东乡普通野生稻与栽培稻苗期抗旱性的比较

干旱影响水稻生长发育,不论什么时期发生最终都导致产量损失。研究水稻资源抗旱性有助于水稻抗旱改良和稳定干旱胁迫下水稻的产量。东乡普通野生稻被公认为是栽培稻的祖先,对增强水稻抗旱性可能十分重要。对4份来自3个仅存的居群的东乡野生稻与15份栽培稻进行苗期抗旱性比较,考察了3次重复的盆栽土培试验中8个抗旱指标。表明东乡普通野生稻比栽培稻更为抗旱,表现在最大根长、茎长、根干重、根鲜重、根干鲜重比及抗旱指数等6个性状,而不表现在根数及根茎长比;其中茎长、最长根长、根干重、根鲜重及根系相对含水量对水稻苗期抗旱性影响更大。采用抗旱指数和抗旱总级别值法对水稻抗旱性进行评定,结果表明4份东乡野生稻材料间的抗旱性存在很大差异,且来水桃树下居群的抗性最高,东乡野生稻抗旱性可能与其原生境状况有关。结果认为东乡普通野生稻可作为栽培稻抗旱改良的遗传资源。     

普通野生稻中增产相关QTL的发掘

普通野生稻(Oryza Rufipogon)是重要的遗传资源,发掘其优良等位基因将对水稻遗传改良产生重要影响。文章从以珍汕97为轮回亲本,普通野生稻为供体的BC2F1群体中选择一个与珍汕97表型明显不同的单株BC2F1-15,经过连续自交获得回交重组自交系BC2F5群体。均匀分布于12条染色体的126个多态性SSR(Simplesequence repeats)标记基因型分析,发现BC2F1-15单株在30%的标记位点为杂合基因型;利用该群体共检测到4个抽穗期、3个株高、4个每穗颖花数、2个千粒重和1个单株产量QTL。在第7染色体RM481-RM2区间,检测到抽穗期、每穗颖花数和产量QTL,野生稻等位基因表现增效作用;其他3个每穗颖花数QTL位点,野生稻等位基因也均具有增效作用。结果表明野生稻携带有增产相关的等位基因,这些有利等位基因无疑是水稻遗传改良可资利用的新资源。     

小粒野生稻与栽培稻杂种及回交后代的特征分析

小粒野生稻（Oryza minuta）,是栽培稻遗传改良的宝贵资源,本研究通过杂交和回交结合胚拯救技术获得了小粒野生稻与栽培稻的种间杂种及回交后代,调查了杂种与各回交后代的交配率和染色体数目,并运用175对均匀分布的SSR标记对双亲和92份二倍体的BC3F1植株进行了分析.结果表明,杂种F1,BC1,BC2和BC3的交配率分别为5.58%,0.11%,0.37%和1.62%;杂种染色体数目为36（ABC）,回交后代的染色体数目为24～48;小粒野生稻与栽培稻间SSR标记的多态性概率为93.2%;在92份二倍体的BC3F1植株中,小粒野生稻渗入片段的数目、长度、总的大小及其所占全基因组的百分数分别为24.1,17.8,438.4cM和26.2%.同时还评价了杂种和回交后代的部分农艺性状和对水稻白叶枯病的抗性表现.这些材料可以用于鉴定来自于小粒野生稻的有利基因和产量相关性状的数量性状基因座（quantitative trait loci,QTL）,为栽培稻的遗传改良提供新的操作平台.     

AB-QTL法定位广东高州野生稻谷粒外观性状和粒重基因

以广东高州野生稻为供体亲本,在栽培稻粤香占的遗传背景下构建了一套高代回交BC3F1群体,共计245个株系.选择117对在双亲间有多态性的SSR引物,对BC3F1株系进行了基因型分析.利用AB-QTL分析法对谷粒外观性状和粒重进行QTL分析,结果表明粒长、粒宽、粒长宽比以及粒重4个性状共检测到23个QTL,分布于水稻第1、2、3、4、5、6、8和11染色体上,单个QTL的贡献率范围为3.77%～28.67%.其中有6个QTL的贡献率超过20%,分别是控制粒宽的qGW-11-1,控制长宽比的qLWR-2和qLWR-11,控制粒重的qGWt-5-1、qGWt-5-2和qGWt-11-1.与现有的以普通野生稻为供体的相关研究比较,本研究所定位的基因数目较多,表明高州野生稻亟需研究利用.     

Bph3在栽培稻和药用野生稻中的BAC-FISH比较物理定位(英)

用栽培稻 (OryzasativaL .)遗传图第四连锁群中与抗褐稻虱基因Bph3紧密连锁的RFLP标记RZ6 9及筛选出来的BAC克隆 38J9作探针 ,对药用野生稻 (O .officinalisWellexWatt)和栽培稻荧光原位杂交 ,供试标记RZ6 9及38J9均被定位于药用野生稻和栽培稻第 4染色体的短臂上 ,药用野生稻杂交信号的百分距分别为 2 2 .12± 3.4 4和2 0 .0 0± 5 .4 0 ,而栽培稻均为 0。在栽培稻中 ,信号检出率相应地为 6 .2 9%和 5 6 .10 % ,在药用野生稻中则为 6 .14 %和 5 0 .0 0 %。BAC克隆和RFLP标记探针杂交信号的百分距十分接近 ,说明在栽培稻和野生稻中RFLP标记RZ6 9都在同一BAC克隆的大插入片段中。由此推知 ,药用野生稻与抗性基因Bph3的同源顺序就在第 4染色体信号出现的相应位置。在未封阻的情况下 ,药用野生稻的BAC杂交在多条染色体上具有信号 ,这表明它和栽培稻的Cot_1DNA重复顺序也在一定程度上具有同源性。药用野生稻第 4染色体是根据栽培稻与药用野生稻的比较遗传图选用与Gm_6连锁的RG2 14通过FISH确定的。讨论了栽培稻BAC克隆对药用野生稻比较原位杂交物理作图的可行性问题。     

云南元江普通野生稻株高和抽穗期QTL定位研究

以云南元江普通野生稻为供体亲本,在特青的遗传背景下构建了一套BC3高代回交群体。利用117个SSR标记分析383个BC3F2株系的基因型,采用单标记分析法对控制元江普野株高和抽穗期的QTL进行分析。在北京和合肥两个地点试验结果表明,控制株高的QTL分布在第1染色体上,在RM104附近有一个QTL,与sd-1位置相当,其对表现型变异的贡献率在两个地点分别为27％和28％,其加性效应值分别为26．24cm和26．28cm,来自野生稻的等位基因显著提高回交群体的株高;在第1、3、7、8、11染色体共检测到6个控制抽穗期QTL,其中第8染色体RM25附近控制抽穗期的QTL在两个地点的贡献率分别为13％和15％,加性效应值为4．60d和3．65d,来自野生稻的等位基因使回交群体抽穗期延迟。     

基于染色体置换系的野生稻抽穗期及紫色性状QTL的鉴定

利用一套以9311为背景的普通野生稻染色体片段置换系群体为研究材料,进行野生稻相关QTL的定位与基因的鉴定。在多年多点的抽穗期调查数据基础上,结合200多个分子标记引物的基因型鉴定结果,定位到11个与抽穗期相关的QTL;选取携带相关QTL导入片段的两个置换系进一步研究,发现2个抽穗期主效QTL均为已克隆基因的等位基因。利用叶鞘、稃尖、柱头颜色与9311差异显著的一个单片段置换系定位到来自野生稻的紫色性状基因Or C,初步鉴定与栽培稻的等位基因功能不同。这些结果再次表明染色体片段置换系是行之有效的QTL定位以及基因发掘的遗传群体。通过对抽穗期、紫色性状相关QTL的定位与基因的鉴定,为进一步的功能研究提供了基因资源。     

载培稻与普通野生稻两个重要分类性状花药长度和柱头外露率的QTL分析

用江西东乡普通野生稻（简称东乡普野）和桂朝2号的115株的BC1群体,构成了1张长度为1418．2cM,包含120个RFLP标记的遗传图谱,该图谱除第1染色体短臂上的标记的顺序与日本水稻基因组计划发表的图谱不同外,其他染色体上相对应的标记的顺序及标记之间的遗传距离基本一致,对控制花药长度和柱头外露率这两个载培稻和野生稻的重要分类性状的TQL分析结果表明,控制花药长度的2个QTLs分别位于第2染色体C424－G39和第9染色体C2U807－C1263间,控制柱头外露率的2个QTLs分别位于第5染色体R2289－R1553间和第8染色体G1149－R1963间,这两个重要分类性状的QTLs定位,为进一步研究野生稻进化到载培稻的分子进化机理提供了有益的信息。     

茶陵野生稻导入系遗传分析及重要性状相关QTL鉴定

普通野生稻是栽培稻的祖先种,从野生稻中挖掘栽培稻中已丢失或削弱了的优异基因是保证水稻高产稳产的一个重要手段。本研究以茶陵野生稻染色体片段导入系群体为研究材料,使用均匀分布于12条水稻染色体上的136个多态性分子标记,对其遗传背景进行检测。平均每个导入系携带24个导入片段,导入片段平均长度为16.1 cM,导入片段覆盖野生稻基因组的87.89%。结合两个环境中的性状调查,鉴定到与6个产量性状相关的18个QTLs,其中6号染色体上与粒宽有关的QTL在两个环境中被连续检测到。除此之外,还鉴定到5个与发芽期耐冷性有关的QTLs。     

云南元江普通野生稻穗颈维管束和穗部性状的QTL分析

以云南元江普通野生稻为供体亲本,籼稻品种特青为轮回亲本构建高代回交群体,用SSR标记构建连锁图谱,在第1、2、3、4、7和10染色体上定位到7个控制穗颈大维管束数的QTL,在第1、2、3、4和8染色体上定位到5个控制穗颈小维管束数的QTL,在第11和12以外的10条染色体上,共定位到15个控制穗一、二次枝梗数和穗颖花数QTL。来自野生稻的等位基因大多表现负效,能显著减少群体的穗颈维管束数、枝梗数和颖花数,说明从野生稻演化成栽培稻的过程中,可能淘汰了一些对产量不利的QTL,保留了有利的QTL。相当一部分控制穗颈维管束数、枝梗数及颖花数的QTL在染色体上成簇分布或紧密连锁,且加性效应的方向一致,从理论上解释了这些性状表型显著相关的遗传基础,同时也说明在人工选择或自然选择下,这些性状可能存在平行进化或协同进化的关系。     

Identification of Quantitative Trait Loci Controlling Drought Tolerance at Seedling Stage in Chinese Dongxiang Common Wild Rice (Oryza rufipogon Griff.)

Common wild rice (Oryza rufipogon Griff.) is the ancestor of cultivated rice (O. sativa L.), which has a greater genetic diversity and important traits that remain to be employed in cultivated rice. In this study, a set of introgression lines (BC₄F₅ and/or BC₄F₆) carrying various introgressed segments from common wild rice, collected from Dongxiang county, Jiangxi Province, China, in the background of an Indica (O. sativa L. ssp. indica) cultivar, Guichao 2, was used. A total of 12 drought-related quantitative trait loci (QTL) were identified by investigating drought tolerance of introgression lines under 30% PEG treatment at the young seedlings stage. Of these QTLs, the alleles of 4 QTLs on chromosome 2, 6 and 12 from Dongxiang common wild rice were responsible for increased drought tolerance of the introgression lines. In particular, a QTL qSDT12-2, near RM17 on chromosome 12, was consistently detected in different replications, and expressed stably under PEG stress throughout the study. It was also found that the QTLs located on different chromosomes might express at different stages.     

Identification of a Drought Tolerant Introgression Line Derived from Dongxiang Common Wild Rice (O. rufipogon Griff.)

Construction of introgression lines using cultivated rice as recipient and wild rice is a novel approach to explore primitive and broad genetic resources in rice breeding. We recently generated a set of 159 introgression lines via a backcrossing program using an elite Indica cultivar rice Guichao 2 (O. sativa L. ssp. indica) as recipient and a common wild rice Dongxiang accession (O. rufipogon Griff.) as donor. In this study, we have evaluated the previously constructed 159 introgression lines for drought-tolerance. A total of 12 quantitative trait loci (QTLs) related to drought tolerance were mapped. Furthermore, a drought tolerant introgression line, IL23, was identified and characterized. Genotype analysis of IL23 demonstrated that IL23 contained two QTLs associated with drought tolerance, qSDT2-1 and qSDT12-2, which were located on chromosome 2 and 12 within the two introgressed segments derived from the common wild rice, respectively. Physiological characterization, including measurement of water loss, osmotic potential, electrolytical leakage, MDA content, soluble sugars content and the leaf temperature, revealed that IL23 showed the characteristics associated with drought tolerance. Identification and characterization of IL23 would provide a useful basis for isolation of novel genes associated with drought tolerance and for molecular breeding of drought tolerant rice. Furthermore, the results in this study indicated that construction of introgression lines from common wild rice should be an appropriate approach to obtain favorable genetic materials.     

覆盖野生稻基因组的染色体片段替换系的构建及其米质相关数量性状基因座位的鉴定

染色体片段替换系（CSSL）是基因组水平快速初步定位数量性状基因座位（QTL）的良好材料,而水稻的品质性状是多基因控制的数量性状,因此可用替换系鉴定控制水稻品质性状的QTL。本文用分子标记辅助选择技术（MAS）构建了由133个株系组成的以‘特青’（籼稻品种）为轮回亲本,以海南的一种普通野生稻为供体亲本,覆盖绝大部分野生稻基因组的染色体片段替换系。利用这套替换系,初步定位了控制稻米外观和理化品质性状的15个QTL,为今后水稻品质性状QTL的克隆以及稻米品质相关性状的改良提供了依据。     

Molecular tagging of genes for brown planthopper resistance and earliness introgressed from Oryza australiensis into cultivated rice, O. sativa.

Restriction fragment length polymorphism analysis was carried out to tag the alien genes for brown planthopper (BPH) resistance and earliness introgressed from wild species Oryza australiensis into cultivated rice, O. sativa L. One introgression line (IR65482-4-136-2-2), resistant to biotypes 1, 2, and 3 of BPH and early in flowering, was selected from BC2F4 of the cross between O. sativa (IR31917-45-3-2) and O. australiensis (accession 100882). Recurrent parent, O. australiensis, and introgression line were surveyed for RFLP using probes of chromosomes 10 and 12. Two probes, RG457 and CDO98, detected introgression from O. australiensis. Cosegregation between introgressed characters and molecular markers was studied in F2 derived from the cross between the introgression line and recurrent parent. The gene for BPH resistance is linked with RG457 of chromosome 12 at a distance of 3.68 +/- 1.29 cM, and the gene for earliness is linked with CDO98 of chromosome 10 at a distance of 9.96 +/- 3.28 cM. Such close linkage is useful in marker-based selection while transferring BPH resistance from introgression line into other elite breeding lines. Introgression at the molecular level indicates that the mechanism of alien gene transfer is probably genetic recombination through crossing over rather than substitution of whole or large segment of chromosomes of wild species.     

Analysis of QTLs for yield-related traits in Yuanjiang common wild rice （Oryza rufipogon Griff.）

Using an accession of common wild rice(Oryza rufipogon Griff.)collected from Yunnjiang County,Yunnan Province,China,as the donor and an elite cnltivar 93-11,widely used in two-line indica hybrid rice production in China,as the recurrent parent,an advanced backcross populations were developed.Through genotyping of 187 SSR markers and investigation of six yield-related traits of two generations(BC4F2 and BC4F4),a total of 26 QTLs were detected by employing single point analysis and interval mapping in both generations.Of the 26 QTLs,the alleles of 10(38.5%)QTLs originating from O.rufipogon had shown a beneficial effect for yield-related traits in the 93-11 genetic background.In addition,five QTLs controlling yield and its components were newly identified,indicating that there arc potentially novel alleles in Yuanjiang common wild rice.Three regions underling significant QTLs for several yield-related traits were detected on chromosome 1,7 and 12.The QTL clusters were founded and corresponding agronomic traits of those QTLs showed highly significant correlation,suggesting the pleiotropism or tight linkage.Fine-mapping and cloning of these yield-related QTLs from wild rice would be helpful to elucidating molecular mechanism of rice domestication and rice breeding in the future.     

Quantitative trait loci underlying domestication- and yield-related traits in an Oryza sativa x Oryza rufipogon advanced backcross population

To understand the genetic characteristics of the traits related to differentiation between cultivated rice and its wild progenitor, genetic factors controlling domestication- and yield-related traits were identified using a BC3F2 population derived from an accession of common wild rice (donor, Oryza rufipogon Griff.) collected from Yuanjiang, Yunnan province, China, and an indica cultivar, Teqing (recipient, Oryza sativa L.). A genetic linkage map consisting of 125 simple sequence repeat (SSR) markers was constructed. Based on the phenotypes of the 383 BC3F2 families evaluated in two environments, two domestication-related morphological traits, panicle shape and growth habit, were found to be controlled by single Mendelian factors. This implies that the recessive mutations of single genes controlling some morphological traits could have been easily selected during early domestication. By single-point analysis and interval mapping, 59 putative quantitative trait loci (QTLs) that influence 11 quantitative traits were detected at two sites, and 37.5% of the QTL alleles originating from O. rufipogon had a beneficial effect for yield-related traits in the Teqing background. Regions with significant QTLs for domestication- and yield-related traits were detected on chromosomes 1, 4, 5, 7, 8, and 12. Fine mapping and cloning of these domestication-related genes and QTLs will be useful in elucidating the origin and differentiation of Asian cultivated rice in the future.     

东乡野生稻耐冷渐渗系的细胞学观察及SSR分析

以前期鉴定筛选的2个东乡野生稻强耐冷渐渗系(IL5243和IL5335)为试材,研究其减数分裂时期的染色体行为特征及外源基因的渗入分子证据。结果表明:(1)IL5243和IL5335中正常减数分裂的花粉母细胞分别达89.93%和90.22%,最终形成正常的成熟花粉粒,花粉离体萌发率分别为(83.03±2.82)%和(81.96±1.73)%,与受体亲本无显著性差异。(2)在减数分裂I中,2个耐冷渐渗系均观察到低频率异常染色体行为,如单价体、"8"字型二价体、多价体,以及后期I有少数花粉母细胞(3.95%～5.15%)存在落后染色体等,表明其染色体组之间发生了交换和重组;在粗线期,2个强耐冷渐渗系均观察到较高频率(IL5243和IL5335分别为27.0%和38.9%)的双核仁,而其双亲都是单核仁。(3)SSR标记和Structure分析进一步证实了栽培稻和野生稻染色体组间发生了交换重组,东乡野生稻部分DNA片段已渗入到强耐冷渐渗系中,这为水稻耐冷基因的挖掘与利用奠定了重要基础。     

Mapping QTLs associated with drought avoidance in upland rice

The identification of molecular markers linked to genes controlling drought resistance factors in rice is a necessary step to improve breeding efficiency for this complex trait. QTLs controlling drought avoidance mechanisms were analyzed in a doubled-haploid population of rice. Three trials with different drought stress intensities were carried out in two sites. Leaf rolling, leaf drying, relative water content of leaves and relative growth rate under water stress were measured on 105 doubled haploid lines in two trials and on a sub-sample of 85 lines in the third one. Using composite interval mapping with a LOD threshold of 2.5, the total number of QTLs detected in all trials combined was 11 for leaf rolling, 10 for leaf drying, 11 for relative water content and 10 for relative growth rate under stress. Some of these QTLs were common across traits. Among the eleven possible QTLs for leaf rolling, three QTLs (on chromosomes 1, 5 and 9) were common across the three trials and four additional QTLs (on chromosomes 3, 4 and 9) were common across two trials. One QTL on chromosome 4 for leaf drying and one QTL on chromosome 1 for relative water content were common across two trials while no common QTL was identified for relative growth rate under stress. Some of the QTLs detected for leaf rolling, leaf drying and relative water content mapped in the same places as QTLs controlling root morphology, which were identified in a previous study involving the same population. Some QTL identified here were also located similarly with other QTLs for leaf rolling as reported from other populations. This study may help to chose the best segments for introgression into rice varieties and improvement of their drought resistance.     

水稻耐亚铁毒QTLs的定位

亚铁毒是潜育性水稻土中限制水稻产量的主要因子。利用龙杂8503／IR64的F2和等价的F3群体,在营养液中培养来定位耐亚铁毒的QTLs。通过构建101SSR标记的遗传连锁图谱来确定耐亚铁毒QTLs的位置和特性。借助叶片棕色斑点指数、株高和最大根长3个性状,利用营养液在水稻苗期来评价F2单株、F3群体和亲本龙杂8503、IR64,共检测到叶片棕色斑点指数、株高和最大根长的QTLs20个,分布在水稻的10条染色体上,表明这些性状受多基因控制。控制叶片棕色斑点指数的QTLs分别定位在第1染色体的RM315-RM212、第2染色体的RM6-RM240和第4染色体的RM252-RM451之间。与前人的研究结果比较发现：1）位于第4染色体RM252-RM451之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上控制叶绿素含量减少的QTL的位置一致。另一个位于第1染色体的RM315-RM212之间的控制叶片棕色斑点指数的QTL与水稻功能图谱上位于C178-R2635之间控制叶绿素含量的QTL连锁。2）位于第2染色体RM6-RM240之间的第3个控制叶片棕色斑点指数的QTL与位于RZ58-CD0686的控制钾吸收的QTL连锁。