小麦新种质YW243抗条锈病新基因的AFLP标记

小麦新种质YW243抗条锈病新基因对条锈菌具有较宽抗谱，对26个不同毒性谱的条锈菌菌系免疫到近免疫，与已知基因系抗病谱不同，可能为新的基因或基因组合。遗传分析表明，YW243对条锈菌条中31号小种的抗性由显性单基因YrX控制。通过BSA法对1056对MseI/EcoRI AFLP引物进行筛选，结果表明7对引物可扩增出多态性片段，通过对F2群体单株遗传连锁分析和作图软件分析，结果表明，2个AFLP 标记M54E63-700、M54E64-699与YrX连锁较紧密、遗传距离为9.27 cM，为该基因的精细作图和分子标记辅助育种打下了一定基础。     

小麦新种质YW243白粉病抗性鉴定和遗传分析

利用病菌接种鉴定、抗性遗传分析、基因推导和STS方法,对抗白粉病小麦新种质YW243进行鉴定.YW243高抗我国白粉病菌毒性级别在7级以下、毒性频率占90%以上的生理小种,抗性有效,可在我国大部分麦区使用.与感病品种中国春、京771测交的F2抗感分离符合3∶1比例,证明YW243对白粉病的抗性由1对显性基因控制.基因推导、抗性遗传分析     

意大利小麦品种资源抗条锈性鉴定

１９９６年对５２份意大利小麦品种进行抗条锈性分小种接种鉴定和田间抗病性及农艺性状观察试验,结果表明成株期表现抗条锈病的有２３份,对条锈菌新优势生理小种条中３０、３１号表现抗病的有３７份。结合农艺性状观察和田间抗条锈病、抗白粉病表现,筛选出了普通小麦Ｐａｓｃａｌ等１３份抗病性强、农艺性状较好的材料。     

小麦品种“高优503”抗条锈基因染色体定位

本试验利用感染条锈病的“中国春”单体系列与抗条中29号生理小种的“高优503”小麦进行杂交，通过细胞学观察和田间锈病鉴定，对其抗病基因进行单体分析。结果表明：“高优503”小麦抗条中29号生理小种的基因位于4B和5B染色体上，是两对显性基因。     

小麦抗源兴资9104抗条锈性遗传研究初报

采用常规杂交和基因推导法相结合,在苗期和成株期对小麦优良抗病种质兴资9104进行抗条锈性遗传研究。结果表明,兴资9104至少含有1对显性全生育期抗条锈病基因和1对成株抗条锈病基因,分别控制对条锈菌生理小种条中17号的全生育期抗性和对条中32号的成株期抗性。兴资9104可能携带有YrSK基因。建议在小麦抗病育种中     

后条中32时期我国小麦条锈抗源之现状

用条中(CY)29、 31、 32号生理小种对6类抗性材料进行了苗期分小种和成株期混小种鉴定. 结果表明, 除Yr5、 10、 15外, 还有一些Yr基因和许多抗病材料目前在我国仍表现抗病. 加强对这些抗源材料的研究与利用将能缓解当前条锈病抗源贫乏的危机.     

高寒区小麦条锈病的发生与防治技术

<正>小麦条锈病喜湿润凉爽气候,怕高温,对南北方小麦均可造成为害。该病的生理小种变化很快,目前由条中1号变为条中31、32号,使小麦品种极易丧失抗性,2～3年病害就会中度或偏重发生流行1次。常造成小麦籽粒秕     

甘肃省小麦条锈菌流行小种的RAPD标记

本研究利用160条随机引物,对甘肃省小麦条锈菌(Puccinia striiformis f.sp.tritici)8个主要流行生理小种进行了RAPD片段的筛选,最终找到了4个流行生理小种条中32号、条中33号、Hybrid46-8号、shui-4的特异性RAPD标记,分别为S301、S19、S39、S36和S2140。结果表明:通过寻找小麦条锈菌生理小种的特异性RAPD片段,能从分子水平准确、快速检测小麦条锈菌各生理小种。     

几个大穗抗病的国外小麦种质资源

1983年以来,中国农科院作物所安阳小麦研究室引进了智利、墨西哥、美国、土耳其、罗马尼亚、南斯拉夫等国外小麦种质资源651份,经过田间调查和抗病性鉴定(条锈病接种的生理小种为条中17、18、20、23、25、27、28号的混合菌种,叶锈病接种的生理小种为叶1、叶2、叶3、植17、植20的混合菌种),筛选出一批综合性状好、可供育种利用的材料,现重点介绍几个大穗抗病材料在本室原始材料圃内的表现。     

抗病小麦种质C39的评价与利用

引自英国的Ｃ３９,经多年田间观察,在人工诱发条锈病的条件下,对目前提供给育种单位的所有条锈病生理小种（包括条２１、条３１、水源１１５、水源１１１３、杂４６）均表现免疫。尤其指出的是,自１９９７年新增了强毒性条锈菌生理小种后,我们以往利用的中抗和高抗条锈病的抗源几乎全部丧失抗性,而Ｃ３９仍表现免疫。近年来,小麦白粉病在黄淮地区逐年加重。从育种考虑,Ｃ３９也是一个优良的抗白粉病育种亲本。至今,在安阳地区尚未发现它感染白粉病。张庆勤（贵州农学院）等人曾在小麦白粉病重发区贵州对Ｃ３９作过抗性鉴定,肯…     

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.     

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...     

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.     

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.