温敏核不育水稻的遗传与稳定性

 以安农S-1、衡农S-1和W6154S为材料，研究了温敏核不育水稻的遗传与稳定性。三个不育系各世代的育性转换特性是稳定的，不受年份、地点的影响；三个不育系的育性基因可能是非等位的，安农S-1、衡农S-1的育性由一对隐性基因控制，W6154S的遗传模式尚难确定；W6154S的群体育性不太整齐，单株、单穗以及颖花之间的育性有所差异，安农S-l和W6154S的育性基因表达受遗传背景的影响，W6154S的后代不育株有育性分离。     

Pathogenic and Genetic Diversity of Magneporthe oryzae Populations from Sri Lanka

The present study was undertaken to determine the pathogenic and the genetic diversity of the isolates of M.oryzae collected from the wet,intermediate and dry zones of Sri Lanka with a view to develop rice varieties conferring durable resistance to rice blast.No significant morphological or growth variations existed amongst the isolates studied.The genetic diversity of isolates determined by carrying out Pot2 transposable element based on repetitive-PCR revealed that the majority of isolates (92%) clustered into a single group with 45.4% similarity.The existence of nine pathotypes was identified by observing the reaction type of isolates on 16 different rice lines.Pathotype 1 which was distributed in all zones affected only one differential line.Pathotype 2 which was able to infect six lines was restricted only to the dry zone of Sri Lanka.Of the 16 rice lines,seven lines,K3 (Pik-h),C101A51 (Piz5),K1 (Pita),C105TTP2L9 (Pita),K59 (Pit),Shin (Pish) and WHD-1S-75-1-127 (Pi9) had highly effective blast resistance.None of the isolates of the fungus showed any virulence against the seven lines.These seven blast resistant lines can be used in the breeding programmes in Sri Lanka for development of lines conferring durable resistance to rice blast.     

杂交水稻保持系垩白粒率遗传研究

对垩白率不同的5个保持系正反交形成的10对F1、 F′1垩白粒率进行测定和分析,结果发现,垩白粒率在遗传中受到主效基因控制,垩白粒率高对垩白粒率低表现显性或部分显性.对于两个亲本而言,其正交组合的垩白粒率与反交组合垩白粒率有明显差异,以低垩白粒率亲本作母本、高垩白粒率亲本作父本配制的F1 组合的垩白粒率要低于其反交组合米粒的垩白粒率.因此,在优质杂交稻育种中,宜选用垩白粒率低的亲本为母本进行杂交或配组.     

吉林省稻穗瘟药剂防治指标的初步研究

文中确定了吉林省稻穗瘟病的经济损失允许水平:水稻黄熟期穗瘟发病率8～10％或穗瘟病情指数3～4。又根据吉林省有代表性的八个试验点五年的稻叶、穗瘟系统调查资料分析认为，决定吉林省生产中稻穗瘟最终病情的因素有三个:一是田间叶瘟基数;二是抽穗扬花期的气象条件;三是由当地生态栽培条件、水稻品种及稻瘟病菌生理小种群体共同决定的稻株抗病力。在此基础上提出吉林省稻穗瘟药剂防治指标。     

High‐Growth Firms in the Southern U.S.: Where is the Growth?

Policymakers across the Southern U.S. have directed considerable attention to regional economic development plans, with mixed results. Questions remain over what types of industries, firms, and/or policies can drive long‐range growth. Over the past two decades, researchers have started to focus on high‐growth firms (HGFs) due to their potential innovation spillovers and job creation prospects, both of which drive further economic development. Employing databases from the Inc. 500, this study explores the dynamics of HGFs within Southern and comparative contexts. The first goal of this paper is to explore Southern HGF activity in comparison with the U.S. at‐large. The second is to examine the geographical characteristics of HGFs within the South, which will include an exploration of locations, industrial mix, and the factors that could encourage HGF development and agglomeration. This paper will also analyze the longer‐term ownership and acquisition patterns of HGFs across the South. Are such firms remaining embedded in the South or moving elsewhere through mergers or acquisitions? The paper concludes with a discussion of the impacts of HGFs on regional economic development and moreover, whether existing policies are conducive to these firms.     

Circulating Metabolic Hormones During the Peripubertal Period and Their Association with Testicular Development in Bulls

The objective of the present study was to characterize changes in serum metabolic hormones concentrations from 20 weeks before to 20 weeks post-puberty in bulls and to investigate the associations of metabolic hormones concentrations with testicular development. Leptin concentrations increased from 16 weeks before puberty to 8 weeks post-puberty and insulin concentrations increased from puberty to 8 weeks post-puberty. Growth hormone concentrations decreased after 4 weeks post-puberty, whereas IGF-I concentrations increased from 8 weeks before puberty to 8 weeks post-puberty. During this period, testicular growth was accelerated and testosterone secretion increased substantially, without any significant changes in gonadotropin secretion. Monthly circulating concentrations of leptin, IGF-I and insulin accounted for 63% of the variation in scrotal circumference and 59% of the variation in paired testes volume. In conclusion, the secretion of metabolic hormones was not associated with changes in gonadotropins concentrations. Furthermore, the associations of leptin, IGF-I and insulin concentrations with testes size indicated that these hormones might be involved in a gonadotropin-independent mechanism regulating the testicular development in peripubertal bulls.     

Bovine monoclonal antibodies specific for bovine herpesvirus-1 glycoprotein gIII

Spleen cells from a calf immunized with bovine herpesvirus-1 (BHV-1) were fused with the nonsecreting murine cell line SP2/0. Several bovine-murine hybridomas secreting bovine immunoglobulins were stabilized. Of these, 9 hybridomas secreted bovine monoclonal antibodies that specifically bound to BHV-1 in a radioimmunoassay. Two of these monoclonal antibodies reacted specifically with BHV-1 in an indirect fluorescent antibody test and immunoprecipitated a BHV-1 glycoprotein with molecular mass of 97 kilodaltons.     

粳型陆稻恢复系资源的筛选及其利用研究

对不同粳稻不育系与146个粳型陆稻品种测交所得21 7个组合的结实率观测结果表明,测交组合的平均结实率为36.3%,其中24个组合(占11.1%) 的结实率＞70%,说明与普通粳稻不同,粳型陆稻品种中存在丰富的恢复系资源.与不同地区的陆稻品种测交,不同质源的不育系的可恢性有一定差别.对7个组合的产量、8个组合的米质(糙米率和垩白粒率)与其相应的父本进行比较的结果表明,测交组合产量优势明显,且米质也得到显著改善.另对2个测交组合进行旱作种植,不仅比大面积应用的杂交粳稻黎优5 7大幅增产(增幅达93.2%),而且比陆稻父本也增产;在旱种和水田条件下产量接近黎优 57的水平.如对亲本进一步筛选和改良,有望育成水旱兼用、在不同栽培条件下均能显著增产的水陆稻杂交种,在旱涝并存地区具有广阔的应用前景.