玉簪叶斑病菌菌株 Ch10的分离及生物学特性

为了明确尾孢属真菌的生物学特性,采用菌丝生长速率法及液体振荡培养法,对影响玉簪尾孢叶斑病菌菌株 Ch10菌丝生长的条件进行了研究。结果表明,除光照条件外,其他培养条件对 Ch10菌丝生长均有显著影响;Ch10菌丝生长最适温度为25℃,最适 pH 为6,对乳糖、麦芽糖、酵母膏和硝酸钾利用最好,在 MEA 培养基上的生长略快于其他培养基,但培养21 d 最大菌落直径仅2．37 cm,生长非常缓慢,而且极少产孢。     

Inheritance of Cercospora Leaf Spot Resistance in Mung Bean, Vigna radiata (L.) Wilczek

Inheritance of Cercospora leaf spot resistance in mungbean was studied in 20 crosses involving crosses of resistant × susceptible, resistant × resistant, susceptible × susceptible lines. 3:1 ratio was observed in all 14 F₂s involving resistant × susceptible parents. The inheritance of Cercospora leaf spot resistance is thus controlled by a single recessive gene. Our results are contradictory to observations of Thaklk et al. (1977 a, b) who found monogenic dominant inheritance of Cercospora leaf spot resistance in mungbean.     

Field and greenhouse evaluation of the components of partial resistance to early leafspot in peanut

Summary Ten peanut (Arachis hypogaea L.) genotypes were evaluated fro components of partial resistance to Cercospora arachidicola Hori in the field and in two detached leaf tests in the greenhouse. The relationships among the resistance components in the two environments were examined by computing rank correlations among the components measured in the greenhouse and among those measured in the field. A comparison of field and greenhouse testing for partial resistance was made by determining the correlations between components measured in the two testing methods. The genotypes were significantly different for all the components of resistant measured in the field and for most of the components measured in the greenhouse. In the field study necrotic area/10 cm² leaf area was moderately correlated (r=0.58) with lesion number/10 cm² leaf area and highly correlated (r=0.71–0.76) with total lesion number, predicted number of days after planting (X) to reach a standard lesion count, and defoliation. In the greenhouse only the correlation between necrotic area (mm²)/10 cm² leaf area and sporulation/leaf was highly significant (r=0.71–0.83) in both greenhouse tests. Necrotic area (mm²)/10 cm² leaf area measured in the field was significantly correlated with that measured in the greenhouse (r=0.66). Sporulation/leaf measured in the greennhouse was significantly correlated (r=0.66) with lesion increase in the field (measured as predicted X). It should thus be possible to evaluate and select for components of partial resistance in the greenhouse to develop resistant lines for the field.     

Sources of resistance to diseases of sugar beet in related <Emphasis Type="Italic">Beta</Emphasis> germplasm: I. Foliar diseases

Resistance to four foliar diseases of sugar beet (Beta vulgaris ssp. vulgaris), virus yellows caused by Beet mild yellowing virus (BMYV) and Beet yellows virus (BYV), powdery mildew (Erysiphe betae) and Cercospora leaf spot (Cercospora beticola), was assessed in up to 600 accessions of closely related wild and cultivated Beta species. Most accessions were from the Section Beta, a taxon containing types most closely related to, and sexually compatible with, sugar beet and therefore most valuable for use in crop improvement. Between 1–12% of accessions were highly resistant (resistance scores of 2 on an international standardised resistance scale of 1–9) to these diseases. These levels, however, underestimate the potential number of resistant sources available from this section as some accessions with intermediate mean resistance scores contained a significant proportion of highly resistant plants within segregating populations. Variation in resistance to all diseases except BYV was observed within the Section Beta. Much higher levels of resistance were observed, and more frequently, in more distantly related sections of the genus Beta. Accessions of the Section Corollinae were highly resistant to both viruses (>62% of accessions tested), but less so to Cercospora (15%) and they were very susceptible to powdery mildew. Section Procumbentes accessions were highly resistant to BMYV and Cercospora (100%) but less so to powdery mildew (50%) and BYV (20%). However, sexual incompatibility between these sections and sugar beet make utilisation of these sources impractical using conventional breeding methods.     

药剂防治大豆灰斑病的效果与效益研究

在大豆生长的不同时期,采用不同的杀菌剂,对药剂防治大豆灰斑病的效果与效益进行了研究。结果表明药剂防治大豆灰斑病的关键时期是在大豆开花到结荚和鼓粒初期,过迟施药防病效果下降。用YPB=Y(1-YPSi)×(1 YPTj)×(1 YPKl)模型可预测产量总防效;用SPB=Y′(1-SPSi)×(1 SPTj)×(1 SPKl)模型可预测病粒率总防效;用PEB=YPM×(1 YPB)×PWn-YPM×PW′n模型可预测药剂防治总效益。模型经在八五五农场大面积运行,获得很好的经济效益。     

大豆叶片结构与灰斑病抗性的研究Ⅱ.大豆叶片组织结构与灰斑病抗性的关系

对大豆灰斑病抗病品种和感病品种的叶片组织结构，主要包括栅栏组织层数，栅栏组织密度，上下表皮细胞密度，蜡质含量及叶比重等，进行了比较研究。试验结果表明抗病品种叶片的栅栏组织排列整齐，紧党性,而且层数相对较多，可以抵抗病菌的侵入和扩展，成为抗病的一个结构屏障；抗病品种的叶片蜡质含量高于感病品种，表明大豆叶片本身具有的蜡质层是抵抗和延迟病原菌侵入的另一个结构屏障。在叶比重上，抗病品种与感病品种没有明显差异。     

禾本卡克防治甜菜褐斑病的效果

以500倍液的禾本卡克喷施2～3次防治甜菜褐斑病有明显的防治效果。病情指数降低22．6-26．1，甜菜产量提高8．1％-10．6％．含糖率增加0．7～1．1度。     

Variation in progenies of an Arachis hypogaea x diploid wild species hybrid

Summary Derivatives of a cross between cultivated peanuts, Arachis hypogaea L. (2n=40), and the wild species collection GKP 10017 (2n=20) were compared morphologically, for leafspot resistance and for yield. The objective of the study was to determine the effects of wild species germplasm on the A. hypogaea genome. The sterile F₁ hybrid which resulted from crossing the two species was treated with colchicine to restore fertility at the 6x ploidy level. The resulting hexaploid was cytologically unstable and progeny lost chromosomes until stability was regained at the 2n=40 chromosome level. Forty-seven characters were used to analyze the variation among plants in the tetraploid interspecific hybrid population. The plants were compared to four cultivated lines plus GKP 10017. Many hybrids were intermediate to the two parents in morphology. Individual traits such as growth habit, pod and seed size, elongation of the constricted area between pods, nodulation and leaflet size were altered by the presence of GKP 10017 germplasm in many of the hybrid plants. Cercospora arachidicola Hori and Cercosporidium personatum (Berk. & Curt.) Deighton resistances were evaluated for all plants. Several hybrids had few lesions due to either leafspot pathogen. In addition, 24 largeseeded interspecific hybrid selections were compared to the cultivated variety NC 5 for yield. Five selections were superior to both parents at p=0.01. Morphology, disease resistance and yields appeared to be greatly influenced by the wild species GKP 10017 germplasm in plants of the interspecific hybrid population. The potentials of using wild species for improvement of the cultivated peanut are discussed.Paper number 5948 of the journal series of the North Carolina Agricultural Research Service, Raleigh, NC 27650. The investigation was supported in part by ICRISAT and SEA-CR grant no. 701-15-51.     

甜菜褐斑病菌对苯并咪唑类等杀菌剂抗药性的研究

本试验对全国主要甜菜(或种子)产区的C.beticola645个单孢菌株进行了测定,发现来自内蒙古、宁夏、吉林的菌株绝大部分对苯并咪唑类杀菌剂具有高度耐药性,来自淮阴的菌株大部分对苯并咪唑类杀菌剂表现敏感;所有菌株对百菌清与速克灵的反应与野生菌株相似;抗性菌株对托布津、苯菌灵、噻菌灵、多菌灵具有交互抗性;抗性菌株在无药的PSA上连续培养12代后,只表现生长速率有所下降,而抗药性未发生明显变化。     

基于SSR标记关联分析挖掘大豆灰斑病10号生理小种抗病资源

培育灰斑病抗性品种可降低灰斑病对大豆生产的危害。本研究以202份黑龙江省近25年主栽的大豆品种构建关联群体,在人工接种条件下鉴定大豆品种对灰斑病10号生理小种抗病指数。利用187对SSR标记对遗传多样性、群体结构和连锁不平衡位点进行分析,通过GLM 和MLM两种模型对大豆品种的灰斑病抗性与标记进行关联分析,进一步分析抗性关联位点等位变异与抗性表型效应关系。结果表明：202份大豆品种对灰斑病10号生理小种抗性遗传变异系数为14.26%;187个标记在群体中共获得809个等位变异,平均等位变异为4.42个,变幅2~10个,其中17号染色体的平均PIC值最高（0.64）,12号染色体的平均PIC值最低（0.26）;检测到稀有等位变异146个,特有等位变异位点58个;无论共线性组合位点还是非共线性组合位点均存在不同程度LD,连锁不平衡P<0.05支持的对数占总对数的21.65%;202份大豆品种被划分为3个亚群,亚群POP1与POP3之间遗传距离最小（0.03）,亚群POP2与POP3之间遗传距离最大（0.35）;两种模型共同检测到11个SSR标记与灰斑病10号生理小种抗性显著关联,其中位于3号染色体上的Satt549的贡献率最大,可解释表型变异14.74%;具有增效效应的等位变异共有24个,增效效应超过10的等位变异有7个,增效效应最大为Satt703-247（19.62）,典型载体材料为合丰29;其次是Satt587-185（19.58）,典型载体材料为东农50;Satt549位点增效等位变异的平均效应值最高（13.87）,Sat_366位点增效等位变异的平均效应值最低（0.84）。聚合优异等位变异和载体材料可为培育抗灰斑病品种的亲本选配和后代等位条带辅助选择提供依据。