幼穗无性系变异在小麦育种上的应用

冬小麦(综抗矮6号×泰山1号)F_1代花培H_1代纯系经幼穗离体培养建立的13—7管无性系获得一株R_0代种子,后代变异类型多、频率高,其R_2、R_3代株高、抽穗期都呈一个正态分布、连续性变异,调查的几个性状在R_3代稳定率已达84.85—100％。已从稳定品系中选择出一批不同株高和高蛋白材料,其中4个品系比对照冀麦6号增产17.2—35.8     

发酵木糖高产乙醇酵母菌株的选育

筛选获得的季也蒙毕赤酵母(Pichia guilliermondii)为出发菌株,采用紫外线和亚硝基胍(NTG)复合诱变,筛选高产乙醇突变株。结果表明,紫外诱变菌最佳稀释度为1×10-5,最佳照射时间为25 s;NTG诱变菌最佳稀释度为1×10-6,最佳诱变时间为40 min,经3轮紫外和亚硝基胍(NTG)交替诱变,获得高产乙醇突变株C3-10,其乙醇产量最高为13.2%,比原菌乙醇产量增加了8.05%,5次传代表现出较好的遗传稳定性。     

氮离子注入番茄M1代的生物学效应

对番茄 N+离子注入诱变效应进行了研究。结果表明 ,番茄单果重、座果数等性状变幅大、变异率高 ;而对发芽率和果实的品质性状影响较小。并以 4× 10 1 6N+/cm2 、6× 10 1 6N+/cm2 剂量处理 ,产量提高明显。但不同品系 ,不同性状的最佳诱变剂量略有不同。     

~(60)Co γ射线辐照花生种子后代的SSR分析

以辐照处理花生品种鲁花11号M2为材料,通过农艺性状调查筛选变异材料。利用107对SSR引物对7个有代表性的变异材料进行PCR扩增,分析花生辐照诱变材料的SSR遗传多态性。同时将筛选到的多态性标记用于分析原品种和诱变后代材料间的遗传相似性。结果表明,诱变材料与原品种之间存在不同程度的多态性,且呈现多个位点突变;60Co辐照诱变可使花生的DNA分子多个区段内发生重复或缺失等结构性变异,并非单纯的点突变。诱变后代材料的成对相似系数变幅为0.457～1.000,平均值为0.862;诱变后代材料与其未辐射处理对照的遗传相似系数变幅0.692～1.000,平均值为0.873。由此可见辐射可创造丰富的遗传变异,拓宽原品种的遗传基础。     

陆地棉品种γ射线诱变后代的遗传变异规律

利用250 Gy的Co60γ射线对3个棉花品种的干种子进行辐射处理,对其M4,M5农艺经济性状的遗传变异进行分析。结果表明:3个品种的辐射诱变后代M4,M5群体表型性状变异系数和遗传多样性指数均存在明显差异。阐明了辐射对不同棉花品种的诱变效果存在变异均匀度和丰富度的差异。相关分析表明,所有表型性状,以及衣分、单铃重、株高、2．5％跨长、比强度和麦克隆值等性状的M4与M5群体之间的简单相关系数都达到极显著水平。证明了诱变后代材料表型性状的变异可以遗传,M4和M5群体表型性状的遗传变异趋于稳定。3个品种诱变后代M5材料间的表型性状遗传距离变幅分别为1．83-34．68,1．26-34．55,2．22-17．05;并筛选出一系列变异明显的诱变材料。     

太空诱变红小豆后代农艺性状变异研究

本研究2005年利用第21颗返回式卫星搭载小豆品系95-0进行太空诱变处理,回收后种植,对后代农艺性状的变异规律进行观察研究并进行突变体的选择。研究结果表明,与留地对照相比,太空诱变对小豆的出苗有抑制作用,并且引起了幼苗的畸变如叶缺失、错位等现象,SP3代第二叶变异频率3.42%。太空诱变处理后小豆多种农艺性状的变异系数明显增加,并且正负向变异类型都有,表明太空诱变是创造小豆变异的有效途径。在SP2和SP3代进行选择,获得了19株剑叶形突变体、7株高株突变体、102株矮株突变体、5株粒色突变体、24株大粒突变体、70株小粒突变体和27株综合性状优良的单株,这为小豆育种提供了优良的材料和新种质,也为小豆分子遗传学研究提供了有价值的突变体。     

冬小麦品种兰天17号航天诱变后代农艺性状变异分析

为研究小麦空间诱变后代农艺性状的变异规律,用系谱法对冬小麦品种兰天17号SP 1株群、SP 2系群以及SP 2显著突变系和疑似突变系后代的表现进行了研究。结果它在SP1出现了2个显著的株高突变体D16和D38,其中D38在SP 2表现株高和主穗长度的分离,D 16在SP 2的株高与原品种对照差异不显著,但它在SP 3出现了株高和穗长的显著变异。SP 2疑似突变系D 69在SP 3出现了籽粒形态的显著突变。经单株选择,D 38的部分后代在SP 3或SP 4性状就已基本稳定。表明航天诱变小麦种子,可引起后代株高、穗长、穗形、籽粒形态等性状的变异;突变体可能出现在SP 1,也可能出现在SP 2或以后世代;这些突变体经过2～3个世代的单株选择,部分后代的性状就能基本稳定,小麦航天诱变后代农艺性状的变异符合诱变育种的基本规律。     

小麦航天诱变矮秆突变系SP_3株穗数性状观察及分析

以我国首颗航天育种专用卫星"实践八号(2006)"搭载的冬小麦邯6172为材料并以原始亲本为对照,对SP3选育出6个矮秆突变系株穗数进行观察发现:(1)株高与株穗数两性状独立遗传,通过航天诱变可对株高、株穗数二性状同时进行改良。(2)株穗数变异是双向的,其幅度为-36.95%～12.06%,方差分析达0.01极显著水平。(3)株穗数显著高于对照的变异系比例较低,占观察群体的16.67%,其余变异系株穗数等于或低于对照,分别占33.33%的比例。(4)SP3株穗数性状稳定株系比例为16.67%,并被统计分析证实,其余株系仍在分离。(5)在以株穗数为目的航天诱变后代选育中,SP3代要注重田间性状观察,依不同变异群体性状表现,可分别采取以株系为单位混合收获和以单株收获的选育方法。     

源于长穗偃麦草的小麦新品系CH7034抗白粉病基因的染色体定位

CH7034是一个兼抗小麦白粉病和条锈病的新种质材料,通过普通小麦与八倍体小偃麦"小偃7430"杂交、回交选育而成.为明确其白粉病抗性的遗传机制及抗性基因的染色体位置,用小麦高感品系"SY95-71"与CH7034杂交,所获F1、F2及其双亲在温室用白粉病E09菌系的15号小种接种,对CH7034的白粉病抗性进行鉴定和遗传分析.结果表明,无论是苗期还是成株期,CH7034对白粉病菌均表现为免疫,且具有与其抗性供体小偃7430及野生亲本长穗偃麦草相似的白粉病抗性,F1代抗病反应型为O或O'级,F2代抗感分离比符合R:S=3:1,说明CH7034抗性受显性单基因控制.用307对小麦微卫星引物对一个148株的F2群体进行分析,发现小麦微卫星标记xgwm311与抗病基因连锁,遗传距离为12.4 cM.用中国春缺-四体和双端体材料进一步验证与抗病相关的片段位于2A染色体的长臂上,进而将CH7034所含的抗白粉病基因定位于小麦的2AL上.     

60Co-γ射线对切花单头菊扦插苗的效应初探

以神马H、神马06、神马08、虹之无暇与虹之白露5个切花单头萄品种的扦插苗为试验材料,设置50Gy,75 Gy与100Gy 3个剂量的60C0-γ射线进行辐射诱变处理.结果表明,随着辐射剂量的增大,其株高、分枝数、叶片数与叶绿素的SPAD值均明显下降,成活率与开花植株数显著下降,生育期延长;5个品种的半致死剂量为33.2～62.5 Gy,平均为46.2 Gy;致死剂量为100.0～106.0 Gy,平均为101.7 Gy;切花单头菊的适宜辐射剂量约为30～40 Gy.     

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.     

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.     

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...     

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.