半配合材料VSG快速稳定棉花远缘杂种后代的研究

用激素处理和染色体加倍的方法获得陆地棉与比克棉、色伯氏棉等野生棉种的远缘杂交后代，结合杂交、回交、聚合杂交的手段，使棉花远缘杂种后代的品质性状得到了显著的提高。为了克服棉属种间杂交后代疯狂分离的难题，使新品系的性状尽快稳定，通过半配合材料VSG作母本与之杂交，得到远缘杂种后代低代材料的单倍体，通过染色体加倍等手段得到了稳定的优质棉新品系。     

陆地棉不同群体主要性状的遗传力及杂种优势分析

以1个高强纤维品系为父本,6个常规棉品系、5个转Bt基因抗虫棉品系和5个彩色棉品系为母本配制杂交组合,利用AD模型,分析了3个群体杂交组合主要性状的遗传力和杂种优势表现。结果表明,常规棉群体和抗虫棉群体的衣分、籽棉产量等性状基因显性效应对杂种一代性状形成起主导作用,彩色棉群体的籽棉产量受加性和非加性效应共同控制,而衣分的遗传变异主要来自基因的加性效应。常规棉群体的比强度以显性效应为主,抗虫棉和彩色棉群体的比强度以加性效应为主。3类群体中2．5％跨长和马克隆值的遗传效应均以加性效应为主,同时受非加性效应的影响也较大。常规棉群体和抗虫棉群体的产量性状有一定的杂种优势,纤维长度和细度基本上没有优势,纤维强度有显著的负优势,但彩色棉群体的纤维长度和强度有一定的正向优势。因而,在品种改良上,可以利用常规棉和转基因抗虫棉的杂种优势大幅度提高产量,利用彩色棉的杂种优势来提高纤维品质。     

彩色棉品系的SSR分子变异研究

采用SSR分子标记技术对来自12个组合的62份稳定彩色棉新品系进行分子变异分析。结果表明,从242对SSR中筛选出的29对多态性引物在供试材料中共扩增出198个标记。其中,多态性标记115个,占总标记数的58.1%,这些引物能较好地揭示彩色棉的变异位点。MGHES-6引物扩增的多态性标记最多,其次为BNL2960、CM43和MGHES-66。29对SSR引物的PIC值变化在0.493～0.938之间,平均0.790,说明彩色棉SSR等位基因丰富度较高。基于SSR数据的聚类分析,可将62份新品系分为两大类,一类是由彩色棉种质资源经系统选育获得的材料,另一类是通过杂交选育获得的材料。     

转基因抗虫棉sGK9708与不同类型品种杂种的遗传及优势分析

利用转基因抗虫棉sGK9708与7个常规棉、7个优质棉、8个转Bt基因抗虫棉和6个彩色棉品系分别配制杂交组合,对其性状的遗传效应和杂种优势进行了比较分析。结果表明:(1)常规棉、优质棉和转基因抗虫棉类型的子棉产量以显性效应为主,加性效应也起较大作用,纤维品质性状的遗传变异主要来自于加性效应。(2)彩色棉类型的子棉产量性状以加性效应起主导作用,纤维品质等性状的遗传变异受显性和加性效应共同控制。(3)转基因抗虫棉类型的衣分和铃重具有极显著的显性效应,常规棉类型以加性效应为主导,优质棉和彩色棉类型由加性和显性效应共同决定。(4)彩色棉类型的子棉产量性状具有负向群体超亲优势,纤维长度和强度具有一定的正向群体超亲优势。     

棉花半配合材料 VSg-1的选育及其育种应用研究

从美国引入的海岛棉(Gossypium barbadense L.)半配合材料 VSg~(**),经过八年的选育和加倍,培育出适合我国气候的新品系 VSg-1。单倍体遗传频率达到69.9%。棉花半配合材料 VSg-1,已初步成功地应用于单倍体育种。已获得陆地棉(Gossypiumhirsutum L.)四个杂交组合育种初代材料的单倍体和少量加倍单培体种子。     

染色体加倍新技术

染色体加倍新技术小麦染色体加倍技术是小麦单倍体育种和远缘杂交的重要技术措施。单倍体植株染色体加倍后可获得纯合二倍体,用作遗传研究或筛选优良品种。远缘杂交F1染色体加倍后,可获得异源双二倍体,创造新物种或用农艺性状好的亲本回交,选育具外缘优良基因的新种……     

天然彩色棉研究进展与发展前景

由于天然彩色棉纤维色素受遗传基因控制,性状表现为不完全显性单基因控制,造成了天然彩色棉纤维品质不及白色棉,也给天然彩色棉颜色创新带来了一定的难度;提出今后天然彩色棉发展的趋势要加强基础理论研究、加快材料创新、育种手段创新。常规育种与生物技术的密切结合是未来天然彩色棉研究的方向,将促进天然彩色棉纤维品质改良和颜色创新,推动天然彩色棉产业化的发展。     

国审优质高产加甜糯玉米品种桂甜糯525选育研究

针对产业结构的调整及满足玉米消费市场的需求,在新的育种目标指导下,通过杂交组配,选育出甜玉米和糯玉米风味兼具的超甜型糯玉米新品种桂甜糯525,为优化广西及我国东南玉米栽培区的品种结构提供优选品种。利用自选自交系YL 611作母本,超甜糯双隐自交系WT 1791作父本进行杂交,使目标性状得到有效组合。亲本材料的选育采用系谱法和多代单株选择法,并进行配合力测试、品系比较和品种比较,稳定组合在不同环境进行鉴选,使杂种基因型的各种性状得到充分表达和有效筛选。育成的玉米新品种桂甜糯525具有质优、高产、广适等特点。     

利用甘蓝型油菜与白菜类蔬菜近缘种间杂交创造早熟油菜新种质

为拓宽甘蓝型油菜遗传基础,解决甘蓝型油菜育种中早熟资源贫乏的问题,利用甘蓝型油菜(Brassica napus,2n=4x=AACC=38)与白菜类蔬菜(Brassica campestris,2n=2x=AA=18)的大白菜、小白菜和紫菜苔进行杂交,采用系谱法,经过连续10 年的选择,培育出10 个稳定的早熟优良品系,代号D1~D10。这些新种质的生育期比对照早2.5~9.5 天,品质符合国家双低油菜标准,农艺性状各具特色。由于新种质拥有白菜A染色体的遗传背景,在杂交组合测配中,用这10 个新种质比用非新种质材料配制杂交组合早熟,且获得高产组合的概率高出1倍以上。     

野生棉与陆地棉异源四倍体的合成与性状鉴定

棉属具有丰富的种质资源,将抗病性从野生棉转移到陆地棉中,以此提高陆地棉抗病性是一条理想的育种途经。本研究通过陆地棉和C组野生澳洲棉远缘杂交获得杂种F1,对其进行染色体加倍,将加倍的异源六倍体再与B组野生绿顶棉杂交,产生陆地棉、澳洲棉、绿顶棉的异源四倍体杂种。异源四倍体杂种继承了亲本的部分性状,同时也产生了如蔓生等特异性状;该杂种减数分裂后期染色体不能均等分离,四分体时期有多分体和微核出现;SSR结果发现,该杂种不仅具有三个亲本的特征条带,并且产生了新的重组成分。本研究不仅为该异源四倍体杂种不育提供了直接原因,也为进一步探讨有效的育性恢复方法及棉花新种质创制提供了依据,同时为利用野生棉资源控制棉花黄萎病育种探索培育了中间材料。     

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.