水稻籼粳杂种不育性及其类型

克服栽培稻不同亚种间杂种F1的不育性是有效利用亚种间杂种优势的前提.本研究选择了籼粳两亚种不同生态型的19个水稻品种作为试验材料,研究了它们之间杂种不育性的表现特点及遗传特性.试验按p×q设计进行,以籼稻作为母本,共配置了90个籼粳交组合.调查了各组合F1的小穗育性和花粉育性.研究结果表明:(1)各组合的小穗育性和花粉     

(禾鲁)稻与云南稻地方品种亲缘关系的初步研究

穭稻的植株形态及谷粒特性与云南稻的两个粳型地方品种相近,彼此的杂交结实率高于它与籼型品种的杂交结实率。穭稻野生性状较强,在 F_1代中表现显性.F_1植株的花粉育性为1.15—82.1%,与粳型品种杂交时育性较高,又以穭稻为母本时育性高于其反交组合。穭稻种胚酯酶同工酶的酶带与云南稻的粳型品种有些相近。穭稻与云南稻四个品     

水稻亚种间杂种F_1的籼粳属性鉴定

采用程氏指数法对用4个籼稻和3个粳稻按完全双列杂交设计配制24个籼粳杂交组合的F_1进行籼粳属性鉴定,结果表明,所有水稻亚种间杂种F_1都表现偏籼和偏粳,并且偏籼多于偏粳,但没有一个完全表现为粳型和籼型的。母本的亚种类型对杂种F_1的籼粳属性有一定影响,也就是说,用籼稻母本容易获得(偏)籼型亚种间杂交水稻,反之亦然。该文还对用作鉴定籼粳属性的6个鉴别性状在亚种间杂种F_1表现进行探讨。     

水稻籼粳亚种间杂种不育性的研究进展

克服杂种不育性是利用籼粳亚种间杂种优势的关键。由此对水稻亚种间杂种不育性的原因、细胞学基础及两种主要基因遗传模式进行了总结,并详细综述了利用“亲和基因”克服籼粳杂种不育性的两种有代表性的学说-广亲和基因和特异亲和基因分子定位的最新研究进展,并提出了两“亲和基因”共同利用的初步设想:将聚合了Si等位基因的粳型亲籼系与聚合了不同广亲和基因(中性亲和基因的广亲和力强、亲和谱广泛的粳型品种进行杂交和回交,选育出聚合不同广亲和基因和Si等位基因的粳型亲籼系,再与籼稻品种杂交,真正实现直接利用籼粳亚种间杂种优势。     

水稻粳型亲籼系S-c座位基因型分析

S-c是控制水稻籼粳亚种间杂种F1花粉不育性的基因座位之一。在该座位,台中65的基因型为Sj/Sj,广陆矮4号的基因型为Si/Si。以台中65和广陆矮4号为遗传测验种,分别与4个粳型亲籼系配组,根据部分F2群体中植株花粉育性表型及与S-c紧密连锁分子标记基因型的偏态分离程度,测定了这4个粳型亲籼系在S-c座位的基因型,结果表明,G2416-3的基因型为Si-2/Si-2;G2605和G3004-4的基因型均为Si-1/Si-1;G2417-2-1的基因型为Sn/Sn。本文还对F1花粉不育性基因遗传分化的测定方法进行了讨论。     

籼粳亚种间杂种育性相关基因座全基因组分析

利用一套以粳稻品种Asominori为遗传背景、籼稻品种IR24为染色体片段供体的覆盖全基因组的CSSL群体，研究了籼粳亚种间组合Asominori/IR24和02428/IR24杂种小穗低育性的遗传基础。结果发现，Asominori/IR24组合的育性主要受第5染色体上的2个育性位点S-24(t)和S-31(t)及第6染色体上的 S-5位点控制，其中S-31(t)为本研究发现的新育性位点，粳稻品种02428带有该位点的亲和性基因。02428/IR24组合的低育性主要受S-24(t)花粉育性位点的影响。育性基因的表达受遗传背景的影响，在粳稻遗传背景中，S-24(t)位点处在Sⁱ/S^j杂合基因型时可使杂种小穗育性下降70%左右，而S-31(t)和 S-5为杂种半不育位点。在籼粳全基因组杂合遗传背景中，当S-5ⁱ/S-5^j基因型置换成S-5ⁱ/S-5ⁱ基因型后，亚种间杂种小穗育性可平均提高22.5%，接近正常育性水平。在S-5ⁱ/S-5^j遗传背景中，S-24(t)和S-31(t)的Sⁱ/Sⁱ纯合基因型不能改善亚种间杂种的小穗育性。说明S-5位点是影响亚种间小穗育性的关键位点，在亚种间杂交稻育种中，必须首先克服S-5位点造成的育性障碍。提出了等位基因置换法克服水稻籼粳亚种间杂种小穗低育性的技术策略。     

36个水稻骨干系的分子聚类及其遗传育种学意义：I分子标记多态性与杂交亲和

对３６个水稻骨干系进行了ＲＦＬＰ分析，并对这些水稻材料的１６２个杂交组合育性进行了分组分类研究。杂种育性的遗传基础研究表明，亚种内杂交组合育性显著高于亚种间杂交组合育性。亚种间杂交不育性是由籼粳两个亚种间深刻的遗传分化引起的。     

水稻特异亲和基因S-e的分子定位

水稻籼粳亚种间杂种具有强大的优势，但亚种间杂种的不育性限制了这一优势的利用。开展杂种不育基因的定位工作，对于进一步了解杂种不育性的遗传基础，克服亚种间杂种的不育性具有重要的意义。本研究选用粳型品种台中65的近等基因系E47-1和籼型品种广陆矮4号为材料，利用74个SSR标记对杂种F2群体进行偏态分离标记的筛选，同时根据F2和F3群体花粉育性和具有偏态分离的SSR标记之间的连锁关系，对特异亲和基因(F1花粉不育基因)S-e座位进行了分子定位，取得了以下主要结果：1、利用116个均匀分布在水稻12条染色体上的SSR标记对籼粳两亲本进行多态性筛选。结果有101个SSR标记在亲本间具有多态性，15个SSR标记在亲本间无多态性，SSR标记在亲本间的多态率高达87．07％。2、选用74个亲本间具有多态性的SSR标记对E47-1／广陆矮4号组合F2群体的偏态分离进行了初步的筛选和分析。发现有6个染色体区段的9个SSR标记在F2群体中存在偏态分离，它们分别位于第3、第6、第7、第10、第11和第12染色体上，卡方值均达到显著或极显著水平。6个染色体区段中有2个严重偏态分离区段，分别位于第6和第12染色体。3、通过对F2群体的花粉育性和偏态分离区段的SSR标记基因型的相关关系分析，表明位于第12染色体上的SSR标记RMl9附近存在一个F1花粉不育基因。继而在该标记附近设计位置特异性微卫星标记PSM401、PSMl80、PSMl82，利用F3作图群体，将特异亲和基因S-e座位定位在分子标记PSM401、PSMl80和PSMl82、RMl9之间，该基因与各标记的遗传距离分别为2．3cM、1．3cM、3．7cM和4．3cM。4、选取在S-a、s-b、S-c、S-d、S-e五个座位均纯合、花粉表现为部分不育的F2单株，发展了另一R群体，表明该群体存在另一特异亲和基因座s-f。本研究利用SSR标记，对特异亲和基因S-e进行了分子定位。S-e座位的分子定位，进一步丰富和完善了特异亲和性的学术观点，并为分子标记辅助选育水稻的粳型亲籼系奠定了基础。     

开花期低温胁迫对四川攀西稻区水稻开花结实的影响

以3种籼稻品种和3种粳稻品种为试验材料, 利用人工气候室在开花期进行低温胁迫处理, 研究了低温胁迫对攀西稻区籼、粳稻开花和结实及两者间关系的影响。结果表明, 开花期低温胁迫下籼稻和粳稻的开花习性、花药和花粉特性和结实表现不同。常规粳稻开花对低温有较高的耐冷性。低温胁迫下籼稻品种(组合)花药体积、花药开裂率、可育花粉率、柱头着花粉数和柱头花粉萌发率较对照降低幅度均比粳稻品种(组合)大; 籼稻品种(组合)各产量构成因素较对照降低幅度比粳稻品种(组合)大。相关分析表明, 结实与水稻花药和花粉主要性状有密切关系。开花期低温胁迫影响花药和花粉发育成熟, 使花药不能正常开裂、散粉不足, 可育花粉率和柱头花粉萌发率降低, 直接影响受精结实, 成为结实率降低的主要原因之一。     

36个水稻骨干系的分子聚类及其遗传育种学意义 Ⅰ分子标记多态性与杂交亲和性关系的研究

对３６个水稻骨干系进行了ＲＦＬＰ（限制性内切酶长度多态性）分析，并对这些水稻材料的１６２个杂交组合育性进行了分组分类研究。杂种育性的遗传基础研究表明，亚种内杂交组合育性显著高于亚种间杂交组合育性。亚种间杂交不育性是由籼粳两个亚种间深刻的遗传分化引起的。广亲和性品种为亲本之一的杂交组合多数（７１．７％）具有正常的育性，ＲＦＬＰ分析表明，这些杂交组合的遗传基础特殊，其遗传距离大于典型的亚种内组合距离，而小于典型的亚种间遗传距离。广亲和性水稻种质的创建、改造和利用潜力是大的，广亲和基因作用及其与杂种优势表现有关的若干遗传育种学问题要协同一并去解决。     

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.