Fine mapping of the yellow seed locus in Brassica juncea L

The yellow mustard plant in Northern Shaanxi is a precious germplasm, and the yellow seed trait is controlled by a single recessive gene. In this report, amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) techniques were used to identify markers linked to the brown seed locus in an F(2) population consisting of 1258 plants. After screening 256 AFLP primer combinations and 456 pairs of SSR primers, we found 14 AFLP and 2 SSR markers that were closely linked to the brown seed locus. Among these markers, the SSR marker CB1022 showed codominant inheritance. By integrating markers previously found to be linked to the brown seed locus into the genetic map of the F(2) population, 23 markers were linked to the brown seed locus. The two closest markers, EA02MC08 and P03MC08, were located on either side of the brown seed locus at a distance of 0.3 and 0.5 cM, respectively. To use the markers for the breeding of yellow-seeded mustard plants, two AFLP markers (EA06MC11 and EA08MC13) were converted into sequence-characterized amplified region (SCAR) markers, SC1 and SC2, with the latter as the codominant marker. The two SSR markers were subsequently mapped to the A9/N9 linkage group of Brassica napus L. by comparing common SSR markers with the published genetic map of B. napus. A BLAST analysis indicated that the sequences of seven markers showed good colinearity with those of Arabidopsis chromosome 3 and that the homolog of the brown seed locus might exist between At3g14120 and At3g29615 on this same chromosome. To develop closer markers, we could make use of the sequence information of this region to design primers for future studies. Regardless, the close markers obtained in the present study will lay a solid foundation for cloning the yellow seed gene using a map-based cloning strategy.     

甘蓝型油菜花瓣缺失基因的图谱定位

在无花瓣品系APT02和正常有花瓣品种中双4号构建的的F2分离群体中,运用AFLP和SRAP两种标记技术对甘蓝型油菜花瓣缺失基因进行分子标记和图谱定位。在两亲本间筛选20对AFLP引物和170对SRAP 引物,进一步通过BSA法筛选,获得了与甘蓝型油菜花瓣缺失基因WHB连锁的1个SRAP标记e8m3_4（600bp）和1个AFLP标记E3247_15（150bp）,标记与基因WHB之间的遗传距离分别为5 cM和13.5cM;构建了一个甘蓝型油菜(Brassica napus.L )的分子标记遗传连锁图谱,该图谱共包含213个AFLP标记、56个SRAP标记和1个形态标记,分布于17个主要连锁群、两个三联体和4个连锁对中,遗传图距总长2487.1cM,标记间平均距离为10.09 cM。通过图谱定位,控制花瓣缺失性状的基因WHB被定位到第4连锁群(LG4)上。     

Inheritance of seed colour and identification of RAPD and AFLP markers linked to the seed colour gene in rapeseed (Brassica napus L.)

In China Polima cytoplasmic male sterility (cms) is currently the most important hybrid system used for the breeding of hybrids. In an effort to develop yellow-seeded Polima cms restorer lines, we used yellow-seeded, doubled haploid (DH) line No.2127-17 as the gene source in crosses with two elite black-seeded Polima cms R lines, Hui5148-2 and 99Yu42, which originated from our breeding programme. The inheritance of seed colour was investigated in the F₂, BC₁ and F₁-derived DH progenies of the two crosses. Seed colour was found to be under the control of the maternal genotype and the yellow seed trait to be partially dominant over the black seed trait. Segregation analysis revealed a single gene locus for the partial dominance of yellow seed colour. Of 810 randomly amplified polymorphic DNA (RAPD) primers, 240 (29.6%) revealed polymorphisms between the parents. Of the 240 RAPD primers and 512 amplified fragment length polymorphism (AFLP) primer pairs, four RAPDs and 16 AFLP pairs showed polymorphisms between the bulks, with two RAPD and eight AFLP markers being identified in the vicinity of the seed-coat colour gene locus using a DH progeny population—derived from the cross Hui5148-2×No.2127-17—of 127 individuals in combination with the bulked segregant analysis strategy. Seven of these latter ten markers were linked to the allele for yellow seed, whereas the other three were linked to the allele for black seed. The seed-coat colour gene locus was bracketed by two tightly linked markers, EA02MG08 (2.4 cM) and S1129 (3.9 cM). The partial dominance and single gene control of the yellow seed-coat colour trait together with the available molecular markers will greatly facilitate the future breeding of yellow-seeded hybrid varieties.     

Inheritance of seed coat color genes in <Emphasis Type="Italic">Brassica napus</Emphasis> (L.) and tagging the genes using SRAP,SCAR and SNP molecular markers

Seed coat color inheritance in Brassica napus was studied in F₁, F₂, F₃ and backcross progenies from crosses of five black seeded varieties/lines to three pure breeding yellow seeded lines. Maternal inheritance was observed for seed coat color in B. napus, but a pollen effect was also found when yellow seeded lines were used as the female parent. Seed coat color segregated from black to dark brown, light brown, dark yellow, light yellow, and yellow. Seed coat color was found to be controlled by three genes, the first two genes were responsible for black/brown seed coat color and the third gene was responsible for dark/light yellow seed coat color in B. napus. All three seed coat color alleles were dominant over yellow color alleles at all three loci. Sequence related amplified polymorphism (SRAP) was used for the development of molecular markers co-segregating with the seed coat color genes. A SRAP marker (SA12BG18388) tightly linked to one of the black/brown seed coat color genes was identified in the F₂ and backcross populations. This marker was found to be anchored on linkage group A9/N9 of the A-genome of B. napus. This SRAP marker was converted into sequence-characterized amplification region (SCAR) markers using chromosome-walking technology. A second SRAP marker (SA7BG29245), very close to another black/brown seed coat color gene, was identified from a high density genetic map developed in our laboratory using primer walking from an anchoring marker. The marker was located on linkage group C3/N13 of the C-genome of B. napus. This marker also co-segregated with the black/brown seed coat color gene in B. rapa. Based on the sequence information of the flanking sequences, 24 single nucleotide polymorphisms (SNPs) were identified between the yellow seeded and black/brown seeded lines. SNP detection and genotyping clearly differentiated the black/brown seeded plants from dark/light/yellow-seeded plants and also differentiated between homozygous (Y2Y2) and heterozygous (Y2y2) black/brown seeded plants. A total of 768 SRAP primer pair combinations were screened in dark/light yellow seed coat color plants and a close marker (DC1GA27197) linked to the dark/light yellow seed coat color gene was developed. These three markers linked to the three different yellow seed coat color genes in B. napus can be used to screen for yellow seeded lines in canola/rapeseed breeding programs.     

Molecular mapping of the rf1 gene for pollen fertility restoration in sorghum (Sorghum bicolor L.)

We report the molecular mapping of a gene for pollen fertility in A1 (milo) type cytoplasm of sorghum using AFLP and SSR marker analysis. DNA from an F₂ population comprised of 84 individuals was screened with AFLP genetic markers to detect polymorphic DNAs linked to fertility restoration. Fifteen AFLP markers were linked to fertility restoration from the initial screening with 49 unique AFLP primer combinations (+3/+3 selective bases). As many of these AFLP markers had been previously mapped to a high-density genetic map of sorghum, the target gene (rf1) could be mapped to linkage group H. Confirmation of the map location of rf1 was obtained by demonstrating that additional linkage group-H markers (SSR, STS, AFLP) were linked to fertility restoration. The closest marker, AFLP Xtxa2582, mapped within 2.4 cM of the target loci while two SSRs, Xtxp18 and Xtxp250, flanked the rf1 locus at 12 cM and 10.8 cM, respectively. The availability of molecular markers will facilitate the selection of pollen fertility restoration in sorghum inbred-line development and provide the foundation for map-based gene isolation. Received: 22 August 2000 / Accepted: 18 October 2000     

An expanded genetic linkage map of Prunus based on an interspecific cross between almond and peach.

The genetic linkage map of Prunus constructed earlier and based on an interspecific F2 population resulting from a cross between almond (Prunus dulcis D.A. Webb) and peach (Prunus persica L. Batsch) was extended to include 8 isozyme loci, 102 peach mesocarp cDNAs, 11 plum genomic clones, 19 almond genomic clones, 7 resistance gene analogs (RGAs), 1 RGA-related sequence marker, 4 morphological trait loci, 3 genes with known function, 4 simple sequence repeat (SSR) loci, 1 RAPD, and 1 cleaved amplified polymorphic sequence (CAP) marker. This map contains 161 markers placed in eight linkage groups that correspond to the basic chromosome number of the genus (x = n = 8) with a map distance of 1144 centimorgans (cM) and an average marker density of 6.8 cM. Four more trait loci (Y, Pcp, D, and SK) and one isozyme locus (Mdh1) were assigned to linkage groups based on known associations with linked markers. The linkage group identification numbers correspond to those for maps published by the Arús group in Spain and the Dirlewanger group in France. Forty-five percent of the loci showed segregation distortion most likely owing to the interspecific nature of the cross and mating system differences between almond (obligate outcrosser) and peach (selfer). The Cat1 locus, known to be linked to the D locus controlling fruit acidity, was mapped to linkage group 5. A gene or genes controlling polycarpel fruit development was placed on linkage group 3, and control of senesced leaf color (in late fall season) (LFCLR) was mapped to linkage group 1 at a putative location similar to where the Y locus has also been placed.     

A first linkage map of olive (Olea europaea L.) cultivars using RAPD,AFLP, RFLP and SSR markers

The first linkage map of the olive (Olea europaea L.) genome has been constructed using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphisms (AFLP) as dominant markers and a few restriction fragment length polymorphisms (RFLP) and simple-sequence repeats (SSR) as codominant markers. Ninety-five individuals of a cross progeny derived from two highly heterozygous olive cultivars, Leccino and Dolce Agogia, were used by applying the pseudo test-cross strategy. From 61 RAPD primers 279 markers were obtained - 158 were scored for Leccino and 121 for Dolce Agogia. Twenty-one AFLP primer combinations gave 304 useful markers - 160 heterozygous in Leccino and 144 heterozygous in Dolce Agogia. In the Leccino map 249 markers (110 RAPD, 127 AFLP, 8 RFLP and 3 SSR) were linked. This resulted in 22 major linkage groups and 17 minor groups with fewer than four markers. In the Dolce Agogia map, 236 markers (93 RAPD, 133 AFLP, 6 RFLP and 4 SSR) were linked; 27 major linkage groups and three minor groups were obtained. Codominant RFLPs and SSRs, as well as few RAPDs in heteroduplex configuration, were used to establish homologies between linkage groups of both parents. The total distance covered was 2,765 cM and 2,445 cM in the Leccino and Dolce Agogia maps, respectively. The mean map distance between adjacent markers was 13.2 cM in Leccino and 11.9 cM in Dolce Agogia, respectively. Both AFLP and RAPD markers were homogeneously distributed in all of the linkage groups reported. The stearoyl-ACP desaturase gene was mapped on linkage group 4 of cv. Leccino.     

甘蓝型黄籽油菜种皮色泽QTL作图

甘蓝型黄籽油菜具有低纤维、高蛋白及高含油量的优点,因而己成为广大油菜育种工作者研究的重点之一。利用甘蓝型黑籽品系油研2号作父本,计蓝型黄籽品系GH06为母本,获得132个单株的F2群体;以AFLP和SSR为主要分析方法,构建了包括164个标记的甘蓝型油菜遗传连锁图谱,其中包括125个AFLP标记、37个SSR标记及一个RAPD和一个SCAR标记,分布在19个连锁群上,覆盖油菜基因组2549．8cM,标记间平均距离15．55cM。利用多区间作图法,对种皮色泽QTL进行分析,在第5及第19连锁群上各检测到一个QTL位点,分别解释表型变异46％及30．9％。     

Genetic mapping of the evergrowing gene in peach [Prunus persica (L.) Batsch

In temperate locations, terminal apices on evergrowing (also called evergreen) peach trees keep growing in winter until killed by low temperatures, while the lateral buds go into dormancy. A recessive allele of a single gene (evergrowing or evg) controls this trait in peach. The amplified fragment length polymorphism (AFLP) technique and bulked segregant analysis were applied to construct a local genetic linkage map for the evg gene from the cross Empress op op dwarf x Evergrowing (P.I. 442380). This map, comprising nine AFLP markers and the evg locus, covers a total genetic distance of 79.3 cM. Four dominant AFLP markers (EAT/MCAC, ETT/MCCA2, EAT/MCTA, and ETT/MACC) were linked to the evg locus at distances of 1, 5.3, 6.7, and 11.7 cM, respectively. EAT/MCAC and EAT/MCTA were converted into polymorphic sequence-tagged sites. Microsatellite markers in the evg region were developed from peach bacterial artificial chromosome (BAC) clones that hybridized to the AFLP marker fragments. Using three microsatellite anchor markers (pchgms12, pchgms17, and pchgms19), the local genetic linkage map was integrated into one minor linkage group of a previously constructed peach rootstock genetic linkage map. Three AFLP markers from the rootstock genetic linkage map were found linked to the evg locus.     

Identification of two major QTL for yellow seed color in two crosses of resynthesized <Emphasis Type="Italic">Brassica napus</Emphasis> line No. 2127-17

Yellow seed color, which results from a thinner seed coat, is associated with improved feed quality of rapeseed (Brassica napus L.) meal and increased oil and protein content. As this trait follows various genetic models under different genetic backgrounds, a study was performed in two genetic backgrounds to gain a better understanding of the genetic mechanisms underlying yellow seed color. The quantitative trait locus (QTL) analysis was undertaken using two crosses, Quantum ×No. 2127-17 (HZ-1) and No. 2127-17 × 94,570 (HZ-2). In the HZ-1 population, three putative QTL were detected in linkage groups N18, N5, and N3, respectively. For all of them, yellow seed color arose from the No. 2127-17 alleles. Of these QTL, the one in linkage group N18 (Bnsc-18a) explained more than half of the phenotypic variation. In the HZ-2 population, three QTL were found in linkage groups N9, N18, and N8, respectively. Of these QTL, that in linkage group N9 (Bnsc-9a) explained more than half of the phenotypic variation, whereas the QTL Bnsc-18a had a low seed color value and explained only 9.03–11.72% of the phenotypic variation. Bulked segregant analysis (BSA) of the extremes of a BC1 population derived from the cross of No. 2127-17 × 94,570 (HZ-3) identified one major gene that was identical with the QTL Bnsc-9a detected in the HZ-2 population. The QTL Bnsc-18a was common in the HZ-1 and HZ-2 populations, and the others were population-specific. These results suggested that different black-seeded forms had different seed color genes.     

The inheritance of seed color in a resynthesizedBrassica napus line No. 2127-17 including a new epistatic locus

Yellow seed is an important trait inBrassica napus. To know the genet ic basis of yellow seed color inBrassica napus, we carried out genetic studies by using conventional genetics analyses. The conventional genetics was studied in generations (F1 F2 reciprocal F2, BC1, and F23) ofB. napus derived from crosses between a yellow-seeded (No. 2127-17) and nine different black-seeded parents. The results indicated that seed color was mainly controlled by the maternal genotype but influenced by the interact ion between the maternal and endosperm and/or embryonic genotypes. In the combinations which included black-seeded lines SW0780, 94560, 94545 and 1141B, the yellow seed is partially dominant over black with two or three dominance epistasis ratio. A dominant yellow-seeded gene Y which exhibits epistatic effects on the two independent dominant black-seeded genes B and C was ident ified in DH line No. 2127-17. These observations are in agreement with our previous reports. But in the rests, including the crosses with HS No.4, HS No. 3, XY No. 15, 94570 and ZS No. 10, the black seed color was dominant over yellow seed color. The inheritance of this trait in the segregating populations fits the model of a digenic dominance epistasis or triplicate dominance epistasis. A new locus was identified and designated as D: the dominant gene D for black seed color inhibits the dominant gene Y. Therefore, in combination with the Y, B and C, we found that the seed color was influenced by at least four genes. Identifying seed color genes and defining their inheritance should further our understanding of yellow seed color trait and facilitate development of new and better yellow-seeded cult ivars ofBrassics napus.     

家蚕黄血抑制基因的SSR定位

家蚕黄茧性状主要由3个基因控制, 分别是黄血基因(Yellow blood, Y), 黄血抑制基因(Yellow inhibitor, I)和黄茧基因(Out-layer yellow cocoon, C)。I基因阻止类胡萝卜素从中肠上皮细胞到血淋巴的转运, 是天然黄茧形成过程中的重要控制基因。利用家蚕雌性不发生交换的特点, 采用黄血黄茧品系KY和白血白茧品系巴格达特(Ba)组配正反交群体(Ba×KY)×KY和KY×(Ba×KY), 分别记作BC1F和BC1M, 根据已经构建的家蚕SSR分子标记连锁图谱对I基因进行了定位及连锁分析。筛选出3个与I基因连锁的SSR标记。BC1F群中的所有白血个体均表现出与(Ba×KY) F1相同的杂合型带型; 而所有黄血个体带型与亲本KY一致, 为纯合型。利用另一个群体BC1M构建了关于I基因的遗传连锁图, 连锁图的遗传距离为38.4 cM, 与I基因最近的引物为S0904, 图距为7.4 cM。     

QTL Mapping of Seed Coat Color for Yellow Seeded Brassica napus

The development of yellow-seeded varieties of Brassica napus for improving the oilseed quality characteristics of lower fiber content and higher protein and oil content has been a major focus of breeding researches worldwide in recent years. With the black-seeded ‘Youyan 2’ as male and the yellow-seeded GH₀₆ as female parents respectively, F₂ population of 132 individuals were obtained. A linkage map was constructed with 164 markers including 125 AFLP, 37 SSR, 1 RAPD and 1 SCAR markers distributed over 19 linkage groups covering approximately 2 549.8 cM with an average spacing of 15.55 cM. Two loci located on the 5th and 19th group were detected for the trait of seed coat color based on the linkage group using multiple interval mapping method and explained 46% and 30.9% of the phenotypic variation, respectively.     

甘蓝型油菜千粒重性状的QTL初步定位研究

千粒重是油菜重要的产量相关性状之一,构建油菜遗传连锁图谱是研究其产量性状基因的前提。本研究利用小孢子培养技术,选育出了甘蓝型油菜大粒品系(G-42)和小粒品系(7-9)的纯合DH系DH-G-42和DH-7-9,其千粒重分别为6.24 g和2.42 g,二者比值达2.58。以DH-G-42为母本、DH-7-9为父本,构建了含190个单株的F2遗传作图群体,利用SSR和SRAP标记技术绘制遗传连锁图谱,该图谱共包含20个连锁群,涉及128个SSR标记和100个SRAP标记,图谱总长1546.6cM,标记间平均图距为6.78cM。本研究共检测到3个与千粒重性状相关的QTL,分别位于A9和C1连锁群,其中qSW-A9-1和qSW-A9-2贡献率分别达到10.98%和27.45%,均可视为控制粒重的主效QTL。本研究为后续进行油菜千粒重性状QTL的精细定位分析、分子标记辅助选择育种及新基因的克隆等奠定了基础。     

Genetic linkage maps of the chromosomal regions associated with apomictic and sexual modes of reproduction in Cenchrus ciliaris

Cenchrus ciliaris reproduces by apomixis, an asexual mode of reproduction through seeds. Genetic analysis of apomixis in this species revealed that this trait is dominant and that a chromosomal region of more than 11?Mb controls this trait, which is hemizygous, heterochromatic and recombinationally suppressed. A novel F₂ mapping population comprising 86 individuals segregating for apomictic and sexual modes of reproduction, generated after crossing a new set of obligate apomictic and sexual parents (IG-96-3108 and IG-96-443), was used in this study to identify a large number of amplified fragment length polymorphism (AFLP) and sequence characterized amplified region (SCAR) markers linked to these traits. Out of 180 polymorphic AFLP markers, 42 and 29 markers associated with apomixis and sexuality were mapped around Apo and Sexual loci, respectively. Markers 20G, 18G and 19G showed close linkage to Apo locus at map distance of only 1.1?cM, while 12FS, 4HS and 12b showed tight linkage to Sexual locus at map distance of 1.7?cM. Markers clustered around Apo and Sexual loci on either side. A large number of recombining AFLP markers were mapped around both loci, indicating a minor role of suppression of recombination. Four anchor markers from earlier studies also clustered around Apo locus, validating the present genetic linkage map. In addition, seven and one SCAR markers closely linked to Apo and Sexual loci were also developed, which could be used for fine mapping of the loci.     

High-density linkage mapping revealed suppression of recombination at the sex determination locus in papaya

A high-density genetic map of papaya (Carica papaya L.) was constructed using 54 F(2) plants derived from cultivars Kapoho and SunUp with 1501 markers, including 1498 amplified fragment length polymorphism (AFLP) markers, the papaya ringspot virus coat protein marker, morphological sex type, and fruit flesh color. These markers were mapped into 12 linkage groups at a LOD score of 5.0 and recombination frequency of 0.25. The 12 major linkage groups covered a total length of 3294.2 cM, with an average distance of 2.2 cM between adjacent markers. This map revealed severe suppression of recombination around the sex determination locus with a total of 225 markers cosegregating with sex types. The cytosine bases were highly methylated in this region on the basis of the distribution of methylation-sensitive and -insensitive markers. This high-density genetic map is essential for cloning of specific genes of interest such as the sex determination gene and for the integration of genetic and physical maps of papaya.     

A genetic linkage map based on AFLP and SSR markers and mapping of QTL for dry-matter content in sweetpotato

We developed a genetic linkage map of sweetpotato using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers and a mapping population consisting of 202 individuals derived from a broad cross between Xushu 18 and Xu 781, and mapped quantitative trait loci (QTL) for the storage root dry-matter content. The linkage map for Xushu 18 included 90 linkage groups with 2077 markers (1936 AFLP and 141 SSR) and covered 8,184.5 cM with an average marker distance of 3.9 cM, and the map for Xu 781 contained 90 linkage groups with 1954 markers (1824 AFLP and 130 SSR) and covered 8,151.7 cM with an average marker distance of 4.2 cM. The maps described herein have the best coverage of the sweetpotato genome and the highest marker density reported to date. These are the first maps developed that have 90 complete linkage groups, which is in agreement with the actual number of chromosomes. Duplex and triplex markers were used to detect the homologous groups, and 13 and 14 homologous groups were identified in Xushu 18 and Xu 781 maps, respectively. Interval mapping was performed first and, subsequently, a multiple QTL model was used to refine the position and magnitude of the QTL. A total of 27 QTL for dry-matter content were mapped, explaining 9.0–45.1 % of the variation; 77.8 % of the QTL had a positive effect on the variation. This work represents an important step forward in genomics and marker-assisted breeding of sweetpotato.     

A molecular genetic map and electrophoretic karyotype of the plant pathogenic fungus Cochliobolus sativus

A molecular genetic map was constructed and an electrophoretic karyotype was resolved for Cochliobolus sativus, the causal agent of spot blotch of barley and wheat. The genetic map consists of 27 linkage groups with 97 amplified fragment length polymorphism (AFLP) markers, 31 restriction fragment length polymorphism (RFLP) markers, two polymerase chain reaction amplified markers, the mating type locus (CsMAT), and a gene (VHv1) conditioning high virulence on barley cv. Bowman. These linkage groups covered a map distance of 849 cM. The virulence gene VHv1 cosegregated with six AFLP markers and was mapped on one of the major linkage groups. Fifteen chromosome-sized DNAs were resolved in C. sativus isolates ND93-1 and ND9OPr with contour-clamped homogeneous electric field (CHEF) electrophoresis combined with telomere probe analysis of comigrating chromosome-sized DNAs. The chromosome sizes ranged from 1.25 to 3.80 Mbp, and the genome size of the fungus was estimated to be approximately 33 Mbp. By hybridizing genetically mapped RFLP and AFLP markers to CHEF blots, 25 of the 27 linkage groups were assigned to specific chromosomes. The barley-specific virulence locus VHv1 was localized on a chromosome of 2.80 Mbp from isolate ND9OPr in the CHEF gel. The total map length of the fungus was estimated to be at least 1,329 cM based on the map distance covered by the linked markers and the estimated gaps. Therefore, the physical to genetic distance ratio is approximately 25 kb/cM. Construction of a high-resolution map around target loci will facilitate the cloning of the genes conferring virulence and other characters in C. sativus by a map-based cloning strategy.     

花椰菜遗传图谱的构建及NBS-LRR类抗性同源基因在图谱中的定位

利用AFLP和NBS profiling技术, 以花椰菜自交系“AD白花”与高代自交不亲和系“C-8”杂交得到的F1代自交产生的F2代分离群体为材料, 构建了第一个花椰菜遗传连锁图谱。该图谱由234个AFLP标记和21个NBS标记构成了9个连锁群, 总图距为668.4 cM, 标记间平均距离为2.9 cM。每个连锁群包含的位点数从12到47个, 相邻两标记之间的距离范围是0~14.9 cM。NBS标记分布在8个连锁群中, 这些标记大部分聚在一起。本研究为今后的基因定位及重要农艺性状的分析提供框架图。此外, 研究NBS profiling 方法在花椰菜中的稳定性和有效性以及NBS-LRR类RGA在花椰菜基因组中的分布和特点。     

用AFLP标记快速构建遗传连锁图谱并定位一个新基因tms5

报导了一个分子标记连锁图的快速构建方法。通过对水稻(Oryza sativa L．)“安农S-1”和“南京11”的F2分离群体的AFLP分析找到了142个AFLP标记,用这142个AFLP标记以及已定位的25个SSR标记和5个RFIP标记构建了水稻12个染色体的分子标记连锁图,该图覆盖水稻基因组的1537．4cM,相邻标记间的平均间距为9．0cM,这是在国内建立的第一张AFLP标记连锁图。在建立连锁图谱的同时把一个新基因tms5(水稻温敏核不育基因)定位在第2染色体上。