9个水稻品种对水稻白叶枯病(Xant homonas oryzae pv.oryzae)的抗性遗传研究

研究了8个籼稻抗病品种川植4号、川植5号、三黄占2号、二九丰、扬稻1号、75—34、83007、NT02和1个粳稻抗病品种湘虎25对水稻白叶枯病菌系P1、HB84-17或T_1的抗性遗传.这些抗病品种分别与感病品种沈农1033或金刚30杂交,所得的F_1、F_2和B_1F_1群体的抗性反应,表明8个籼稻品种对P_1和HB84-l7的全生育期抗性均由一对不完全显性的基因控制,该抗性基因与Xa-4是等位的;粳稻品种湘虎25的成株抗性则由一对显性基因控制,该基因与Xa-3相等位.     

大豆对SMV抗侵染与抗扩展的遗传分析

大豆花叶病毒（SMV）抗性研究最早着重于系统病症,后来发现感病材料还存在发病程度上的遗传差异,抗侵染与抗扩展并不相同,从而鉴别出一批具不同类型抗性的抗源。本研究利用抗侵染和抗扩展品种（系）配置10个不同类型杂交组合,在分别接种Sa或SC8株系条件下,研究两类抗性的遗传模式。结果表明,大豆对大豆花叶病毒抗侵染和抗扩展分属不同遗传体系,抗侵染由一对主基因控制,抗病对感病表现为显性;抗扩展由一对加性主基因+加性-显性多基因控制,F₂代主基因和多基因遗传率分别为23.91%~74.97% 和18.43%~37.04%,F_2∶3代主基因和多基因遗传率分别为49.46%~82.42% 和17.42%~39.93%,抗性大小依亲本而异。两类抗性都有育种价值。因中抗×高感组合的遗传率明显低于高感×高抗组合,抗扩展育种应尽量选择抗性强的品种作亲本。     

大豆对两个大豆花叶病毒本地株系抗性的遗传研究

本试验用5个抗病材料与3个丰产感病品种共配制10个杂交组合。对各组合 F_1、F_2、F_3或 BC_1世代进行了抗性鉴定,结果表明:(1)AGS-9对 S_A 或 S_C 的抗性受单个显性基因控制,不受母本细胞质的影响;(2)广吉、AGS-9、大白麻中,抗 S_A 的基因具等位性,广吉、AGS-9、徐州424、兖黄1号中,抗 S_C 的基因亦具等位性,(3)广吉 AGS-9中,     

用正反交及回交试验对黄瓜霜霉病的抗性遗传分析

本研究以黄瓜抗病自交系0023和黄瓜感病自交系112作为亲本,进行正反交试验和回交试验,分析正交F_1(0023×112)、反交F_1(112×0023)、正交F_2(0023×112)、反交F_2(112×0023),以及2个回交群体BC1(0023×112)×0023和BC1(0023×112)×112的黄瓜成株期间霜霉病田间自然发病的病情指数,分析黄瓜霜霉病的感、抗性状的遗传表现。试验结果表明黄瓜霜霉病的遗传属于细胞核遗传,受一对基因所控制,表现为不完全显性,其中感病性状为显性性状,抗病性状为隐性性状。因此,在进行黄瓜的抗霜霉病育种时应选择高抗品种作为亲本,且以早期选择为主。     

菜豆抗锈病育种研究初报

利用抗源亲本与园艺性状优良的非抗源亲本进行品种间人工杂交。根据5个杂交组合调查结果表明:菜豆抗锈遗传F_1抗病性为显性;有3个组合的抗病性受一对基因控制,F_2抗与感按3:1比例分离,另二个组合F_2抗与感按15:1或63:1比例分离,其抗病性是受两对或三对基因控制的。从80-2×30-7组合中选育出“新秀1号”和“新秀2号”抗锈新品种,表现垂直抗性。从80-4×12号玉豆组合中选育出87-2-8-1,87-1-33-2,87-1-18-2-3属于水平抗性。这些抗锈新品种(系)在秋季莱豆锈病大流行季节种植,表现出明显的增产增收效果。     

小麦核质互作抗条锈类型的发现及其遗传机制分析

在西宁小麦“天然锈病圃”,辅以人工接种天然锈菌的条件下,杂交组合冬独1号/运83—2正反交F_2对条锈抗性显著不同。正交抗性分离,反交全部感病4级。3个冬独1号作母本的组合,F_2抗条锈分离;3个冬独1号作父本的组合,F_2全部感病4级。表明冬独1号的抗条锈性具有显著的细胞质遗传特点。对冬独1号/津丰1号F_2抗条锈分离研究结果是,其抗感比经X~2测验符合孟德尔一对显性基因3:1的分离规律(P>0.8)。其互作遗传方式遵循孟德尔规律。     

普通小麦抗白粉病配合力及其与过氧化物酶的关系

选用6个亲本组配成双列杂交设计,对普通小麦抗白粉病的配合力及基因效应进行了分析。结果表明,白粉病病情指数属于数量性状遗传,符合加性—显性遗传模型,由加性效应和非加性效应共同控制,且以加性效应为主。低病情指数为部分显性。不同亲本之间一般配合力效应及含有的有利显性基因数存在明显差别。因此,选配杂交组合应在一般配合力高的基础上,注重其特殊配合力的选择。研究还表明,感病品种过氧化物酶活性高。     

水稻白叶枯病(Xanthom onas campestris pv.oryzae)抗性遗传研究 Ⅲ.两个成株抗性基因X_a-6与X_a-3的等位性分析

研究了两个品种早生爱国3号和辛尼斯对菲律宾水稻白叶枯病菌4个生理小种、日本小种1和我国菌株的成株抗性遗传和抗性基因的等位关系。这两个抗病品种与感病品种沈农1033杂交所得的 F_1、F_2和 B_1F_1群体的成株抗性反应,表明它们均携有一对显性基因。将早生爱国3号同辛尼斯杂交进行直接等位性测定,并将邳早15和蚌珠芒分别与辛     

5个抗黄萎病棉花品种的抗性配合力分析

以陆地棉的5个抗黄萎病品种为父本,4个感病品种为母本,采用不完全双列杂交配制20个组合,进行黄萎病抗性配合力研究。结果表明,冀122、中植棉2号在发病率、病情指数、相对病情指数3个性状上均具有较高的一般配合力（GCA）效应,而冀棉616、豫棉112、徐棉18号则为负向效应。通过特殊配合力（SCA）效应分析,有9个组合具有正效应,而11个组合为负效应。通过估算3个性状的GCA方差和SCA方差,表明这些性状主要受加性基因效应控制。通过遗传力分析,3个性状广义遗传力较大,可在早代选择。     

普通小麦籽粒DON含量的配合力分析

为了选育抗赤霉病且籽粒毒素含量低的小麦品种以减轻赤霉病危害,在对我国南方麦区地方品种进行赤霉病抗性鉴定的基础上,选用8个籽粒中脱氧雪腐镰刀菌烯醇（deoxynivalenol, DON）含量水平不同的小麦品种作亲本,按8×8半双列杂交配制28个杂交组合,以接种后成熟籽粒中DON含量、病小穗数、病小穗率和病粒率为指标,进行赤霉病抗性、一般配合力（GCA）和特殊配合力（SCA）遗传分析,以及不同鉴定指标间比较和相关性分析。结果表明,8个品种中籽粒DON含量以苏麦3号最低(0.5715 mg kg^-1),Alondra’s最高(13.5560 mg kg^-1),各组合F1的籽粒DON含量均低于感病品种Alondra’s。品种间GCA和SCA存在显著差异,籽粒DON含量以加性效应为主,存在部分显性效应。苏麦3号、望水白和翻山小麦表现出较好的一般配合力效应。以苏麦3号为亲本的5个组合、望水白为亲本的4个组合特殊配合力效应较大。扬麦158一般配合力效应较小,但有4个组合表现较好的特殊配合力效应。籽粒DON含量和病小穗数、病小穗率、病粒率呈极显著的正相关关系。感病品种Alondra’s和绵阳8545的各个抗性鉴定指标的一般配合力在8个品种的排序中表现一致,抗病品种各个抗性指标的一般配合力在8个参试材料间的排序有所差异。DON含量的狭义遗传力为74.54%,因此以抗DON积累为指标的赤霉病抗性育种,可以在早期世代进行选择。     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.