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1.
Bacterial blight (BB) is the most economically damaging disease of rice in Asia and other parts of the world. In this study, a multiplex PCR genotyping method was developed to simultaneously identify genotypes of five BB resistance genes, Xa4, xa5, Xa7, xa13 and Xa21. The resistance R alleles were amplified using five functional markers (FMs) to generate amplicons of 217, 103, 179, 381 and 595 bp in IRBB66. Amplicons of 198, 107, 87, 391 and 467 bp corresponded to susceptible alleles in Taiwanese japonica rice cultivars. In backcross breeding programmes, the multiplex PCR assay was integrated into selection from a population using BB resistance donor IRBB66 crossed to rice cultivar ‘Tainung82’. Two plants with homozygosity for Xa4, xa5, Xa7, xa13 and Xa21 were selected from 1100 BC2F2 plants. In addition, the five BB resistance genes were also accurately identified in F2 populations. This multiplex PCR method provides a rapid and efficient method for detecting various BB resistance genes, which will assist in pyramiding genes to improve durability of BB resistance in Taiwanese elite rice cultivars.  相似文献   

2.
Wheat landraces carry abundant genetic variation in heading and flowering times. Here, we studied flowering-related traits of two Nepalese varieties, KU-4770 and KU-180 and a Japanese wheat cultivar, Shiroganekomugi (SGK). These three wheat varieties showed similar flowering time in a common garden experiment. In total, five significant quantitative trait loci (QTLs) for three examined traits, the heading, flowering and maturation times, were detected using an F2 population of SGK/KU-4770. The QTLs were found at the Ppd-1 loci on chromosomes 2B and 2D and the 2B QTL was also confirmed in another F2 population of SGK/KU-180. The Ppd-D1 allele from SGK and the Ppd-B1 alleles from the two Nepalese varieties might be causal for early-flowering phenotype. The SGK Ppd-D1 allele contained a 2-kb deletion in the 5′ upstream region, indicating a photoperiod-insensitive Ppd-D1a allele. Real-time PCR analysis estimating the Ppd-B1 copy number revealed that the two Nepalese varieties included two intact Ppd-B1 copies, putatively resulting in photoperiod insensitivity and an early-flowering phenotype. The two photoperiod-insensitive Ppd-1 homoeoalleles could independently contribute to segregation of early-flowering individuals in the two F2 populations. Therefore, wheat landraces are genetic resources for discovery of alleles useful for improving wheat heading or flowering times.  相似文献   

3.
Germplasm improvement is a conceivable solution for increasing food production in developing countries. The objectives of the present study were to incorporate the genetic diversity of two Nicaraguan common bean landraces into a segregating population and to evaluate its potential as breeding material. Adapted landraces PV0006 and PV0023 were selected as parents for single crosses based on molecular and phenotypic characteristics. The results indicate that we succeeded in reshuffling most of the genetic diversity of both parents into a segregating population. The level of allele recombinations suggests that theoretically between 128 and 1024 different pure lines could be obtained. We found putative associations between alleles and yield‐determinant components. Computer simulations demonstrated that the pedigree method and the marker selection of the most segregating individuals in the F1 generation could improve the genetic gains for yield. These findings expose the potential of this segregating population and the feasibility of local landraces for bean improvement.  相似文献   

4.
利用SSR标记分析了16份和14份代表云南不同生态地区糯玉米、爆裂玉米地方种的遗传多样性。从96对SSR引物中分别筛选出分布于玉米基因组10条染色体上的61对引物和43对引物,每对引物可以分别稳定地检测到1～12个和1～13个多态性片段,糯玉米共226个,平均为3.70个,片段大小介于70～700 bp之间;爆裂玉米共232个,平均检测的多  相似文献   

5.
Flag leaf angle (FLA) in rice (Oryza sativa L.) is one of the important traits affecting F1 seed production by mechanization. To elucidate the genetic mechanism of FLA and mine favorable marker alleles for F1 seed production in rice, we performed a genome-wide association study using phenotypic data over 2 years and genotypic data of 262 pairs of simple sequence repeat (SSR) markers collected from 441 rice accessions. We detected seven SSR marker loci associated with FLA and four loci were novel. The four newly found loci were RM6266 on chromosome 3, RM348 on chromosome 4, RM258 on chromosome 10 and RM7303 on chromosome 11. We found a total of 27 favorable alleles, of which four, i.e., RM348-130 bp, RM7303-90 bp, RM258-180 bp, and RM4835-230 bp, had phenotypic effects larger than 10°. Nine combinations, which increased FLA by 45.7°–94.7° through pyramiding the favorable alleles contained in seven typical accessions, were predicted.  相似文献   

6.
Sheath blight (ShB) disease caused by Rhizoctonia solani is one of the major threats to rice crop world-wide. Progress in breeding for resistant rice varieties is limited due to lack of highly resistant germplasm against sheath blight. In present study, diverse rice landrace were phenotyped against R. solani and resistant and moderately resistant sources were identified from the panel of 134 germplasm pool. Landrace Nizam shait showed resistance, where as Bidar local-2, Jigguvaratiga, NavaliSali, Jaddu and Tetep exhibited moderate resistance. Population structure was analysed by genotyping the accessions using 63 genome wide Rice Microsatellite markers which divided the mapping panel into two groups. Association mapping using GLM?+?Q model of TASSEL indicated significant association between twenty-one marker loci on nine chromosomes with ShB resistance with phenotypic variation (R2) ranging 3.02–22.71 per cent. We identified 13 new markers to be associated with ShB resistance. The present work validates previously identified eight markers flanking different shB QTLs. None of the allele from the tested markers was unique and common among resistant and moderately resistant landraces identified in this work except allele 420 bp of RM337 and allele 310 bp of RM5556 noticed only in Tetep. Our findings predict the possible presence of unreported QTL region in marker interval of RM337 and RM5556 on chromosome 8 for ShB resistance in Tetep which invites further investigation.  相似文献   

7.
Rice grain shape and yield are usually controlled by multiple quantitative trait loci (QTL). This study used a set of F9–10 recombinant inbred lines (RILs) derived from a cross of Huahui 3 (Bt/Xa21) and Zhongguoxiangdao, and detected 27 QTLs on ten rice chromosomes. Among them, twelve QTLs responsive for grain shape/ or yield were mostly reproducibly detected and had not yet been reported before. Interestingly, the two known genes involved in the materials, with one insect-resistant Bt gene, and the other disease-resistant Xa21 gene, were found to closely link the QTLs responsive for grain shape and weight. The Bt fragment insertion was firstly mapped on the chromosome 10 in Huahui 3 and may disrupt grain-related QTLs resulting in weaker yield performance in transgenic plants. The introgression of Xa21 gene by backcrossing from donor material into receptor Minghui 63 may also contain a donor linkage drag which included minor-effect QTL alleles positively affecting grain shape and yield. The QTL analysis on rice grain appearance quality exemplified the typical events of transgenic or backcrossing breeding. The QTL findings in this study will in the future facilitate the gene isolation and breeding application for improvement of rice grain shape and yield.  相似文献   

8.
用SSR标记对云南爆裂玉米地方种遗传多样性的研究   总被引：2，自引：0，他引：2  
吴渝生  顾红波  李俊流 《种子》2004,23(1):9-12
本文利用SSR标记分析了14份代表云南不同生态地区的爆裂玉米种质的遗传多样性.从96对SSR引物中筛选出分布于玉米基因组10条染色体上的43对引物,每对引物可以稳定地检测到1～13个多态性片段,共232个,平均为5.40个,片段大小介于65～490bp之间.检测出1个等位基因(allele)的引物有3对,占所筛选引物的7.0%;检测出12个和13个等位基因的引物也有3对,占所筛选引物的7.0%;其余37对引物检测出的等位基因一般在2～9个,占所筛选引物的86.0%.结果表明云南爆裂玉米地方种质具有较高的遗传多样性.通过聚类分析将云南爆裂玉米分为3个类群,4个亚群,聚类结果与云南不同海拔地势的变化走向基本相符.  相似文献   

9.
水稻抗白叶枯病新基因Xa32（t）的鉴定和初步定位   总被引：2，自引：0，他引：2  
通过多菌系接种鉴定及抗谱分析,并与目前国际上已知抗白叶枯病基因比较,证明在水稻抗源C4064中含有一个新的抗白叶枯病基因,暂命名为Xa32(t)。应用分离集团分析法(BSA),借助SSR和EST等分子标记,对该基因进行了分子标记定位。通过对F2分离群体及F3家系单株进行遗传连锁性检测,发现6个位于水稻第11染色体长臂末端的分子标记RM27256、RM27274、RM2064、ZCK24、RM6293和RM5926与Xa32(t)基因连锁。它们与Xa32(t)基因间的遗传距离分别为2.1、1.0、1.0、0.5、1.5和2.6 cM。其中标记RM6293和RM5926位于染色体近端粒一侧,其他4个标记RM27256、RM27274、RM2064和ZCK24位于基因的另一侧。将Xa32(t)定位在水稻第11染色体长臂末端2.0 cM范围内。  相似文献   

10.
水稻抗白叶枯病新基因Xa32（t）的鉴定和初步定位   总被引：1，自引：0，他引：1  
通过多菌系接种鉴定及抗谱分析,并与目前国际上已知抗白叶枯病基因比较,证明在水稻抗源C4064中含有一个新的抗白叶枯病基因,暂命名为Xa32(t)。应用分离集团分析法(BSA),借助SSR和EST等分子标记,对该基因进行了分子标记定位。通过对F2分离群体及F3家系单株进行遗传连锁性检测,发现6个位于水稻第11染色体长臂末端的分子标记RM27256、RM27274、RM2064、ZCK24、RM6293和RM5926与Xa32(t)基因连锁。它们与Xa32(t)基因间的遗传距离分别为2.1、1.0、1.0、0.5、1.5和2.6 cM。其中标记RM6293和RM5926位于染色体近端粒一侧,其他4个标记RM27256、RM27274、RM2064和ZCK24位于基因的另一侧。将Xa32(t)定位在水稻第11染色体长臂末端2.0 cM范围内。  相似文献   

11.
利用等位基因特异扩增快速检测水稻香味基因   总被引：12，自引：0，他引：12  
水稻香味受隐性基因控制, 杂合材料不表现出香味, 因此在香稻选育中需要寻找一种快速、简便的香味基因检测方法。本试验通过等位基因特异扩增(ASA)方法对9个香稻和3个非香稻品种 (品系), 以及3个香稻/非香稻组合的F1的香味基因, 进行快速检测。结果显示, 纯合非香稻可获得长度为585和355 bp的两条带, 纯合香稻可获得长度为577和257 bp的两条带, 杂种F1可获得长度为355、257和580 bp左右的3条带。供试材料的分子检测结果与香味基因型完全相符, 所用方法快速有效, 可应用于香稻育种实践。  相似文献   

12.
To clarify the genetic mechanism which controls the variation in amylose content among nonwaxy landraces of foxtail millet, the inheritance of different starch types in endosperm was examined by I2-KI staining. The level of starch granule bound protein in foxtail millet endosperm was also analyzed using SDS-PAGE. The segregation for starch types in F2 and F3 seeds determined by I2-KI staining showed that there are three different alleles at the waxy (wx) locus. A major protein bound to starch granules was detected in nonwaxy endosperm but it was absent in most of the waxy endosperm, suggesting that the protein is the Wx gene product which is responsible for the synthesis of amylose in endosperm. The level of Wx protein proportionally corresponded to the amylose content among nonwaxy landraces. This implies that two different Wx alleles regulate quantitative levels of Wx protein. Landraces with the allele for low amylose content are from Taiwan, the Philippines, Indonesia and Thailand. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

13.
用水稻抗白叶枯病基因Xa23的近等基因系CBB23与其感病轮回亲本金刚30（JG30）杂交，构建了包含2562个单株的F2作图群体。用水稻白叶枯病广致病菌系P6进行抗性鉴定表明，F2植株抗感分离比严格符合3：1。根据日本水稻基因组计划RGP水稻高密度图谱上的RFLP探针对F2群体中的145个感病单株进行RFLP检测和连锁分析，获得了6个与Xa23紧密连锁的RFLP分子标记。其中RFLP标记C1003A靠着丝粒一侧，与Xa23的遗传图距为0.4cM，为Xa23的图位克隆奠定了重要基础。并将标记C1003A成功地转化为STS标记，为分子标记辅助选择育种（MAS）提供了方便有效的分子标记。  相似文献   

14.
Functional markers reduce the risk of false selection in marker-assisted selection (MAS), and recombination between the molecular marker and the gene of interest. The present study was conducted with the objective of combining the important basmati quality traits with resistance to bacterial leaf blight (BLB) by a combination of phenotypic selection and MAS. Screening of 29 recombinants for BLB resistant genes along with aroma (fgr) gene was performed using a suite of different markers. Twenty genotypes were found in homozygous condition for Xa21 and xa13 genes. Restriction digestion analysis with BsrI, gave nine resistant recombinants. Out of nine resistant recombinants, seven were in homozygous and two were in heterozygous conditions. Recombinants viz., IRS 5441-2-21, IRS 5441-2-79, IRS 5441-2-81, IRS 5441-2-85 and IRS 5441-2-91 possessed all the three BLB resistance genes and fgr in the homozygous condition. Recombinants with enhanced resistance to BLB, basmati quality and desirable agronomic traits were identified. This germplasm can be directly developed into commercial varieties or used as immediate potential donors of BLB resistance in basmati breeding programs.  相似文献   

15.
Salinity is a major constraint affecting rice productivity in rainfed and irrigated agro-ecosystems. Understanding salinity effects on rice production at the reproductive stage could improve adaptation for this trait. Identifying quantitative trait loci (QTLs) controlling adaptation to salinity may also accelerate breeding rice germplasm for environments prone to this stress. We used the salt tolerant landrace ‘Hasawi’ as a donor parent to generate three F2 offspring (consisting each of 500 individuals) with three African cultivars (‘NERICA-L-19’, ‘Sahel 108’ and ‘BG90-2’) used as recipient parents (RP). The F2s and F2:3s were evaluated for grain yield and other traits in saline fields. Salinity caused reduction in all measured traits across the F2-derived offspring, e.g. grain yield reduced between 65 and 73 %, but some offspring had twice the RP’s grain yield. QTL analysis revealed 75 QTLs for different traits in all 3 genetic backgrounds (GBs): 24 of them were common among all the 3 GBs while 31 were noted in 2 GBs, and 17 in one GB. ‘Hasawi’ contributed on average 49 % alleles to these QTLs. Two yield and yield related QTLs (qGY11 and qTN11) common in all 3 GBs were mapped on the same chromosomal segment suggesting these QTLs might be stable across different GBs. Four other QTLs were strongly associated with salinity tolerance with peak marker RM419, representing a potential candidate for MAS due to high LOD score and relatively large effect QTLs.  相似文献   

16.
A traditional Type 3 Basmati rice cultivar grown in India is tall and lodges even under low nitrogen fertilizer dose. In addition to lodging, it is highly susceptible to several diseases and pests including bacterial blight (BB). BB resistance genes (Xa21 and xa13) and a semidwarfing gene (sd-1) were pyramided in Type 3 Basmati from a rice cultivar PR106-P2 using marker-assisted selection (MAS). Foreground selection for BB resistance genes, Xa21 and xa13 and reduced plant height gene, sd-1 was carried on the basis of linked molecular markers pTA248, RG136 and ‘h’, respectively. The BC2F3 progenies with both the BB resistance genes were highly resistant with lower lesion length than either of the genes individually. Background profiling of the selected 16 BC2F3 progenies was done using 95 anchored SSR and 12 ISSR markers. Among the selected 16 BC2F3 progenies, 38-5-2 and 38-5-36 closely clustered along with the recipient parent Type 3 Basmati showing above 85% genetic similarity with the same. Further selection was continued till F5 generation for higher recovery for Type 3 Basmati characteristics. The desirable alleles of intermediate amylose content (wx) and aroma (fgr) loci of Type 3 Basmati were also tracked using the linked SSR markers. The BC2F5 pyramid lines T3-4, T3-5, T3-6 and T3-7 homozygous for the three target genes Xa21, xa13 and sd-1 from the donor parent with wx and fgr alleles of Type 3 Basmati had excellent cooking quality and strong aroma.  相似文献   

17.
不同地理来源水稻品种的SSR分子标记遗传相似性分析   总被引：4，自引：1，他引：3  
为了评价云南水稻品种与国内外水稻品种间的遗传相似性,利用48个SSR分子标记对90个来自9个不同国家的水稻品种进行遗传相似性分析,结果共检测到269个等位基因（Na）,平均每个SSR标记检测到5.604个,变幅为3~10;共检测到159.775个有效等位基因（Ne）,平均为3.329,变幅为1.578~6.090;每个SSR标记的多态性信息含量（PIC）变幅为0.366~0.836,平均为0.661。90个水稻品种间的遗传相似系数（GS）变幅为0.021~0.875,平均为0.328。90个品种在相似系数0.212处分为籼、粳两亚种类群;聚类树形图能划分品种的地理来源;亚种内,粳型品种较籼型品种的遗传相似度高。云南粳稻育成品种的遗传相似性较高,云南水稻地方品种的遗传多样性较高,应加强对云南水稻地方品种的有效保护和籼粳分化等研究。  相似文献   

18.
Bacterial blight (BB) of rice caused by X. oryzae pv. oryzae is a major production constraint in commercial hybrid rice production in the Philippines because most of the parental lines used in hybrid production do not carry resistance genes against the pathogen. In this study, three bacterial blight resistance genes, Xa4, Xa7 and Xa21, were introgressed to a temperature-sensitive genetic male sterile (TGMS1) line. A three-way cross of AR32-19-3-3/TGMS1//IRBB4/7 (PR36944) was made to produce 1,364 F2 plants carrying various combinations of Xa4, Xa7 and Xa21. Individual plants were characterized for reaction to bacterial blight PXO61 (race 1), PXO86 (race 2), PXO99 (race 6) and pollen sterility. Of 144 F2 plants demonstrating resistance against PXO61, PXO86 and PXO99, 22 exhibited highly resistant phenotypes with mean lesion lengths ranging from 0.37–2.97 cm. Analysis of disease reaction identified 20 potential TGMS F2 plants containing Xa4, Xa7 and Xa21 while 78 plants with Xa4 + Xa7. Phenotypic and polymerase chain reaction (PCR) analyses confirmed PR36944-450, PR36944-473 and PR36944-700 as homozygous for Xa7 and Xa21 and highly resistant to all three Xoo races. Fertility of PR36944-450 and PR36944-700 was restored at permissive temperature in a growth chamber. BB-resistant TGMS lines should facilitate breeding two-line hybrids in the tropics.  相似文献   

19.
A.J. Worland  E.J. Sayers  V. Korzun 《Euphytica》2001,119(1-2):157-161
A microsatellite marker WMS261 developed at I.P.K., Gatersleben,Germany, co-segregates with the semi-dwarfing gene Rht8. Screens ofover 800 wheat varieties from 20 countries show 90% carry WMS-261alleles with 165, 174 or 192 base pairs (bp). The 192bp allele diagnosticof Rht8 occurs in most screened Southern European varieties. Anallele with 165 bp occurs in the majority of CIMMYT Mexican varieties andin most varieties bred in countries that utilize CIMMYT germplasm.Agronomic studies of single chromosome recombinant line mappingpopulations segregating for WMS 261 alleles with 165, 174 or 192 bp,show compared to the 174bp allele the 192bp allele reduces height byaround 8 cm and the 165 bp allele increases height by around 3cm. Theresults indicate the importance and widespread utilization of Rht8 asa dwarfing gene in southern Europe and suggest an adaptative significanceto the height promoting 165 bp allele in CIMMYT material.  相似文献   

20.
Balloon flower (Platycodon grandiflorum A. DC) is widely distributed in South Korea and there are some local landraces that are cultivated as a vegetable crop or medicinal plant. Making use of the gene resources of wild-type and landraces is a way to increase the genetic diversity of the cultivars. However, few tools or information are available on an efficient identification system for maintaining and management of these landraces. To improve the genetic resources for balloon flower, 22 simple sequence repeat (SSR) markers, also known as microsatellite markers, were evaluated in a collection of 42 balloon flower landraces, 34 of which were from Korea and eight from China. All microsatellite markers produced the 107 alleles ranging from 2 to 10 with a mean of 4.864 alleles per each locus (NA). The values of observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 0.00 to 0.667 (mean of 0.285) and from 0.024 to 0.741 (mean of 0.416), respectively. An average value of polymorphic information contents (PIC) were 0.382 with a range of 0.023 to 0.703. Results of population structure and phylogenetic and principal coordinate analysis (PCoA) indicated that P. grandiflorum germplasm formed two largely distinct clusters according to their origins and the genetic differentiation. There was a high level of genotypic diversity at broad geographic regions between Korea and China, but the low genetic differentiation was found within the collections from Korea. The results of the genetic diversity will be useful for the selection of the parents for developing balloon flower breeding and the multi-locus SSR markers developed herein will be a valuable resource for germplasm assessments, evaluation of genetic diversity, and population genetic studies of balloon flower.  相似文献   

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