linear decrease was observed in strawberry yields as densities of overwintered-generation adults increased. Percentage yield losses varied between 1.64% and 13.42% among sites. Estimated economic injury levels ranged from 1.00 to 4.00 adults per sweep depending on the management scenario, control cost, control efficacy, and crop value.     

Physiological Age Status of Female Adults and Off-Season Survival of Rice Leaffolder Cnaphalocrocis medinalis in India

Rice leaffolder, Cnaphalocrocis medinalis, is one of the major foliage feeders found in the rice growing regions in India. When the crop was at maturity, numerous adults of rice leaffolder were found in the rice fields though the larval population gradually decreased, and no eggs were found on rice leaves. The population characteristics of C. medinalis were assessed based on the physiological age status of adults at different crop growth stages. Based on egg development within ovarioles, ovariole appearance, number and colour of fat bodies, and characteristics of bursa copulatrix, physiological age status of the adults was described, which served as a basis for the determination of age composition. C. medinalis adults were found during the first week of August on rice plants, of which 44% were in Age 0 with immature ovaries, indicating immigrants. However, 28% adults each were at Ages 1–2 with developing ovaries, indicating local breeding population. The carryover and off-season survival of C. medinalis were also studied to determine the contribution of the alternative hosts in the population growth that helped in devising efficient management strategies. Rice was the most preferred host followed by Triticum aestivum, Echinochloa crusgulli and Brachiaria plantaginea. Various routes of the carryover of C. medinalis from season to season were discussed.     

稻飞虱饲养与抗药性筛选的方法研究

就几种新鲜稻苗对褐飞虱和白背飞虱生长发育和繁殖的影响进行了比较,发现20~25℃下无土培育的幼苗最适合室内稻飞虱生长、发育和繁殖,适合室内飞虱的大批量饲养。通过不同筛选方法对褐飞虱和白背飞虱进行抗性筛选,比较不同方法的筛选效果,发现稻苗和飞虱同时喷雾的方法操作方便、抗性发展快,最适合于大量飞虱的抗性筛选。     

Agronomic and economic evaluation of Sesbania rostrata green manure establishment in irrigated rice

Research on crop establishment methods may improve green manure performance, reduce costs, and increase the adaptability of pre-rice green manure technology in lowland rice-based cropping systems. A two-season field experiment was conducted at the International Rice Research Institute (IRRI) in Los Baños, Philippines in 1991–1992 to compare four establishment practices of Sesbania rostrata green manure (zero tillage, with tillage, relay cropping in rice for 2 or 4 weeks) with four mineral N fertilizer levels (0, 30, 60, and 90 kg urea N/ha) in an intensive irrigated lowland system with three rice crops per year. S. rostrata was grown twice a year during the 43-day dry-wet and wet-dry transition periods between the wet and dry season rice crops.

Grain yield potential and fertilizer responsiveness of rice was generally highest in the dry season. On the other hand, S. rostrata growth was more vigorous in the wet season (long-day period) than in the dry season, regardless of establishment method. Green manure N accumulation was lowest with zero tillage (30 and 90 kg N/ha in dry and wet season, respectively) and highest when it was relay-cropped for two weeks (60 and 180 kg N/ha in dry and wet season, respectively). Land preparation for Sesbania ensured best green manure stand (> 100 plants/m² vs 20–40 plants/m² at no-till establishments) but increased costs of green manuring by US$16/ha compared with other establishment methods. A quadratic response function between mineral fertilizer equivalence and green manure N indicated that up to 75 kg N/ha, lowland rice uses green manure N more efficiently than urea. Depending on season and establishment method, S. rostrata substituted for 35 to 90 kg of split-applied urea N. Benefit-cost ratios indicated that pre-rice green manure use in the wet season under the current fertilizer and labor prices in the Philippines was a less attractive economic option than mineral N fertilizer. This was true for all establishment methods. In the dry season, S. rostrata established by relay cropping gave the highest rate of return. The 2-week relay cropping of green manure with irrigated rice gave highest green manure N accumulation and rice grain yield, and may be economically viable where fertilizer prices are higher or labor costs are lower than in the Philippines.     

水稻苗期耐热种质资源筛选及QTL定位

[目的]鉴定和筛选水稻极端耐热种质或基因,为培育耐高温水稻新品种提供技术支撑.[方法]以耐热等级和幼苗存活率为指标对不同类型水稻苗期耐热性进行鉴定评价,以筛选和鉴定耐热种质资源及主效QTL.[结果]不同类型水稻品种苗期耐热性存在明显差异,籼稻品种耐热性明显强于粳稻品种,籼稻和粳稻品种均存在极端耐热和极端敏感种质资源;共...     

单季晚稻防治稻飞虱药剂筛选试验

6种药剂防治稻飞虱试验结果表明,呋虫胺20%可湿性粉剂30 g/667 m2、烯啶·吡蚜酮60%水分散粒剂12 g/667 m2、烯啶·吡蚜酮80%水分散粒剂10 g/667 m2对单季晚稻稻飞虱均有不错的防治效果,尤其是对低龄若虫。烯啶·吡蚜酮60%水分散粒剂12 g/667 m2、烯啶·吡蚜酮80%水分散粒剂10 g/667 m2对高龄若虫表现最为突出,速效性好,同时对天敌几乎无影响。吡蚜酮50%可湿性粉剂30 g/667 m2速效性较一般,但持效性较好。吡虫啉10%可湿性粉剂50 g/667 m2的防效较差,对高龄若虫几乎不起作用。毒死蜱40%水乳剂100 mL/667 m2加氟啶虫胺腈22%悬浮剂14 mL/667 m2速效性一般,持效性较差,却对天敌影响较大。以六（4）代褐飞虱为主的稻田为例,需掌握低龄若虫或卵孵高峰期,科学选用吡蚜酮50%可湿性粉剂、呋虫胺20%可湿性粉剂、烯啶·吡蚜酮60%水分散粒剂、烯啶·吡蚜酮80%水分散粒剂进行轮换防治。     

三亚南繁区稻田捕食性天敌研究

海南省南繁区位于热带地区。水稻是南繁区种植最多的作物,占南繁区总面积的60%。为了更好地开展南繁区水稻害虫的生物防治和监测,必须弄清南繁区稻田的捕食性天敌种类和优势种情况。本研究采用吸虫器取样法调查研究了三亚南繁区2013年三季水稻生长期间稻田捕食性天敌的群落结构,明确了三亚南繁区捕食性天敌有9目40种,重点研究了优势种稻红瓢虫和锥腹肖蛸的种群发展情况,为热带地区水稻害虫的生物防治和南繁稻田监测指示性昆虫的确定提供科学依据。     

稻鸭共作系统中稻飞虱及主要捕食性天敌类群之间的关系

 以生态位理论为依据,研究了施用化肥（化肥区）、稻鸭共作（稻鸭区）和无化肥农药（对照区）3个处理区中稻飞虱与主要捕食性天敌类群的数量及消长动态、时间生态位特征,并进行了灰色关联度分析。结果表明,3个处理区稻飞虱与主要捕食性天敌类群的数量、时序特征、时间生态位宽度与重叠指数等均存在不同程度的差别。稻鸭共作使稻飞虱发生高峰期的数量、主要捕食性天敌总量降低,与化肥区、对照区相比,益害比分别下降了172%和2614%;与化肥区相比,稻鸭区除瓢虫外,其他捕食性天敌类群的生态位宽度均降低214%~3577%,多数天敌之间如肖蛸与隐翅虫、园蛛与瓢虫等的生态位重叠度增加,但瓢虫、球蛛对稻飞虱的跟随效应和控制潜能加大,一定程度上弥补了天敌数量减少、对稻飞虱影响减弱等不足,使得晚稻整个观测期内稻飞虱的总数比化肥区下降2370%。不同稻作模式、不同类型的捕食性天敌与稻飞虱的关联性不同,稻鸭区中瓢虫、狼蛛和球蛛对稻飞虱影响较大。     

利用CRISPR/Cas9创建osarf7突变体及其农艺性状调查

[目的]探究OsARF7基因在水稻生长发育中的生物学功能及其对水稻农艺性状的影响.[方法]利用CRISPR/Cas9技术,在粳稻中花11背景下对OsARF7进行定向编辑,获得OsARF7基因突变植株,并考查其农艺性状.[结果]获得22株T0代转基因株系,经PCR扩增潮霉素基因鉴定出20株阳性植株.提取T2代转基因植株的...     

Natural enemies of the bagworm, Metisa plana Walker (Lepidoptera: Psychidae) and their impact on host population regulation

The bagworm, Metisa plana (Lepidoptera: Psychidae) is an important pest of oil palm, capable of being present as outbreak, which could cause a crop loss of up to 44%. Circumstantial evidence has long indicated that natural enemies play an important role in the population regulation of this pest. However, direct field data on the enemies themselves has been lacking.

A field study on a population of M. plana was made at PORIM Kluang, Johor, Malaysia from September 1988 to December 1992. The population of bagworm was initially high (late 1988, up to 38 larvae/frond, and in early 1990, up to 30 larvae/frond) but remained extremely low in the subsequent period (< 10 larvae/frond).

The population of M. plana was affected by both primary and secondary parasitoids and predators. Among the primary parasitoids, Dolichogenidea metesae was the most pronounced larval parasitoid of M. plana. This parasitoid was commonly attacked by hyperparasitoids, particularly Pediobius anomalus and Pediobius imbreus. A hypothetical life table constructed from the mortality figures of the declining part of the population during late 1988 confirmed that the natural enemies played a key role in suppressing the bagworm population.

The present study confirmed that overlapping generations were vital for the persistence of parasitoids of M. plana. The paper also suggested a possible need of alternative hosts. An active predator, Callimerus arcufer was also commonly encountered.