杂交油菜制种保纯措施

1影响杂交油菜种子纯度的因子 1．1种子变异 杂交油菜种子生产采用的是三系配套法,在三系种子生产过程中,不育系、保持系、恢复系都可产生变异,造成亲本种子不纯,用不合格的亲本种子制种,直接影响了杂交F1代的纯度。     

河西走廊Ogura CMS三系杂交油菜制种优势和技术流程

河西走廊由于具有天然的自然环境和地理优势,被称为是"天然的种子生产车间"和"天然的种子仓库",其是甘蓝型冬油菜制、繁种的良地。从Ogura CMS三系杂交油菜种的自身特点以及河西走廊地理、气候特点,讨论了Ogura CMS三系杂交油菜在春播区的制种优势和制种技术。     

两系杂交油菜种子全程质量管理技术

对于种子企业而言,生产合格的油菜种子来规避质量风险,不仅是油菜制种工作的重点和难点．更是油菜品种产量潜力能否得到充分发挥的前提和保证。两系杂交油菜制种因其母本特有的育性分离．增加了制种工作的难度和强度。要确保两系杂交油菜制种的质量,不仅仅需要种子企业员工统一思想认识．更需要制定出严格的质量管理规程。明确各方面的职责．充分调动各方面尤其是制种基地干部群众参与质量管理工作的积极性和主动性．认真做好油菜种子全程质量管理．     

两系杂交油菜高产制种技术研究

两系杂交油菜制种的主要缺点是细胞核雄性不育系用兄妹交繁殖后，不育株率只能保持在50％左右，制种时必须在开花前拔除占母本群体50％的可育株，投入的人力和物力较大，生产成本较高。但两系法在彻底清除可育株和严格的隔离条件下，制种的纯度可达99％以上，能保证杂交种的质量。因此，两系杂交油菜制种仍然是目前大面积生产上常用的杂交油菜种子生产方法。本文研究在保证两系制种纯度和种子质量的前提下，如何提高大面积两系杂交油菜制种产量，为农民增产增收提供理论依据。     

浅议杂交水稻制种技术的创新与发展

杂交水稻种子需要年年制种生产,以确保子一代的杂种优势。当前,我国已建立了成熟的种子生产技术体系,但是基于劳力密集型的种子生产技术操作程序繁杂、劳动强度大,滞后于现代农业,迫切需要创新制种技术。应发展新型轻简的全程机械化制种技术,以及父母本混播混种和杂种优势固定(第三代杂交水稻和一系法杂交稻)的种子生产技术,以助推杂交水稻种业的发展。     

提高杂交油菜制种质量和产量的措施

杂交油菜制种技术较复杂 ,中间环节多 ,易受外界环境的影响 ,因而对制种环境、媒介和亲本都有严格要求。下面分别谈谈影响杂交油菜制种质量和产量的因素 ,及其可采取的相应措施。1　影响杂交油菜制种质量的因素1.1　亲本配合力 :杂交油菜制种需要不育系、保持系、恢复系三系共同作用才能完成 ,若亲本选择不严格或越代使用 ,使亲本间配合力降低 ,则会导致所制得的杂交种子纯度降低 ;若保持系的保持能力不够 ,则会使用于制种的不育系的不育率和不育度都较差 ,出现大量的半不育株和正常花株 ;若恢复系的恢复能力较差 ,则会使所制得的杂交种子中…     

化学杀雄剂对油菜三系杂交制种母本微粉控制试验简报

三系杂交油菜制种母本微粉的产生是影响F1代种子纯度的关键因素。秋播油菜三系制种通过“旱、薄、迟、密”等农艺措施很难消除母本微粉的产生。微粉的产生量与油菜花期天气的好坏有着极为密切的关系。笔者通过近5年系统试验，明确了化学杀雄剂对陕2A微粉控制效果；选配了复配型化学杀雄剂在现蕾期处理母本、控制微粉效果均在80％以上；F1代种子纯度较ck均能提高10个百分点以上；种子纯度均在83％以上。从而探讨了一条三系杂交油菜制种微粉的控制由“天控”向“人控”的转变途径。     

提高甘蓝型三系杂交油菜制种种子纯度和产量的措施

甘蓝型油菜制种不育系对低温、水分较为敏感,尤其对秋播制种油菜在春季初花期易产生微粉自交结实,影响种子纯度。勉县是陕西省杂交油菜生产基地之一,多年来一直研究解决制约杂交油菜制种高产和确保种子纯度这一矛盾,在总结1996年杂交油菜秦油二号制种纯度下降、转商损失300万元这一严重教训的基础上,从1997年秋播开始,做了以下试验工作,收到了十分明显的效果,现总结如下。1采用旱地、迟播、密植、控肥技术,搭好制种油菜丰产苗架1.1改平坝水田油菜制种为丘陵旱地制种由于平坝油菜制种多为水田,土壤湿度大,含水分高,油菜长势旺,难以控制水肥,…     

杂交水稻种子生产教学重点探讨——种子生产学授课体会

文章从杂交水稻种子生产的特点,两类雄性不育系的遗传特点及在种子生产中可能遇到的问题,杂交稻亲本几种原种生产方法的特点和应用,杂交水稻制种的共性技术,三系、两系制种及籼稻、粳稻制种的差异等5个方面,介绍了《种子生产学》有关杂交水稻种子生产部分的授课体会。     

杂交油菜湘杂油3号制种技术

湘杂油 3号是常德市农科所和湖南亚华种业科学研究院利用秦油 2号不育胞质选育而成的甘蓝型油菜三系杂交种。在常德市油菜区试和湖南省油菜区试中分别比对照中油 82 1增产 31.8%、17.13% (均达到极显著水平 ) ,2 0 0 1年通过湖南省品种审定委员会审定。由于湖南地处长江中游以南 ,春季气温不稳定与胞质不育系遇低温产生微量花粉这一矛盾成为杂交制种的主要难点 ,制约了本地区杂交油菜种子生产和推广。为此 ,我们经过多年试验探讨 ,以延迟初花期控制不育系微粉为重点 ,以规范其它配套措施为保证 ,在制种产量和质量上取得了较好的效果。技术要…     

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.     

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.     

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.