普×爆自交高代选系的配合力及利用价值研究

以24个普×爆自交高代选系和7个爆裂玉米骨干自交系按NCⅡ遗传交配设计组配成的168个单交组合为材料,对3个膨爆特性指标和12个主要农艺性状进行了配合力分析。结果表明,BP02,BP03,BP04,BP12,BP14等选系主要性状的GCA较高,应进一步利用这些选系与爆裂玉米自交系广泛测交组配利用;BP20,BP21与N03,BP02与F2,BP11与N16穗粒重和膨化倍数的SCA效应均为较大极显著正值,应进一步利用这些选系分别与其父本的同类群近缘系进一步测配,从中筛选优良组合;24个选系的聚类结果与其亲本和系谱来源不存在必然联系;所有测交组合的综合性状较对照豫爆2号无明显优势,作为普通型爆裂玉米杂交种在生产上的利用价值不大。     

连续自交对爆×普玉米选系膨爆特性的选择效果

对11个爆×普玉米组合连续进行6代自交选择，测定分析了17个入选系51个单穗的膨爆特性。结果表明自交选择对膨爆特性改良的效果不佳；不同爆×普组合间及同一组合不同选系间、同一选系不同单穗间的膨爆特性均存在显著差异；爆×普选系测交后代产量优势明显，膨爆特性存在显著差异。同时还对爆×普后代选育方法问题进行了讨论。     

爆裂玉米产量及膨爆特性遗传效应分析

以12个爆裂玉米自交系间杂交F1为材料,采用三倍体胚乳模型对子粒膨爆特性及穗粒重、百粒重的3类遗传效应研究结果表明,3项膨爆特性指标同时受到直接效应和母体效应2种遗传体系所控制,百粒重和穗粒重由3套遗传体系所决定。穗粒重、百粒重、爆花率和膨化体积以普通直接遗传率为最主要分量,膨化倍数的普通母体遗传率最高。各自交系的直接加性效应和母体加性效应的显著性不同,要注意不同自交系的恰当组配。     

普×爆F2代膨爆特性的分离特征研究

对两个普×爆组合F2代群体膨爆特性的分析结果表明，F2代膨爆特性较差，采用常规系谱法从中选育出优良爆裂玉米自交系的机率较小；膨爆特性可能是由主效基因存在的多基因控制的数量性状；各性状间多呈显著或极显著正相关，膨化体积对膨化倍数的直接正向作用最大，百粒重的直接负向作用最大，穗粒重和爆花率主要通过膨化体积起正向间接作用。     

普×爆自交和回交后代连续选择效果研究

对4个优良普×爆组合连续选优后代F3,F4,F5,BC1S1,BC1S2,BC1S3,BC2S1,BC2S2和BC2S3的爆花率、膨 化倍数、穗粒重和百粒重的分析结果表明:各世代不同组合穗粒重和百粒重的平均值、变异系数以及优于亲本的植株 数均存在较大差异,而爆花率和膨化倍数的差异较小;回交后代连续自交较直接连续自交穗粒重和百粒重有所减小, 而爆花率和膨化倍数增大;各世代所有性状均存在较大变异,且以穗粒重最大,爆花率最小,而且随着选择世代的增 加,穗粒重和百粒重均明显减小,而爆花率和膨化倍数明显增大;各世代爆花率和膨化倍数与爆裂亲本多呈显著或极 显著正相关,而穗粒重和百粒重与亲本多呈显著或极显著负相关。     

爆裂玉米距离分析与杂种优势

根据80个爆裂玉米自交系数量性状的表现估算了它们之间的遗传距离，又估算了由其中49个自交系间随机组配的67个杂交组合F1代小区产量、爆粒率和膨胀倍数的杂种优势。相关和回归分析表明，F1代产量的对照优势与其双亲间的遗传距离呈显著的二次曲线关系，而F1代品质特性爆粒率和膨胀倍数的对照优势与其双亲之间的遗传距离无确定     

爆裂玉米膨爆特性的遗传及杂交种选育研究进展

综述了爆裂玉米膨爆特性的遗传及其与穗粒性状的相关性、爆裂玉米的育种方法等方面的国内外研究进展。爆裂玉米的膨爆特性是由多基因控制的数量性状，与籽粒产量及大多数穗粒性状呈显著负相关。通过不同爆裂玉米间相互杂交及其与普通玉米杂交、回交或长期的轮回选择，可有效地聚集分散在不同材料、不同个体中的优良性状和有利基因，显著提高育种效果。     

玉米杂交分离群体的膨爆特性分析

为了揭示爆裂玉米膨化性状的遗传特征,利用8个玉米自交系杂交组配的F₁分离群体为材料,测量了群体的膨爆特性以及百粒重、百粒体积等性状,通过相关分析和通径分析揭示各性状相互关系。结果表明：群体各性状变异系数均较大,变幅为16.56%~78.18%;膨化倍数与膨化体积、爆花率均呈极显著正相关,而与百粒重、百粒体积呈极显著负相关;膨化体积对膨化倍数有较大直接正效应,而百粒重对膨化倍数有较大直接负效应。本研究可为爆裂玉米膨爆特性遗传改良提供参考。     

爆裂玉米3个膨爆特性的非条件和条件QTL分析

膨化倍数(PF)、膨化体积(PV)和爆花率(PR)是爆裂玉米的主要品质指标。本研究以普通玉米自交系丹232和爆裂玉米自交系N04杂交构建的259个F2:3家系为定位群体,采用完全随机区组设计在郑州夏播条件下测定了3个膨爆特性指标。利用覆盖玉米10条染色体的183对多态性分子标记构建连锁图,采用复合区间作图(CIM)方法对各性状进行非条件QTL定位分析,采用条件遗传统计软件对PF进行条件QTL分析。3个膨爆特性指标非条件QTL定位共检测出31个QTL,单个QTL的贡献率为3.09%￣12.46%,累计贡献率为51.90%、77.37%和61.45%。在8个标记区间(占42.11%)同时检测到控制2￣3个性状的QTL。加性和部分显性在膨爆特性的遗传中起主要作用,同时存在显性和超显性基因效应。条件QTL定位结果表明,PV和PR以不同方式显著影响PF的QTL表达,PV比PR更重要。     

利用SSR标记划分爆裂玉米杂种优势群的研究

利用113对SSR多态性引物研究了来源比较广泛的56个爆裂玉米自交系的遗传多样性，并初步进行了杂种优势群划分。结果表明：供试自交系问存在较丰富的SSR多态性；56个爆裂玉米自交系可划分为6个杂种优势群，其中Ⅰ，Ⅴ，Ⅵ类群以国内种质选系为主，Ⅱ，Ⅲ，Ⅳ类群主要为外引杂交种选系，第1类群又可分为3个亚群。该分群结果与杂交组合的组配效果相吻合，高优势组合的亲本均属于不同的优势类群(亚群)，而在类群(亚群)内未组配出优良组合。SSR标记可以用于研究爆裂玉米自交系的种质基础。     

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...     

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.     

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.     

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.