水稻细菌性条斑病抗性QTL qBlsr5a的精细定位

分别以高抗细菌性条斑病的品种Acc8558和高感的品种H359为供体和受体亲本, 通过回交和分子标记辅助选择, 育成了只渗入5号染色体短臂上单个供体亲本细条病抗性QTL(qBlsr5a)的近等基因系H359-BLSR5a。将该近等基因系与H359杂交, 建立了一个大的F₂群体。采用选择极端表型个体并验证其后代(F_2:3)株系的方法, 在F₂群体中鉴定出目标QTL为抗病纯合基因型的个体。通过对这些个体进行分子标记基因型检测和连锁分析, 将qBlsr5a定位在SSR标记RM153和RM159之间, 大约2.4 cM或290 kb的范围内。     

利用生物信息学和qRT-PCR分析鉴定水稻细菌性条斑病QTL qBlsr5a的候选基因

细菌性条斑病(简称细条病)是水稻的主要病害之一。前期研究已将细条病抗性QTL qBlsr5a精细定位在5号染色体上一个大约300kb的区间内。为了寻找该QTL的候选基因,本研究利用生物信息学方法对该区间进行分析,筛选出10个与抗病相关的注释基因。然后以感病品种H359及其抗病近等基因系H359-BLSR5A为材料,对细条病菌接种后这10个基因的表达动态进行qRT-PCR分析。结果表明,2个基因在抗、感材料中几乎没有检测到表达产物;7个基因对病原菌侵染没有明显的响应;1个基因(LOC_Os05g-01700)在病原菌侵染后表达量发生变化且在抗、感材料间存在显著差异。因此推测,该基因是qBlsr5a的一个重要的候选基因。     

水稻显性早熟基因Ehd的SSR标记定位

以籼稻品种广陆矮4和粳稻品种台中65为亲本构建高世代回交分离群体,选用分布于水稻全基因组的145个SSR标记对亲本及抽穗期早熟基因进行分析.结果表明,114个标记在亲本间具有多态性,多态率78.6%;在BC3F1群体中,检测到10个标记的基因型来源于供体亲本广陆矮4号;在BC3F2定位群体中,早熟植株数与晚熟植株数的分离比例为3:1,早熟植株平均比晚熟植株提早抽穗21 d;通过SSR标记与抽穗期共分离分析将显性早熟基因Ehd界定在分子标记RM271和RM258之间;Ehd与标记RM184和RM271紧密连锁,遗传距离分别为2.6 cM和2.1 cM,此结果为该基因分子标记辅助选择奠定了基础.     

抗水稻纹枯病qSB-9^Tq基因效应及作用方式分析

水稻第9染色体上存在1个抗纹枯病QTL,被命名为qSB-9,水稻品种特青在该QTL上携带抗性等位基因qSB-9Tq,而Lemont携带相对感病等位基因qSB-9Le.为精确地评价qSB-9Tq的抗病效应,分析其作用方式,利用分子标记进行前景选择和背景选择,从轮回亲本Lemont与特青回交后代群体中筛选到1个目标单株.连续3年对该单株的扩繁后代(BC6F2)及随后获得的近等基因系采用嵌入法进行接种鉴定试验.田间试验采取2种不同的设计.第一种是完全随机试验,即从BC6F2分离群体中筛选出目标区间为qSB-9TqTq纯合型、qSB-9LeLe纯合型和qSB-9TqLe杂合型个体,并对3种基因型个体间的病级平均数差异进行统计分析.第二种设计为随机区组设计,即在BC6F3和BC6F4代,分别对上述3种基因型的近等基因系群体,按3次重复的随机区组设计进行移栽和接种鉴定试验.结果表明,3年的试验结果表现出一致的趋势,即qSB-9Tq存在于分子标记RM242～Y92.5之间,可减轻病级1.0级(O～9级病情分级系统)左右,且其抗性表现为几乎完全的显性特征.本研究的结果为qSB-9Tq的精细定位和育种利用奠定了基础.     

采用SSR标记辅助选育具有Xa22（t）的云南高原粳稻新种质

以高原粳稻新品种滇粳优1号为轮回亲本，携带Xa22（t）基因的云南地方稻种扎昌龙为供体亲本，回交后代BC3F1290个株行和BC3F2290个株行为供试材料，采用与Xa22（t）紧密连锁标记RM224及其它1l对SSR标记进行辅助选择。290株BC3F1个体在RM224位点上杂合基因型个体的比率为21．04％；其它11对SSR标记位点的轮回亲本纯合基因型个体比率平均为93．07％，但不同染色体标记位点上纯合基因型的比率不同。用云南高原粳稻上的白叶枯病优势菌株YH24对亲本、BC3F1单株和BC3F2株行接种鉴定，     

水稻抗性淀粉相关SSR标记的初步研究

将高抗性淀粉（resistantstarch,RS）突变体RS111与中等和低直链淀粉含量水稻品种II-32B和宜香B杂交,构建F2群体,发现位于第8染色体上的RM72和RM547和位于第6染色体上的RM217和RM225与RS相关。在杂交组合II-32/RS111的F2群体中,RM72和RM547与抗性淀粉和直链淀粉含量关系密切,出现了低亲本、杂合及高亲本3种基因型,且不同基因型间RS和AAC达1%显差异;在杂交组合宜香B/RS111的F2群体中,按标记RM217和RM225基因型可区分低与中高RS含量,其中RM225杂合型和高亲本类型间RS含量达5%差异水平。     

水稻籼粳杂交F2群体中分子标记的异常分离及染色体定位

本研究利用粳稻品种石狩白毛和籼稻品种明恢63杂交的F2分离群体共116株，构建了含88个共显性分子标记的连锁图谱，覆盖了水稻(Oryza satiwa L．)基因组1406cM。分析了这些共显性标记在F2群体中的分离情况。结果表明，有27个标记(30．7％)的分离显著或极显著的偏离了预期的孟德尔比例(1：2：1)而表现为异常分离，同时还发现了6个异常分离的热点，即第1染色体上RM302——RM212，第3染色体上RMl43——RM85，第6染色体上RM540——RM276，第7染色体上PAl—A5261．和RM432——RM455，第12染色体上RM519——RM235。偏离分别指向两种亲本基因型。说明相关的异常分离因子以不同的方式控制雌雄配子的传递比例。     

利用4个姊妹近等基因系群体定位水稻粒重和粒形QTL

粒重是决定水稻产量的三要素之一。利用世界上粒重最大的品种之一SLG-1(供体亲本)与小粒品种日本晴(Nipponbare,轮回亲本)杂交,在各回交世代选择粒重较大单株与日本晴回交,构建水稻粒重和粒形的姊妹近等基因系(SNILs)。对获得的73株BC4F1单株进行粒重频率分布统计,选择粒重频率分布在4个峰值处的代表性单株,自交获得4个BC4F2SNILs群体。利用BSA法(分离群体分组混合分析法),从均匀分布在水稻染色体上的1513对SSR标记中筛选出与粒重和粒形相关的多态性标记19对,以LOD≥2.5作为选择阈值,对粒重、粒长、粒宽和粒厚进行QTL扫描,共检测到6个区域的12个QTL,贡献率从7.22%到53.38%。这些QTL所在区域包含已克隆的粒长GS3和粒宽GW2,也包含没有精细定位的第2染色体的RM6318～RM1367、第3染色体的RM5477～RM6417和第6染色体的RM3370～RM1161等3个区域控制粒重和粒形的5个QTL。其中第3染色体上RM5477～RM6417区间存在粒形贡献率较大的新的QTL。构建含有这些粒重QTL的姊妹近等基因系,为进一步精细定位或克隆新的粒重或粒形QTL奠定了基础。     

水稻单片段替换系群体的建立及QTL定位

水稻中许多重要的农艺性状属数量性状，由多基因(QTL)控制。研究QTL的遗传特性和遗传效应对于培育高产和稳产的水稻品种具有十分重要的意义。本研究以6个优良的品种为供体亲本，以华粳籼74为轮回亲本，通过微卫星标记辅助回交选择培育了一批单片段替换系，随后利用所培育的单片段替换系进行了QTL分析和基因定位。主要结果有：1、利用258个微卫星标记对6个供体亲本和轮回亲本间的多态性进行了筛选。6个供体亲本与轮回亲本间的多态率在32．98％至60．78％之间，平均47．81％，粳型供体亲本比籼型供体亲本的多态性要高。2、随着回交代数的增加，植株所含的替换片段数逐渐减少。在BC2F1、BC3F1、BC3F2和BC3F3代，平均每个植株携带有12．50、5．98、1．69和1．46个替换片段。替换片段的平均长度也随回交和自交代数的增加而逐渐变短。在BC2F1、BC3F1、BC3F2和BC3F3代，替换片段的平均长度分别为25．43cM、22．38cM、20．78cM和18．15cM.回交世代替换片段变短的速率(11．99％)比自交世代变短速率(7．15％)要快。在BC2F1、BC3Fl、BC3F2和BC3F3代，轮回亲本基因组的恢复率分别为82．24％、92．55％、98．04％j阳98．52％。3、在BC3F2和BC3F3代，共选育出111个单片段替换系，其中独一无二的单片段替换系共42个。BC3F2代替换系中替换片段的估算长度在2．00cM到64．80cM之间，平均为21．75cM，而BC3F3代中替换片段的估算长度在6．05cM到48．90cM之间，平均为20．95cMc，12条染色体中仅第11染色体没有选择到单片段替换系。所选育的单片段替换系中替换片段的总长为2367．50cM，基因组的覆盖长度为704．50cM，覆盖率为39．25％。4、在52个单片段替换系的22个性状中共鉴定出了234个QTL。每个性状鉴定出的QTL数在3到19个之间，平均4．50个。每个替换系鉴定出的QTL在2到15个之间，平均10．64个。QTL加性效应的大小因性状和替换系不同而不同，低至-0．02(0．79％)的加性效应(如谷粒宽度)均能检测到。在RM237．RM322、RM225和RM481标记附近的各种性状中同时检测到了增效和减效的QTL。5、通过染色体替换作图，对7个单片段替换系中16个性状的QTL进行了定位。利用携带有相同替换片段的替换系进行QTL位置的确定。6、通过分析复杂性状的加性效应，对影响植高、每穗粒数和粒型的相关性状进行了分析，分析QTL之间的相关性。7、对控制抽穗期、稃尖颜色、植株高度和粒型的基因进行了定位。抽穗期基因Hd-8表现为单基因显性遗传，定位于第8染色体上，与PSMl55紧密连锁。紫色稃尖基因Pa-6表现为单基因显性遗传，定位于第6染色体上，与RM253紧密连锁。株高基因Ph-1-3定位于第1染色体上，与PSM331紧密连锁。粒型基因Rlw-8-2为首次报道，定位于第8染色体的末端，与RM447紧密连锁，长粒表现为单基因隐性遗传。本研究通过分子标记辅助选择培育了一批单片段替换系，并成功地对这批材料进行了QTL分析和基因定位，从而证实了在水稻中通过微卫星标记辅助回交选育单片段替换系和进行QTL分析的可行性。     

采用SSR标记辅助选育具有Xa22(t)的云南高原粳稻新种质

以高原粳稻新品种滇粳优1号为轮回亲本,携带Xa22(t)基因的云南地方稻种扎昌龙为供体亲本,回交后代BC3F1290株和BC3F2290个株行为供试材料,采用与Xa22(t)紧密连锁标记RM224及其它11对SSR．标记进行辅助选择。290株BC3F1个体在RM224位点上杂合基因型个体的比率为21．04％;其它11对SSR．标记位点的轮回亲本纯合基因型个体比率平均为93．07％,但不同染色体标记位点上纯合基因型的比率不同。用云南高原粳稻上的白叶枯病优势菌株YH24对亲本、BC3F1单株和BC3F2株行接种鉴定,BC3F1中RM224位点上杂合基因型的61个植株表现为抗至中抗,RM224位点上滇粳优1号纯合基因型单株都表现为感病;由RM224位点杂合基因型BC3F1单株衍生的61个BC3F2代株行表现为抗、感分离。     

民企老板十年民告官的"精神胜诉"--访河南省某县种子广场总经理张书智

在河南省某县种子广场,张书智在自家种子门市部里办起了"普法超市".房间里两架一人多高的书柜中,摆满了有关法律书报杂志,有 3000多册书、 1O00多份杂志.凡是到这里的农民均可享受免费法律咨询、协助起草法律文书、借阅书报杂志等服务."普法超市"开办两个多月,接待了来自四面八方的"顾客" 800余人次,收到全国各地的咨询信函 500多封,他们所遇到法律方面的困惑和难题均得到满意的解答.     

Controlled pollination transfer of a nuclear male-sterile gene from a diploid to a tetraploid watermelon line

Summary A recessive male-sterility (ms) gene was transferred from a diploid to a tetraploid watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) line through a series of controlled pollinations. Progeny testing and morphological characteristics confirmed the development of tetraploid lines containing the ms gene. The possible use of this gene transfer system in the improvement of tetraploid watermelon cultivars and the use of male-sterile tetraploids in the production of seedless triploid watermelons is discussed.     

Prediction of the Line Value of a Genotype from a Top Cross with a Single Cross Hybrid

With the assumption of biallelism it is shown that differences in line values of genotypes from a random mating population can be predicted by the differences of values in top cross progenies with a heterozygous tester. This prediction is also valid in the case of multiallelism with a constant degree of dominance for each pair of alleles and if the tester is heterozygous for the more “distant” alleles. With an arbitrary tester, the efficiency of the prediction is affected by the proportion of the loci which are heterozygous for the more distant alleles. However, with the assumptions considered on multiallelism, with partial to complete dominance, the correlation between line value and combining ability with the tester is expected to be high for a large range of the repartition ot the loci. A two tester top cross design using highly complementary lines, could also be used.     

Solanum scabrum—a potential source of a coloring plant extract

The objective of this study was to examine the potential of Solanum scabrum to provide a colorant for food. We conducted a field trial with eight accessions from four different sources and recorded both morphological variability and fruit yield differences between accessions. Further, anthocyanin and glucoalkaloid concentrations were determined. The accessions could be assigned to two distinct groups: a leafy vegetable type with toxic fruits used in Africa and a berry type with edible fruits known as Garden Huckleberry in North America, but both types had edible leaves with low glucoalkaloid concentrations. The leafy vegetable type set not much fruit. In contrast, the berry type yielded on average 800–900 g berries per plant with remarkable high anthocyanin concentrations of 8.1–13.9 g kg⁻¹ fresh weight, calculated as petunidin 3-p-(coumaryl-runtinoside)-5-glucoside. Thus, S. scabrum can serve as a source for natural anthocyanin pigments. In particular, two accessions with a high fruit yield were promising candidates as a berry crop. One had the best anthocyanin concentration of the examined material and the other one had a low percentage of unripe berries as a further advantage.     

Economic Impact of a Port on a Regional Economy: Note

ABSTRACT This paper attempts to identify and adjust for several shortcomings of previous port impact studies in the estimation of primary port economic impact. These shortcomings are found to create the potential for both positive and negative bias. Also presented in this paper is a technique for circumventing several practical problems in the estimation of secondary economic impact. These adjustments are applied to estimate the economic impact of the Port of Hampton Roads, Virginia.     

The breeding of a winter rye variety with a good eelworm-resistance

Summary Some local varieties of winter rye possess a good eelworm-resistance but have too weak a straw and produce an insufficient quantity of seed on healthy soil or on fields which are slightly infested.On the farm Heertveld, belonging to the C.I.V. Breeding Station, a rye variety has been developed from a cross between Ottersum rye and Petkus winter rye, and it showed a good resistance to the stem eelworm (Ditylenchus dipsaci). The new variety which was included in the Dutch List of Varieties of 1953, distinguished itself by a rapid and good soil coverage and strikingly stiff straw.On investigation by the I.P.O. it was established (after artificial inoculation) that 25% of the plants of Heertveld rye were not affected, 50% were slightly damaged and 25% were heavily attacked. However, in the field it shows a good resistance, due to a good recovery.At the Breeding Station selection for eelworm resistance and also for other desirable features is continued and at present such progress has been made that the Heertveld rye now approaches the production capacity of Petkus.     

A mutant of a mutant of a mutant of a...: Irradiation of progressive radiation-induced mutants in a mutation-breeding programme with Chrysanthemum morifolium Ram.

Summary Radiation-induced sports in Chrysanthemum morifolium Ram. have been reported for several years. It has become an everyday practice to produce flower-colour mutants from outstanding cross-breeding products, even before they are distributed for the commercial production of cut flowers.One of the most successful and recent examples is that of cv. Horim, of which hundreds of mutants were produced by successive use of radiation-induced mutants in the mutation-breeding programme. Over about 4 years a variety of flower-colour mutants was obtained, not only largely including the outstanding characteristics of the original cultivar but sometimes even with an appreciable improvement in quality and yield. It is expected that the latter types, the Miros group, will soon completely supersede the spontaneous or radiation-induced Horim sports and mutants and take over the leading position of the Horim group in the production of all-year-round (AYR) cut flowers.     

Quantitative trait loci for grain yield and yield components in a cross between a six-rowed and a two-rowed barley

Summary The positions of quantitative trait loci (QTL) for yield and yield components were estimated using a 85-point linkage map and phenotype data from a F₁-derived doubled haploid (DH) population of barley. Yield and its components were recorded in two growing seasons. Highly significant QTL effects were found for all traits at several sites in the genome. A major portion of the QTL was found on chromosome 2. The effect of the alleles in locus v on thousand grain weight and kernels per ear explained 70–80% of the genetic variation in the traits. QTL × year interaction was found for grain yield. Several different QTL were found within the two-rowed DH lines compared to those found in the six-rowed DH lines. Epistasis between locus v and several loci for yield and yield components indicates that genes are expressed differently in the two ear types. This may explain the difficulties of selecting high yielding lines from crosses between two-rowed and six-rowed barley.Abbreviations DH doubled haploid - QTL quantitative trait locus/loci - RAPD random amplified polymorphic DNA - RFLP restriction fragment length polymorphism - T. Prentice Tystofte Prentice - V. Gold Vogelsanger Gold     

审时度势 把握时机 开创种子工作新局面

随着《中华人民共和国种子法》(以下简称《种子法》)的颁布实施及其相应配套法规的相继出台 ,种子行业将面临激烈的变革 ,原有的格局将被打破 ,并进入重组状态。《战国策》中言道 :“时势者 ,百事之长也。”据此可说明认清行业发展大趋势 ,并遵循客观规律加以利用是制胜的前提。只有这样 ,才能把握机遇 ,迎接挑战 ,立于不败之地。为此 ,对种子行业的发展趋势做一些分析。1　中小型经营单位的发展方向和出路所谓中小型经营单位是指经营种子量在 5 0万～15 0万千克 ,制种基地在 5 0 0 0亩左右 ,并拥有一定数量固定客户和市场 ,但缺乏自己拳头…