松属线粒体基因序列变异研究

本研究利用ＰＣＲ和ＰＣＲ产物直接序列分析技术,获得了分属于松属（Ｐｉｎｕｓ）两个亚属Ｐｉｎｕｓ和Ｓｔｒｏｂｕｓ１２个松树种ｃｏｘＩ、ａｔｐ６和ｏｒｆ２５三个线粒体基因ＤＮＡ片段的序列。发现ｃｏｘＩ基因的ＤＮＡ序列在属内没有任何变异,但ａｔｐ６和ｏｒｆ２５在两个亚属间和亚属内出现了较多的碱基置换。这说明尽管裸子植物线粒体基因有较多的ＲＮＡ编辑（ＲＮＡｅｄｉｔｉｎｇ）存在,可促进ＤＮＡ序列的变异,但促进程度因不同基因而异。依据ａｔｐ６和ｏｒｆ２５所做的系统进化树不仅与分类结果一致,而且进一步表明了亚属内种间的亲缘关系。尽管线粒体基因序列变异比叶绿体和核ＤＮＡ变异小,线粒体基因编码序列变异仍适于研究裸子植物亚属甚至组间的系统进化关系。     

麻疯树种质资源nrDNA ITS 序列的遗传分析

通过PCR 扩增并测序分析了18 份不同地理来源的麻疯树种质资源的nrDNA ITS 序列,为今后麻疯树 优良种源的选择和开发利用提供理论依据。测序结果表明,麻疯树各种质资源的ITS 序列为648~649 bp,G+C 含量 在64.10%~64.71%之间;各资源的遗传距离为0.000~0.069,平均值仅为0.010。进化树分析表明,18 个麻疯树种质资 源基本上聚为1 类,没有得到具有较高支持率的分支,且各资源的遗传差异系数极低。本研究结果再次证实麻疯树 种质资源的遗传基础偏窄,遗传变异小。     

Two-component method for crossing self-fertilized crops

Summary The paper presents the method of choosing parents for simple and multiple crossings formularizing the well-known principles i) effective performance of breeding traits in hybrid population and ii) genetic divergence between parents; an original procedure of the integral performance estimation of hybrid population taking into consideration the specific features of a breeding program; an estimation of divergence between parents by way of computing the parentage coefficients. It gives a substantiated computation of the objective heuristic function in the process of assessing various combinations of crossing on the basis of both estimations, the said function offering a quantitative evaluation of the relative perspective efficiency of the hybrid combinations before crossing.     

联苯菊酯对棉叶气孔开张度的影响

采用田间喷施和室内显微镜检方法 ,研究了棉株叶片气孔日动态变化及联苯菊酯在新疆塔里木地区气候环境条件下对棉株叶片的气孔影响。结果证明 ,棉株叶片气孔的开张度在一天中随时间呈“双峰”型变化趋势 ,喷施农药的叶片气孔的开张度也呈“双峰”型变化 ,但与未喷药的棉花叶片有明显差异 ,表明农药可能影响棉株的生理代谢过程。     

带状电子束发散因素的分析

本文分析了带状电子束发散因素,从而有助于估算电子束流密度,为设计符合要求的、用于大功率二氧化碳激光器的电子枪提供了依据.     

甜玉米距离分析与杂种优势的研究

根据 70个甜玉米自交系数量性状的表现计算了遗传距离 ,又计算了由其中 4 2个自交系间随机组配的 89个杂交组合F1 代小区产量、含糖量的对照优势。其结果表明 :F1 代产量的对照优势与其双亲之间的遗传距离呈显著的二次曲线关系 ,而F1 代含糖量的对照优势与其双亲之间遗传距离无确定性关系。因此 ,可以根据遗传距离预测杂种F1 代产量的杂种优势 ,而聚类分析对于甜玉米产量杂种优势的预测和亲本选配没有指导意义。     

Segmentation of Color Image Based on Feature Divergence and Fuzzy Theory

In order to improve general adaptive capability of algorithm,the new color image segmentation algorithm based on feature divergence and fuzzy theory(FDCIS) is proposed.The algorithm introduces feature divergence and fuzzy dissimilarity function into calculation in order to measure the dissimilarity of feature vector,clusters data by means of feature divergence,and accomplishes the merge of image region.The experimental results demonstrate that the color image segmentation result of the proposed approach reduce calculation on large sample of color image,simply and effectively solve over-segmentation of color image,avoid the dependence of the algorithm on initial condition,and hold favorable consistency in terms of human perception.     

Heterosis in relation to genetic divergence and specific combining ability in groundnut (Arachis hypogaea L.)

Summary The frequency and magnitude of heterosis were examined in relation to genetic divergence among parents in two diallel cross experiments in groundnut. The parents were grouped into clusters based on their diver-gence. The range, mean and standard deviation of the intra-and inter-cluster divergence were used to define four divergence classes. The frequency of heterotic crosses and the magnitude of heterosis for yield and its components were found to be higher in crosses between the parents in intermediate divergence classes than extreme ones. The results agreed well with the overall status of the specific combining ability of these crosses.     

Phenotypic divergence for morphological and yield-related traits among landrace genotypes of durum wheat from Jordan

Summary Landrace genotypes of durum wheat, from 10 districts in Jordan, have been evaluated for 18 morphological and yield related traits. Results of multivariate analysis, including analysis of variance, cluster analysis and canonical discriminant analysis, indicate that the magnitude of phenotypic divergence in these landrace genotypes is large, especially when compared with a world collection of durum wheat. These results provide an experimental evidence for phenotypic differentiation as a result of variation in altitude and long-term average rainfall of collection sites, but not on the basis of district of collection. R²-values for fit to least squares model ranged from 67.0–78.0%, and from 18.5–30.0%, for the first and second cases, respectively. Landrace genotypes from different districts formed 5 clusters on the basis of altitude and long-term average rainfall of collection site. Three canonical factors accounted for 92% of total variance in these clusters. The first canonical factor accounted for 57% of total variance and was mainly correlated with spike length, awn length and spikelets/spike. The second canonical factor accounted for 22% of total variance and was positively correlated with peduncle length, seed weight per plant, kernel weight and ratio of peduncle length to plant height. However, it was negatively correlated with awn length. The phenotypic diversity found in these landrace genotypes could help identify genetically different genotypes for durum wheat improvement.     

河北省野生大豆天然群体中胰蛋白酶抑制剂蛋白的多态性

 在河北省搜集了东北部山区、东北部平原、白洋淀湖泊区、西南丘陵山区等 18个天然野生大豆群体的 4 6 1份植株种子样本 ,调查其Kunitz型胰蛋白酶抑制剂蛋白 (KTI)的形态及蛋白位点在野生大豆天然个体群体及地理的频率变化。结果显示超过 5 0 %个体群体的KTI位点是多态的 ,18个天然个体群体中 12个群体形态是由Tia和Tib构成的混合群体。这次测定的河北野生大豆中没有发现Tic形态存在。在 12个混合群体中 ,4个群体发现存在Tia/Tib杂合种子 ,约占调查群体的 2 2 % ,在野生大豆总群体中至少有 1%的异交率。河北天然野生大豆Tia基因频率约占 85 % ,Tib约 15 %。地理上 ,东北部山区和平原生态区比南部的白洋淀和西南丘陵山地生态区有较高的Tib频率 ,无论在南部或北部 ,山区生态区Tib频率高于平原生态区 ,同时山区生态区内的个体群体间的基因频率差异变化程度高于平原群体间的变化 ;个体群体的基因频率没有看到与地理距离有相关性。白洋淀湖泊生态区虽然有河北最大的野生群落 ,但是KTI位点是Tia单态的 ,湖内和湖外群体KTI位点是一致的单态性 ,暗示白洋淀区域野生群体间受湖水流动的影响 ,使Tia型种子在群体传播形成一个单态优势型 ,也许这个区域的野生大豆遗传背景较其它地区群体狭窄。在这个研究中 ,我们还首