THE INDUSTRIAL ORGANIZATIONS AND THE L-S-BUSINESS STRATEGIES

This papar presents an evolution model in business behaviors-the L-S Business Strategies,gives some examples and predictions which support these strategies,and analyzes the relationship between the industrial organizations in China and the L-S Business strategies.     

玉米人工合成群体产量相关性状选择潜势及杂种优势模式分析

采用NCⅡ遗传交配设计 ,以分属于不同杂种优势群的 6个自交系做测验种 ,与 6个合成群体组配成 36个组合。结果表明 :单株产量的GCA以LBM最高 ,其次为WBM ,从株型、穗型性状的SCA分析合成群体与自交系组成了 9个优良杂种优势模式。单株产量最高的组合为HZ85×WBM ,其均值为 10 8 75g。通过对优良杂优模式内的变异参数估计 ,在群体内有丰富的变异个体 ,具有很强的选择潜势。组合内个体产量分布以及出现的频率对选系和轮回选择具有明确的指导意义。人工合成群体具有丰富的遗传变异 ,分属于不同的杂种优势类群 ,具有多元种质的特性。作为选系和轮回选择群体 ,具有明显的选择潜势     

水科学中应用数理统计方法应注意

对回归方程误差的影响因素进行了分析，导出了回归方程的均方误差与其影响因素之间的关系式。分析表明，复相关系数(或相关系数)一定时，倚变量的变差系数越大，回归方程的均方误差就越大；回归分析时，应对回归方程的误差进行分析。对于样本均值估计总体均值，给出了基于误差限制的样本容量的计算式。研究表明，应考虑样本变差系数对估计精度的影响。     

大理州“红阳”猕猴桃真菌性枝干的发生与病原鉴定

以大理州"红阳"猕猴桃枝干为试材,采用田间调查法调查病原菌对其危害状况,对采集的10份病样采用常规组织分离法分离病原,单孢纯化法获得病原菌,采用形态和分子法鉴定病原种类,以期明确大理州"红阳"猕猴桃枝干病害的发生状况及危害病原。结果表明:大理州"红阳"猕猴桃枝干病害发生严重,病株率高达69.6%,5个采样点共分离得到15个菌株,其中以链格孢菌(Alternaria alternata)、厚坦镰刀菌(Fusarium chlamydosporum)、小新壳梭孢菌(Neofusicoccum parvum)和间座壳属中一种(Diaporthe bohemiae)共4类病原菌出现频率最高,是优势种,分离率分别为55.6%、52.4%、49.8%和50.1%。利用柯赫氏法则对分离所得的所有菌株进行致病性测定,证实了优势菌株对猕猴桃茎杆的致病性,进一步明确了引起大理州猕猴桃茎杆的病原真菌。     

保种群体遗传结构变化的模拟研究

本文运用电子计算机模拟的方法,分析了影响畜禽保种的主要因素,并通过不同参数组合(包括起始基因频率、群体有效含量和世代数等)的模拟试验得出三个主要结论: 1 在有性繁殖的有限群体中,原封不动地保存群体基因库中的每个基因(包括频率很低的基因)是根本不可能的。 2 在完全实行随机交配的情况下,长期保存频率较高的基因也需要相当大的群体才有可能。 3 频率较高基因的保存也不能单纯依靠群体大小,还需借助于选择。只有这样才能在小群体内长期保存频率较高的基因。     

籼稻品种对三个白叶枯病菌系的抗性遗传分析

分析和研究了全生育期表现抗病的5个籼稻品种二九丰、三黄占2号、川植5号、扬稻1号和83007对3个水稻白叶枯病菌系HB84-17、PXO16和T7174的抗性遗传,对这5个抗病品种分别与感病品种沈农1033或金刚30杂交的F_1、F_2和B_1F_1群体植株对供试3个菌系的抗性反应和分离世代植株抗感分离比例的分析结果表明:供试的5个籼稻抗病品种对菌系HB84-17和PXO61的抗性均由一对显性基因控制,对菌系T7174的抗性均由二对独立遗传的显性基因控制,其中一对能控制对这3个菌系的抗性,另一对只控制对菌系T7174的抗性而对菌系HB84-17和PXO61表现为感病。     

双向链表人口迁移算法

最短路径搜索是路径分析中的热点问题.将双向链表和人口迁移算法的智能进化体制相结合,提出一种新的启发式智能仿生优化算法——双向链表人口迁移算法,并用于求解最短路径问题.仿真实验结果表明：双向链表人口迁移算法求解最短路径搜索问题是可行、有效的.     

TILLING技术及其在农作物中的应用现状

TILLING技术是一种全新的反向遗传学研究方法。文章简要介绍了TILLING技术的原理、操作流程、技术要点及其特点,并总结了TILLING技术在麦类、玉米及水稻研究中的应用现状。     

Census and effective population sizes of white‐spotted charr (Salvelinus leucomaenis) in a fragmented landscape

Several habitat models have been proposed to predict population size for stream fishes and to guide habitat assessment and monitoring techniques. However, most models do not incorporate the potential advantage of molecular genetic markers. We conducted a field survey and microsatellite DNA analyses to quantify the relationships among genetic diversity, census/effective population size and habitat variables in fragmented populations of white‐spotted charr (Salvelinus leucomaenis). The census population size significantly increased with the stream length, the number of pools and a pool‐riffle sequence index, a proxy for channel‐unit habitat type complexity within reaches. Population density was correlated with the pool‐riffle sequence index only. Genetic diversity and effective population size were not correlated with the habitat variables or census population size. There was a lack of isolation‐by‐distance population structure in the studied populations. Our results suggest that stream length and the number of pools within reaches associated with habitat complexity are the habitat variables that explain the majority of variation in population size of white‐spotted charr. Our findings provide further evidence that census population size per se is a poor indicator of the inclusive genetic diversity within populations in a fragmented landscape.     

Invasive black spiny‐tailed iguanas (Ctenosaura similis) on Gasparilla Island,Florida, USA

The native range of Ctenosaura similis extends from southern Mexico through Panama. From an initial introduction of 3 animals in 1979, the species now numbers in the thousands on Gasparilla Island in southwest Florida. In response to complaints of property damage from residents and threats to native species, local officials and the US Department of Agriculture Wildlife Services began a removal program in 2008. Through 2011, trappers removed 9467 ctenosaurs. The number removed declined from 32 iguanas/day in 2008 to 1.9 iguanas/day in 2011 despite no easing of the control effort. We necropsied 2757 ctenosaurs to document aspects of their natural history. Females outnumbered males overall, although the largest size class (>300 mm snout–vent length) included 32 males and just 2 females. Reproduction was seasonal. We found oviducal eggs in females from early Apr to early Jun, approximately 2 months later than C. similis in its native range. We trapped hatchlings from late Jul to early Oct coincident with the summer rainy season. Clutch size increased with female body size, with 62 being the largest clutch size recorded. In general, the biology of the invasive population on Gasparilla Island resembles native C. similis populations in Central America, except for the lack of large individuals. We suggest that shorter day length and colder temperatures create environmental conditions that are suboptimal for individual growth compared to those in the native range.