Principal Response Curves analysis of polyphenol variation in resistant and susceptible cotton after infection by a root-knot nematode (RKN)

The root-knot nematode (RKN), Meloidogyne incognita, attacks cotton root system. This study aimed to compare the induction of phenolic compounds over time in two cotton genotypes, resistant (TX-25) and susceptible (FM966), by RKN. Chemical profiles of cotton roots were obtained by HPLC, NMR, and colorimetric methods at four different time intervals. The Principal Response Curves analysis, a time-dependent, multivariate method, showed consistent variability over time in the profile of phenolic compounds between treatments for both genotypes. The variables that most contributed to the divergence between damaged and undamaged cotton roots were dimethoxylated and non-methoxylated gossypols, total flavonoids, and total phenols.     

基于主成分分析的IPO发行成本影响因素研究

在对IPO发行成本及其构成进行界定的基础上，对IPO发行成本影响因素展开分析，并采用主成分分析方法从原始变量中提取5个主成分因子，实证检验各主成分因子对中国证券市场IPO直接发行成本、间接发行成本和发行总成本的影响。研究结果表明，IPO发行成本受到规模、上市前股权结构和企业财务风险的影响；发行定价机制的变动显著影响直接发行成本，与间接发行成本和总成本的关系则不明显。     

山区县耕地保护研究——以西林县为例

受自然条件的影响,山区的耕地保护工作难度加大。以广西西林县为例,运用主成分分析法分析发现,影响西林县耕地保护的主要因素是退耕还林,通过单对西林县标准分配面积的时空差异状况分析西林县耕地保护和生态保护存在的问题,提出了协调西林县耕地保护调控措施。     

SYSTEMATIC STUDY OF PHYSICAL AND MECHANICAL PROPERTIES OF IMPORTANT CHINESE WOODS

In this paper,the physical and mechanical properties of important Chinese woodswere studied by using the methods of variable analysis, regression analysis,correlation analysis,principle component analysis and so on systematically.The results showed synthetical characteristicof the physical and mechanical properties of Chinese woods.Some opinions of former authors wererevised and some new laws were discovered.That is helpful to study of the physical and mechanicalproperties of woods.     

安徽中籼稻主要产量因子结构研究

以安徽省2000—2005年的中籼稻区域试验和联合鉴定试验的424个品种(组合)为材料,对产量性状作了相关分析及主成份分析。分析结果表明:产量和每穗总粒数、每穗实粒数、结实率、千粒重均呈极显著正相关,与有效穗呈显著正相关,每穗总粒数、每穗实粒数、结实率与有效穗呈极显著负相关,千粒重与有效穗呈负相关。所以在中籼品种(组合)的高产育种中,应以选每穗总粒数、每穗实粒数为主攻目标,即要选育穗大粒多型品种,不必过于追求有效穗和千粒重。穗实粒数、产量与全生育期存在一定的正相关关系,但不显著,即生育期短的品种(组合)也可以实现高产。主成份分析也表明穗实粒数、穗总粒数是高产育种主攻的关键。并在分析基础上提出了中籼稻品种(组合)高产育种策略建议,为中籼新品种(组合)的选育提供参考。     

茎瘤芥(榨菜)数量性状遗传差异研究

对23份茎瘤芥品种资源的15个数量性状进行了主成分分析和聚类分析。结果表明:前5个主成分对变异的贡献率达85.32%,并筛选出6份综合性状表现优良的品种资源。23份品种资源被分为五类,配制组合宜在类间(D2>257.9)选择亲本。遗传差异的大小与品种的地理分布和熟性无直接联系。     

木薯主要农艺性状的遗传变异、相关性和主成分分析

对广西14个主要木薯品种的9个农艺性状进行了遗传变异分析、相关性分析和主成分分析。结果表明,块根长,块根鲜重、块根数的变异系数较大,分别为13.95%、11.33%、10.22%,块根干物质率和茎径的变异系数最小,分别为7.00%和6.57%;在相关性上,产量与块根数呈极显著的正相关,块根干物质率与块根淀粉含量呈极显著的正相关;主成分分析结果表明,前4个主成分对变异的贡献率达85.69%。在性状选择上,首先对变异大的性状进行选择是非常重要的。在品种选择时,应注意选择产量和淀粉含量均高的品种。     

Diversity in White Lupin (<Emphasis Type="Italic">Lupinus albus</Emphasis> L.) Landraces from Northwest Iberianplateau

All the accessions (35) of white lupin (Lupinus albus L.) landraces collected from northwest Iberian plateau and maintained at the Spanish germplasm collection (CRF of INIA), were studied with the general objective of assessing the biodiversity of these landraces and to ascertain their value as genetic resources for the development of germplasm adapted to the areas where they were collected with long and chilly winters. The characterization study comprised 51 qualitative and 50 quantitative characters. Quantitative parameters were analyzed by Principal Components Analysis (PCA). The 2-dimensional plot (49.3% of cumulative variability) formed a main group of accessions and 4 outliers (#1, #9, #27 and #28) separated in the first PC. The characters with a higher contribution to the first PC were inflorescence length, leaf petiole length and leaf central foliole area. The presence of alkaloids, the percentage of plants killed by soil borne fungal diseases, the phenology, the yield per plant and yield components were also assessed. Twenty six accessions (the main group in the PCA plot) showed high homogeneity, with the following highlights: bitterness, indeterminate growth habit, early ripeness and spring sowing with the exception of #18, in which seeding date is unknown and it had a later phenology. By contrast accessions #9 and #27 were bitter of autumn sowing with determinate growing habit and they had the longest values of primary inflorescence length and a later phenology when they were sown in spring. Average values for yield and yield components showed a broad range of variation between accessions. The main yield component was the number of pods per plant. Accession #22 had the highest mean seed mass, although this had not significant influence in yield. Accession #17 showed the highest yield and #1 the lowest. This last also had the lowest values of inflorescence length, leaf petiole length and leaf central foliole area. No significant differences of resistance to soil-borne fungi were found between accessions. The year had a significant effect in the phenology, yield and yield components except for number of seeds per pod. The studied material might be of interest for the development of spring sowing germplasm adapted to north Iberian peninsula.     

基于PCA的福建省顺昌县森林健康评价

以福建省顺昌县的杉木纯林、毛竹纯林、杉木马尾松混交林、杉木阔叶混交林、阔叶林等5块样地为对象,从结构性、功能性和抗干扰性等3个方面出发,筛选出15个指标,并利用主成分分析（PCA）实现了研究区森林健康评价。结果显示：福建省顺昌县杉木纯林、毛竹纯林、杉木马尾松混交林、杉木阔叶混交林、阔叶林等5块样地的森林健康综合指数值依次为-0．27、-0．25、0．35、0．53和-0．01,从优到次的排名为：杉木阔叶混交林、杉木马尾松混交林、阔叶林、毛竹纯林、杉木纯林。     

Geographic Pattern of Genetic Diversity Among 43 Ethiopian Mustard(Brassica carinata A. Braun) Accessions as Revealed by RAPD Analysis

As an oilseed crop, the cultivation of Ethiopian mustard (Brassica carinata) is restricted only to Ethiopia. Even though geographic diversity is a potent source of allelic diversity, the extent of genetic diversity among germplasm material of Ethiopian mustard from different countries has not been assessed. Forty-three accessions, comprising 29 accessions from eight different geographic regions of Ethiopia and 14 exotic accessions from Australia, Pakistan, Spain, and Zambia were analysed for their genetic diversity using random amplified polymorphic DNA (RAPD) technique. A set of 50 primers yielded a total of 275 polymorphic bands allowing an unequivocal separation of every Ethiopian mustard accession. The usefulness of the 50 RAPD primers in measuring heterozygousity and distinguishing accessions was variable such that polymorphic information content (PIC) varied from 0.05 to 0.40, band informativeness (BI) from 0.05 to 0.65 and primer resolving power (RP) from 0.15 to 6.83. Jaccard's similarity coefficients ranged from 0.44 to 0.87 indicating the presence of a high level of genetic diversity. On the average, Australian and Ethiopian accessions were the most similar while, Spanish and Zambian accessions were the most distant ones. Cluster analysis grouped the 43 accessions into four groups, which has quite a high fit (r = 0.80) to the original similarity matrix. With no prior molecular information, the RAPD technique detected large genetic diversity among the 43 accessions from five different countries and their grouping by dendrogram and principal coordinate analysis (PCoA) was inclined towards geographic differentiation of RAPD markers. Conversely, RAPD differentiation along geographic origin was not apparent within the Ethiopian accessions.