灰色关联度对改良后CIMMYT群体自交系产量与相关性状的分析

采用灰色关联度分析方法,分析了改良后CIMMYT群体优良自交系产量（单株粒重）与主要农艺性状的关系。结果表明：总体关联顺序为穗重 > 行粒数 > 出籽率 > 穗位高 > 穗长 > 株高 > 百粒重 > 穗行数 > 秃尖长。因此,提高穗重、行粒数、出籽率的同时也具有适当的株高和穗位高,有利于得到产量较高的玉米自交系。本试验利用改良后CIMMYT群体优良玉米自交系,明确了主要农艺性状对产量的贡献,为选育高产玉米自交系提供了理论依据。     

玉米‘黄早四’改良系改良研究探讨

旨在为优异玉米自交系改良及其杂交种选育、玉米种质创新提供科学依据。本研究选用‘黄早四’、‘昌7-2’、‘西农672’等11个玉米自交系,采用NCⅡ不完全双列杂交设计,人工配制成30个杂交组合作为试验材料。田间试验采用随机区组设计,性状田间调查和室内鉴定相结合,试验数据采用SPSS软件LNT进行分析。结果表明：（1）‘黄早四’自交系各性状一般配合力普遍较低,负向效应明显大于正向效应,只有株高、穗位高、叶面积系数表现为正向效应。（2）‘昌7-2’各性状一般配合力较‘黄早四’均有明显提高,株高、穗位高、叶面积系数、穗行数、行粒数、出籽率和产量均表现出正效应值;而穗长、结实长、百粒重表现出负向效应。（3）‘西农672’穗长、穗行数、结实长、行粒数和产量都有较高的正向效应,但百粒重、出籽率表现为负向效应,株高、穗位高、叶面积系数表现与‘昌7-2’和‘黄早四’相反,表现负效应值。由此可见,高基点自交系受体、供体组材、不断导入新的优异玉米基因,充分利用加性遗传方差、累加提高优异玉米种质的基因频率是新优玉米自交系选育的关键。     

12个玉米群体的主要农艺性状与产量、品质的灰色关联度分析

为了明确玉米群体主要农艺性状与产量、营养品质的关系,应用灰色关联度分析方法对12个玉米群体的主要农艺性状、产量、营养品质等进行了灰色关联度分析。结果表明:与产量密切相关的农艺性状是出籽率、行粒数、穗粗、百粒质量、株高等;与粗蛋白、粗脂肪、粗淀粉和赖氨酸含量等营养品质密切相关的农艺性状是穗粒数、百粒质量、行粒数、出籽率、穗行数等。根据玉米群体主要农艺性状间的灰色关联度关系,说明在玉米群体产量、营养品质改良的过程中,在保证适当株高的前提下,要注重选育出籽率、百粒质量较高品种,同时不要忽略对玉米群体穗行数、行粒数、穗粗的选择,为选育高产、优质玉米新品种提供科学依据。     

玉米自交系表型性状与产量的灰色关联分析

以257份玉米自交系为材料,采用灰色关联分析方法,对影响玉米自交系产量(单株粒重)的主要表型性状进行研究。结果表明:关联序排在前三位的是全生育期、散粉期与吐丝期,生育期是影响玉米自交系单株粒重最重要的因素,其他性状与单株粒重的密切程度依次减小;与产量相关的主要性状中,关联序排在前三位的是穗位、穗长、百粒重;总体排序为全生育期>散粉期>吐丝期>穗位>穗长>百粒重>全株叶数>株高>穗位叶面积>穗粗>出苗期>行粒数>行数;高产玉米自交系选育目标:尽量延长生育期,提高穗长及百粒重,其他性状适中,协调相关因素,提高产量。本试验利用大量有代表性的玉米自交系,明确了主要农艺性状对产量的贡献,为选育高产玉米自交系提供了理论参考依据。     

不同玉米种质材料植株与穗粒性状的灰色关联度分析

为了掌握生产上广泛使用的12个玉米单交种的主要农艺性状间的关系,对被测试材料的植株、穗粒、产量以及品质性状进行了灰色关联度分析。结果表明：与产量密切相关的植株与穗粒性状是出籽率、行粒数、穗粗、穗粒重、百粒重等,其关联度在0.4353~0.3327。与粗蛋白、粗脂肪、粗淀粉和赖氨酸含量等营养品质密切相关的植株与穗粒性状是出籽率、株高、穗长、轴粗、行粒数等,其关联度在0.5106~0.3929。综上所述,对于不同玉米种质材料进行遗传改良宜在保证正常生长的前提下,优先对出籽率、百粒重进行选择,还要注重对株高、穗长、轴粗、行粒数等性状的选择,进而提高育种效率。     

不同种质玉米自交系穗粒性状特征分析

玉米穗粒性状是决定产量的重要因素。为了明确不同种质玉米自交系的穗粒性状特征及对种质创新和高产育种提供参考,本研究以211个不同种质玉米自交系为材料,对穗长、穗粗、穗行数、行粒数、粒长、粒宽、粒厚、百粒重和籽粒密度9个穗粒性状进行统计和系统聚类分析。结果表明,供试玉米自交系间各穗粒性状均存在显著差异,除籽粒密度外均存在较大变异系数;采用欧氏距离法进行聚类分析将供试玉米自交系分为7个类群,穗长、穗粗、行粒数和粒长均以类群G6最高,粒宽和百粒重均以类群G5最高;郑单958和先玉335两大杂交种的4个亲本自交系各自所属类群相比,4个类群分别有单个或多个自交系多个性状较优,可以为育种工作中穗粒性状的改良提供依据。     

玉米产量的边际效应及与主要农艺性状的相关分析

研究玉米主要农艺性状与产量边际效应指数的相关性,为选育耐密植玉米品种提供参考。以品比试验中的10个玉米杂交组合为试验材料,对玉米产量边际效应曲线进行拟合,同时对产量边际效应指数与玉米主要农艺性状进行相关分析。结果表明,玉米产量的边际效应曲线符合方程Yi=e-ai,t值及Xc2值均未达到显著水平。玉米产量边际效应指数与穗长、穗粗、行粒数、出籽率等性状的边际效应指数相关性达到显著或极显著水平。穗行数边际效应指数与玉米产量边际效应指数的相关未达到显著水平。由此可见,在选育耐密植玉米品种时,应注重穗长、穗粗、行粒数、出籽率等性状的边际效应,可不考虑玉米穗行数的边际效应。     

不同干旱胁迫条件下我国玉米骨干自交系的抗旱性比较研究

以目前我国科研育种和生产中84份骨干自交系为材料,采用2种不同的干旱胁迫处理,依据成熟期产量和产量构成因素的表现剖析其抗旱性,发现我国玉米自交系存在着丰富多样的抗旱类型及抗旱丰产类型,它们是我国玉米抗旱育种的重要种质资源;抗旱性分析发现, 产量构成因素的抗旱性存在着较大差异,有些材料表现生育中、后期均抗旱,有些材料只在某一个生育时期表现较强的抗旱性;抗旱丰产性分析发现,产量构成因素的抗旱指数同样存在着较大的差异,有些材料穗粒数、百粒重抗旱指数均较高,有些材料穗粒数抗旱指数较高,还有些材料百粒重抗旱指数较高,表明不同的玉米能够以不同的途径实现抗旱丰产。     

玉米自交系植株性状状与单株产量相关性研究

为研究玉米自交系主要植株性状与单株产量的相关性,选择代表性的父本、母本自交系采取随机区组设计,测定其主要植株性状和单株产量。结果表明,穗行数、行粒数、穗位高、雄穗分支数、节间长与单株产量均显著正相关,其中,穗行数与单株产量的相关性最强,相关系数达0.8824。株高与节间长、穗位高（r=0.7372）、穗行数和雄穗分支数显著正相关。穗长与百粒重极显著正相关(r=0.6631)。出籽率与穗行数、行粒数极显著正相关。在自交系选育过程中,穗行数、行粒数等穗部性状直接影响自交系的单株产量,但株高等同样是自交系选育的关键性状,自交系选育要兼顾穗部性状和植株性状,以获得株型适中兼大穗型的高产品种。     

高产栽培条件下夏玉米穗部性状研究

本文采用灰色关联分析理论,对16个玉米杂交种穗部性状与产量的关系进行研究。结果表明,在高产栽培条件下,玉米产量与穗部性状的关联度排序为：粒数/m2＞千粒重＞穗粒数＞出籽率＞穗行数＞行粒数＞穗粗＞穗数/hm2＞穗长＞秃尖长。进一步分析表明与高产栽培条件相适应的杂交种是单位面积粒数较多、穗粒数和千粒重较高的中大穗耐密型玉米杂交种,出籽率较高;从玉米的形态性状来看,穗行数和穗粗对产量的影响大于行粒数和穗长对产量的影响。     

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.