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。     

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.     

不同品系昆虫病原线虫对蜂巢小甲虫的致病力研究

为明确市售昆虫病原线虫制剂对蜂巢小甲虫（Aethina tumida）幼虫和蛹的致病力,为该害虫的防治提供新的技术措施,室内采用浸渍法、土壤法测定了5种不同品系昆虫病原线虫对蜂巢小甲虫末龄老熟幼虫和蛹的致病力,采用土壤法测定了小卷蛾斯氏线虫（Steinernema carpocapsae All）不同施用时间、不同施用剂量对蜂巢小甲虫幼虫致病力的影响。浸渍法生物测定结果表明,5种不同品系昆虫病原线虫对蜂巢小甲虫幼虫的致病力差异很大,其中小卷蛾斯氏线虫All侵染4 d、12 d后,蜂巢小甲虫幼虫的校正死亡率分别为67.50%±0.05%和72.36%±3.14%,均显著高于其他品系。土壤法生物测定结果表明,昆虫病原线虫对蜂巢小甲虫幼虫具有明显的致死作用,其中小卷蛾斯氏线虫All对蜂巢小甲虫幼虫的侵染效果达100%,显著高于其他线虫品系。蜂巢小甲虫幼虫入土后,按不同时间顺序施用小卷蛾斯氏线虫All,结果表明14 d前施用均能取得良好的防治效果。侵染期线虫小卷蛾斯氏线虫All与蜂巢小甲虫幼虫数量之比大于213∶1时,防治效果最佳。因此小卷蛾斯氏线虫All具有防治蜂巢小甲虫的潜力,可在发生蜂巢小甲虫危害的蜂场推荐使用。     

PEG胁迫下85份引进柱花草种子的萌发特性

为探究不同柱花草的抗旱性强弱,构建柱花草资源抗旱评价体系,以85份引进柱花草为试验材料,分别测定0（CK）、10%和20%质量浓度的PEG-6000渗透液胁迫下萌发期的相对发芽势、相对发芽率、相对胚根长、相对胚轴长、萌发抗旱指数共5项指标,分析不同干旱胁迫对柱花草种子萌发的影响,并结合隶属函数法综合评价柱花草抗旱性能。结果表明：低浓度的PEG对柱花草种子的萌发有一定促进作用,高浓度PEG降低了柱花草种子的相对发芽势和相对发芽率,阻碍了胚芽和胚根的生长,种间表现出较大差异。其中抗旱型材料为头状柱花草CIAT 2250、大头柱花草CIAT 2113和CIAT 1942、蔓性柱花草CIAT 10182,不耐旱材料有墨西哥柱花草CIAT 1590、卡尔奇柱花草CIAT 1616和CIAT 1624。本研究结果为引进柱花草资源抗旱性评价、抗旱品种选育及其机理研究提供了理论依据。     

温度对海岛小花蝽5龄若虫捕食茶黄蓟马功能反应的影响

海岛小花蝽（Orius maxidentex Ghauri）是蓟马的重要天敌昆虫,在热带地区,海岛小花蝽是优势天敌,对高温有较强的适应能力,较适合热带地区的害虫防治。目前海岛小花蝽对茶黄蓟马（Scirtothrips dorsalis Hood）的控害情况尚未明确,为了解海岛小花蝽对茶黄蓟马的控制作用,明确不同温度对海岛小花蝽捕食茶黄蓟马功能反应的影响。本研究以海岛小花蝽5龄若虫为例,在16、20、24、28、32℃温度条件下,测定海岛小花蝽5龄若虫对茶黄蓟马2龄若虫和成虫的捕食功能反应。在16~32℃,随着温度的升高,海岛小花蝽5龄若虫随猎物密度的增加,其捕食量有明显的逐级上升趋势;试验温度范围内海岛小花蝽5龄若虫对茶黄蓟马的捕食功能反应均符合Holling Ⅱ型方程。海岛小花蝽5龄若虫对茶黄蓟马2龄若虫的捕食能力与茶黄蓟马成虫的捕食能力并无明显差异,在28~32℃范围内,海岛小花蝽对茶黄蓟马的捕食量显著高于其他试验温度;海岛小花蝽5龄若虫在试验温度32℃,猎物密度为60头时捕食量最大,对茶黄蓟马2龄若虫与成虫的捕食量分别为34.6、34.0头。海岛小花蝽5龄若虫对茶黄蓟马2龄若虫与成虫在32℃时的处理时间最短,分别为0.0119、0.0115 d。海岛小花蝽5龄若虫对茶黄蓟马的捕食量与茶黄蓟马猎物密度呈正相关,但寻找效应与猎物密度呈负相关,在相同的猎物密度下,随着温度的升高,寻找效应逐渐下降,海岛小花蝽5龄若虫对茶黄蓟马表现出较高的寻找效应。当猎物密度大于最大捕食量时,海岛小花蝽5龄若虫取食具有选择性,仅取食茶黄蓟马腹部。海岛小花蝽5龄若虫在较高的温度条件下表现出对茶黄蓟马有良好的控害能力,是热带地区重要的天敌资源。     

The influence of immigration on population development of Nilaparvata lugens and Sogatella furcifera and its interaction with immigration by predators

Immigration rates and population development of the planthoppers Nilaparvata lugens and Sogatella furcifera were measured in farmers' fields at 12 locations representing four different rice-growing situations in Laguna Province, Philippines. In contrast to findings in temperate climates, immigration rates of the planthoppers alone could not be used successfully to predict population growth and were therefore of little value for forecasting. The lack of such a relationship is probably attributable to the greater importance of within-field factors, particularly natural enemies, in population regulation under the more continuous habitat conditions provided by rice cultivation in the tropics. For the low-land contiguous rice sites significant relationships were shown between immigration rates of two heteropteran predators, Microvelia atrolineata and Cyrtorhinus lividipennis, and population development of both planthoppers when the predators were considered relative to the numbers of prey. In addition a weak negative relationship was demonstrated between S. furcifera population growth and immigration rate of Cyrtorhinus lividipennis for all sites.     

巴氏新小绥螨对芒果茶黄蓟马的功能反应研究

为明确巴氏新小绥螨（Neoseiulus barkeri Hughes）本研究对芒果上茶黄蓟马（Scirtothrips dorsalis Hood）的控害潜能,在室内温度(27±1)℃、RH (75±5)%的条件下,研究了不同虫态巴氏新小绥螨对茶黄蓟马的捕食效能,并通过其瞬时攻击率（a）、处理时间（T_h）和捕食效能（a/T_h）等参数进行综合评价。结果表明:巴氏新小绥螨对茶黄蓟马的成虫、1龄和2龄若虫均可取食,并具有一定的捕食能力。随着猎物密度的增加,捕食螨日取食量逐渐增加,其中巴氏新小绥螨雌成螨和第2若螨对茶黄蓟马1龄若虫的捕食效能最大,每日分别达10.35、12.82头,而雄成螨对茶黄蓟马2龄若虫的捕食效能最大,为每日12.48头。巴氏新小绥螨的雌成螨和雄成螨均对茶黄蓟马的2龄若虫表现出最强的瞬时攻击率,分别为1.0227和1.1208,第2若螨则对茶黄蓟马的雌成虫表现出最大攻击率,为1.5774。     

甘蔗野生种割手密杂交F1代SSR鉴定和遗传分析

割手密具有宿根性好、抗逆性强和适应性广等特性,是甘蔗育种中利用最多,育种成效最显著的野生种。进一步发掘和利用割手密优良抗逆基因资源对现代甘蔗品种改良具有重要意义。为获得更多优良割手密的真实杂交后代,本研究以2个地方种为母本、3个野生割手密为父本进行杂交,获得3个F₁群体,共359份杂交后代。并从21对SSR标记中筛选出在双亲中具有多态性且扩增条带清晰的6对SSR标记,基于高通量的荧光毛细管电泳检测平台进行杂交后代真实性鉴定、亲本指纹图谱分析、遗传相似性分析和特异性条带的遗传分析。结果表明：共筛选出的6对SSR标记对5个亲本材料的分辨率较高,扩增多态性好,每个亲本都具有其特异的SSR指纹,可有效鉴定其杂交后代血缘的真实性;其中,359份F₁个体中共鉴定出真杂种262份,3个组合的真杂种率分别为67.77%、75.51%、75.66%,平均值为72.98%。遗传相似性分析表明2个地方种的遗传相似性系数为0.70,3个割手密两两间的遗传相似性系数分别为0.53、0.60和0.70,地方种和割手密间为0.38~0.53,种间遗传相似性系数小于种内。亲本特异性SSR位点的遗传分析结果表明,3个组合的母本特异性条带遗传率分别为68.47%、80.96%、73.39%,平均值为74.27%,而父本特异性条带遗传率分别为58.90%、76.60%、61.45%,平均值为65.65%,杂交后代具有偏母本遗传倾向,因此,在甘蔗杂交育种中应选择综合农艺性状较好的材料作为母本。本研究结果为今后割手密杂交后代的鉴定提供了高效、可靠的SSR标记选择,同时鉴定出的真实割手密后代群体可为开展割手密优异性状的遗传研究提供种质材料,为选育超亲遗传株系提供科学依据。     

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.     

Resistance to insects by cabbage lines developed in New York when grown in South Texas

Brassica oleracea (L.) germplasm, developed at the New York Agricultural Experiment Station (NYAES), Geneva, as advanced cabbage breeding lines with resistance to lepidopterous pests, was grown in south Texas. Resistance, as measured in terms of insects present on plants, of the breeding lines to arthropod pests was compared with that of cultivars commonly grown in south Texas by monitoring populations of insect pests on the various lines and cultivars. Breeding lines developed at NYAES retained their desired characteristics for resistance to naturally occurring populations of Trichoplusia ni (Hübner) and Plutella xylostella (L.) and also were found to be resistant to Brevicoryne brassicae (L.). A red cabbage cultivar, Red Rock, was found to be more susceptible to Pemphigus populitransversus Riley populations than all other lines or cultivars. Murgantia histrionica (Hahn) was present during one growing season and some NYAES lines that were infested with low numbers of lepidopterous larvae and aphids became heavily infested with this species. Spodoptera exigua (Hübner) populations did not occur in great enough abundance to evaluate differences in resistance among lines and cultivars in 1984 or 1985.     

An on-farm insecticide resistance test kit for colorado potato beetle (Coleoptera: chrysomelidae)

Test kits were developed to enable growers to assess insecticide resistance in Colorado potato beetle populations. Kits included tests for resistance to: carbofuran (Furadan® 4F), phosmet (Imidan® 50WP), esfenvalerate (Asana® 1.9EC), and a combination of esfenvalerate & piperonyl butoxide (Butacide® 8EC). Tests were petri dishes containing filter paper treated with a discriminating concentration of insecticide (i.e., kills susceptible beetles but not resistant beetles). Discriminating concentrations were determined by testing susceptible and resistant strains of beetle across a range of insecticide concentration. About 200 test kits were distributed during the summer of 1988. Results received indicate: 1) Michigan beetle populations were either susceptible or highly resistant to carbofuran, 2) phosmet resistance was more widespread than previously thought, 3) many populations showed moderate to high levels of resistance to esfenvalerate, and 4) adding piperonyl butoxide reduced resistance to esfenvalerate, in many, but not all populations. Resistance kits help growers determine if insecticide resistance is present in beetle populations (either prior to or after an insecticide application), and also generate data useful to research and extension personnel in documenting the extent and distribution of resistance.     

草地贪夜蛾对不同品种玉米室内危害级别及种群适合度比较

草地贪夜蛾[Spodoptera frugiperda(J.E.Smith)]是2019年由缅甸开始入侵我国的一种迁飞性农业害虫,具有取食范围广、极强的迁飞性、适应性及繁殖能力等特点.选育抗性品种是一项重要的农业防治手段,而评价不同玉米品种的危害级别对后续利用多组学分析筛选出特定的抗性基因,培育抗性品种具有指导作用.本...     

Sclerotinia and Phomopsis — two devastating sunflower pathogens

Cultivated sunflower (Helianthus annuus L.) is prone to many diseases caused by fungi, bacteria, and viruses, of which the most detrimental are those caused by fungi. Two of the most important fungal pathogens are Sclerotinia and Phomopsis. Within the genus Sclerotinia, both S. minor and S. sclerotiorum cause a basal stalk rot and subsequent wilt of sunflower, with S. sclerotiorum more widely distributed around the world. Sclerotinia sclerotiorum also incites a head rot and mid-stem rot of sunflower. Since Sclerotinia spp. have a very wide host range and can persist in soil as dormant sclerotia for up to 10 years, the pathogens have been extremely difficult to control with either generic resistance or fungicides. The most effective control is the use of long rotations, tolerant hybrids, and sclerotium-free seed. Gray stem spot is a relatively new disease of sunflower first observed in the early 1980s in Yugoslavia and now considered the most devastating sunflower disease in eastern Europe. Symptoms include large stem cankers and subsequent wilt. Phomopsis helianthi has been identified as one incitant of gray stem spot, but another Phomopsis species may also be involved, both in Europe and in the United States. Foliar fungicides can control gray stem spot, but the development of resistant hybrids has been much more cost-effective.     

油菜F-box-LRR基因全基因组鉴定与核盘菌诱导应答分析

由核盘菌引起的菌核病是一种重要的真菌性病害,筛选菌核病抗病基因对抗病育种具有重要意义。F-box基因多参与植物抗逆反应,LRR作为抗病基因的重要结构域,在植物抗病防卫中起着重要的作用。本研究通过生物信息学方法在甘蓝型油菜基因组中对F-box-LRR基因进行了全基因组鉴定,基于已发表的中双11组织表达数据以及油菜不同品种中油821（抗病）和Westar（感病）接种核盘菌前后的转录组数据,对可能响应核盘菌诱导的BnF-box-LRR基因进行筛选,并结合荧光定量PCR进行验证。共鉴定到161个BnF-box-LRR基因,从系统进化树上可分为4个亚类（FBXLRR1,FBXLRR2,FBXLRR3和FBXLRR4）,其中第四亚类FBXLRR4在蛋白保守序列分布以及基因结构方面,与其它三个亚类具有较大差异,且与拟南芥参与植物抗逆的同源基因聚为一类,因此推测该分支可能主要参与植物胁迫响应。表达分析表明FBXLRR4家族基因在根和叶中有较高的表达水平,且在核盘菌诱导后具有明显的表达变化,暗示这些基因可能参与油菜菌核病抗性功能。     

Effects of cultivar resistance and single fungicide application on rice sheath blight, yield, and quality

The increased number of sheath blight (Rhizoctonia solani)-resistant rice (Oryza sativa) cultivars available will allow producers to use less fungicide and avoid significant reductions in grain and milling yields. Among cultivars currently in cultivation in the southern United States, sheath blight resistance levels range from very susceptible to moderately resistant. A study was conducted to determine the response of cultivars, with different levels of susceptibility, to sheath blight inoculations and fungicide application and to determine the impact of sheath blight disease development on rice yield and quality. Sheath blight epidemics in field plots were initiated by inoculation at the panicle differentiation growth stage in 2006 and 2007. Azoxystrobin at 0.17 kg a.i. ha⁻¹ was applied at mid-boot. Inoculation significantly increased sheath blight severity and incidence and caused yield losses of 8% in moderately resistant cv. Jupiter to 40% in very susceptible cv. Trenasse. Milling yields were affected to a lesser extent. Fungicide treatments reduced sheath blight incidence and severity, regardless of cultivar except in Jupiter. Single azoxystrobin applications were effective in minimizing yield loss due to sheath blight in all cultivars.     

硅对甘蔗黑穗病菌的体外抑菌效果研究

由鞭黑粉菌（Sporisorium scitamineum）引起的黑穗病是甘蔗（Saccharum spp.）生产上最重要的真菌病害。硅是植物生长过程中的有益矿质元素,能够提高植物对生物和非生物胁迫的抗性。目前,关于外源硅对甘蔗黑穗病菌的体外抑菌作用尚未见报道。本研究以硅酸钠（sodium silicate, Na₂SiO₃）和硅酸钾（potassium silicate, K₂SiO₃）处理甘蔗黑穗病菌,观察黑穗病菌的孢子萌发、菌落直径和菌丝生长情况,评价不同硅剂和pH对甘蔗黑穗病菌的体外抑菌效果。结果显示,0.5~20.0 mmol/L Na₂SiO₃和K₂SiO₃均完全抑制甘蔗黑穗病菌的孢子萌发,但1.0 mmol/L Na₂SiO₃促进甘蔗黑穗病菌菌落和菌丝的生长,10.0、20.0 mmol/L Na₂SiO₃和K₂SiO₃则显著抑制菌落和菌丝的生长,表明Na₂SiO₃和K₂SiO₃均会影响甘蔗黑穗病菌的生长,高浓度Na₂SiO₃和K₂SiO₃的抑菌效果明显。在不同pH条件下,低pH（5.87~10.86）处理下的甘蔗黑穗病菌孢子有萌发,但其萌发率随着pH的增大逐渐降低,高pH（≥10.96）完全抑制孢子萌发,此外,pH为9.40和11.57对菌落直径的抑制效果明显。调整pH为6.0的低浓度Na₂SiO₃（0~5.0 mmol/L）和K₂SiO₃（0~3.5 mmol/L）对孢子萌发影响小,但pH为6.0的高浓度Na₂SiO₃（7.0~20.0 mmol/L）和K₂SiO₃（5.0~20.0 mmol/L）显著抑制孢子萌发,表明相同pH水平下的K₂SiO₃比Na₂SiO₃及其对应pH处理对甘蔗黑穗病菌孢子萌发的抑制作用更为明显。研究结果为外源硅在甘蔗抗黑穗病的药效试验和防治机理研究提供参考。     

New sources of resistance to Phytophthora megakarya identified in wild cocoa tree populations of French Guiana

Cocoa black pod rot, a disease caused by oomycetes of the genus Phytophthora, causes substantial yield losses throughout the world, particularly in Africa with the very aggressive species Phytophthora megakarya. In order to reduce the impact of that pathogen, priority is given to genetic control through more resistant cultivars, and breeders are seeking sources of resistance in wild cocoa trees. Wild cocoa trees were surveyed in French Guiana between 1985 and 1995, leading to the collection of abundant plant material from more than 200 mother trees originating from five river basins. We present here the results of tests to assess resistance to the species P. megakarya (a species only existing in Africa), conducted at CIRAD in Montpellier, France, on circa 40 genotypes collected in the Camopi river basin, along with approximately 20 genotypes from other populations (Kérindioutou, Borne 7, Euleupousing, Pina and Oyapok). The strain used for artificial inoculation was NS269, isolated in Cameroon. Seven cacao clones were classified as “highly resistant” and 29 as “resistant”, some of which displayed greater resistance to P. megakarya than the reference resistant clone IMC 47. This study suggests that the wild material from French Guiana could play a significant role in controlling P. megakarya in Africa and also Phytophthora palmivora in all cocoa-producing zones.     

Fine screeningSolanum (potato) germplasm accessions for resistance to Colorado potato beetle

This study was conducted to investigate the utility of systematic screening at the genotype level withinSolanum accessions highly resistant to the Colorado potato beetle. Evaluations of clonally replicated genotypes showed that most accessions reported to be uniform when screened as populations contained small but significant variation among genotypes for resistance to oviposition, larvae, and defoliation, differences for numbers of larvae being most common. Adult counts and percentage defoliation were not as useful in evaluating among-genotype variability in beetle resistance. Genotypes ofS. pinnatisectum WRF 343 andS. tarijense PI 473227 were the most uniformly and highly resistant to Colorado potato beetle. Genotypes of S.berthaultii PI 473331,S. chacoense PI 473405, andS. tarijense PI 473336 were moderately to highly resistant, and genotypes ofS. bukasovii PI 473494 andS. canasense PI 230511 were uniformly susceptible to Colorado potato beetle. Nonparametric correlation analyses indicated that number of egg masses, small larvae, large larvae, and defoliation scores were positively correlated, negatively correlated, or not correlated, depending on the species. One generation of selection attempting to segregate resistance and susceptibility in nearly uniform and highly resistantS. pinnatisectum WRF 343 resulted in “divergent” populations that could not be distinguished from each other or the base population. Thus, through genotype (“fine”) screening and selection, we showed that some existing populations are virtually pure for extreme resistance. Use of individuals from such families would make screening breeding populations more efficient, and reduce the risk of losing resistance genes that have non-dominant effects. Fine screening, recurrent selection, and maintenance of such elite populations is recommended as an extension of population-based evaluation usually done by genebanks.     

Inheritance of resistance to sclerotinia stem rot (Sclerotinia trifoliorum) in faba beans (Vicia faba L.)

Stem rot, a fungal disease caused by Sclerotinia trifoliorum Eriks., is often a serious problem in many important forage legumes including faba beans (Vicia faba L.). Understanding the inheritance of resistance to the disease is essential for effective breeding of resistant cultivars. Experiments were conducted to study the inheritance of resistance to stem rot of faba beans. The F₁, F₂, and the backcross generations of five crosses between four resistant and four susceptible populations (Alto × Polycarpe, A-90 × Polycarpe, ILB-1814 × A-247, A-90 × A-244, VT × Tanagra) were used. The eight populations were crossed properly in the field, and progenies of F₁ and F₂, as well as backcross progenies of F₁ with each of their parents, were evaluated for resistance to stem rot disease under controlled conditions after artificial inoculation of the plants with carrot root pieces colonized by the fungus. On the assumption that inheritance of stem rot resistance is governed by a single dominant gene, no significant differences were found between the observed and the expected frequencies of resistance for progenies, except for one cross. As the expression of resistance to the disease fits the expected ratios for a single dominant gene model, it is concluded that the inheritance of resistance to sclerotinia stem rot in the evaluated faba bean populations is controlled by a single dominant gene.     

西瓜品种‘黑皮’对瓜蚜的抗性遗传分析

采用单株蚜量比值法室内鉴定与RAPD、SCAR标记相结合的方法,系统开展了西瓜品种‘黑皮’对瓜蚜的抗性遗传分析。结果表明,以‘黑皮’和‘花绿’为亲本的杂交F₁代对瓜蚜表现为抗性,自交F₂代植株表型出现抗感性分离,抗蚜与感蚜植株分离比经χ²测验符合3∶1分离规律,并用筛选获得的RAPD标记WO4₆₀₀和SCAR标记WO4-S₅₃₀验证了4个抗蚜品种、4个感蚜品种和10个F₂抗蚜单株、10个F₂感蚜植株。结果以‘黑皮’为亲本的西瓜抗蚜性由单显性核基因控制且能稳定遗传,‘黑皮’‘绿美人’‘黑美人’和‘惠兰’品种对瓜蚜具有良好抗性,‘花绿’‘凤光’‘蕙宝’和‘甜美人’品种则易感蚜虫。