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1.
Two related segregating populations of Theobroma cacao L. were analysed for their resistance to Phytophthora palmivora. The first F1 population was obtained by crossing two susceptible cacao clones of Catongo (a highly homozygous genotype) and Pound 12(a
highly heterozygous genotype) and the second population was obtained by backcrossing a single F1 tree with Catongo. The genetic maps obtained for each population were compared. The F1 map includes 162 loci and the backcross has 140 loci. The two maps, F1 and BC1, exhibit high co-linear loci organization covering respectively, 772 and 944 cM.Phytophthora resistance was assessed by measuring the size increase of a lesion at five (DL5)and ten days (DL10) after pod inoculation.
Six different QTL were detected in the F1 and BC1 populations. One QTL was found in both populations, and appeared to be a major component of disease resistance, and explaining
nearly 48% of the phenotypic variance in the F1 population. The absence of some yield QTL detection in the BC1 in comparison with the F1 population is due to the lack of transmission of the favouring alleles for these QTL from the single F1 tree used for the backcross. The phenotypic variance explained by the action of the quantitative trait alleles indicated
that genetic factors of both major and minor effects were involved in the control of the character studied. QTL conferring
increased resistance to Phytophthorawere identified in both susceptible parents, suggesting the presence of transgressive traits and the possibility of selection
in cacao. Pleiotropic and epistatic effects for the QTL were also detected. Finally, the use of marker assisted selection
(MAS) in cacao breeding programs is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
A program was initiated in 1994 to compare the efficiency of marker-assisted selection (MAS) and conventional phenotypic selection.
A population of 300 F3:4 families was generated from the cross between two maize inbred lines F2 and F252 and selected on an index combining grain yield and grain moisture at harvest. This population was characterised for 93 RFLP
markers and evaluated as testcrosses in a large range of environments. Three methods of selection were applied (i) two cycles
of conventional phenotypic selection; (ii) two cycles of MAS based on an index combining phenotypic values and QTL genetic
values and (iii) one cycle of combined MAS followed by two cycles of selection based only on the QTL effects estimated in
the first generation. The different populations were characterised for RFLP markers. The evolution of allele frequencies showed
that selection on only-markers was very efficient for fixing QTL alleles found favourable in the initial population. This
evolution was quite different from that observed for phenotypic selection or combined MAS. Genetic gain was evaluated and
found significant for each method of selection. Nevertheless, the difference between phenotypic selection and combined MAS
was not significant. The two additional cycles of MAS on only-markers did not improve significantly the genetic value of the
population. Moreover, the genetic variance of this population remained high, despite most of the QTL initially detected were
almost fixed. The results suggest that the QTL effects estimated in the initial population were not stable due to epistasis
and/or QTL by environment interactions.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Suitability of wheat (Triticum aestivum L.) for many food products depends on its unique protein. Elevated grain protein content (GPC) and its quality influences
the bread making properties of wheat. The objective of this study was to examine the association of elevated GPC with agronomic
and end-use quality in two hard red spring wheat recombinant inbred (RI) populations derived from wild emmer (Triticum turgidum L. var. dicoccoides). The two hard red spring populations (ND683/Bergen and Glupro/Bergen) were developed using a single-seed-descent method.
ND683 and ‘Glupro’ are high in GPC (180 g kg-1), presumably due to the introgression of gene(s) from Triticum turgidum L. var. dicoccoides and ‘Bergen’ is low in GPC (145 g kg-1). From each of the two populations 12 high- and 12 low-GPC RI lines (F5:7) were selected for replicated testing at two North Dakota (ND) locations in 1995. In both populations, the high-GPC lines
had significantly (p < 0.05) higher values compared to the low-GPC lines for mean GPC and water absorption. Mean grain yield of the high-GPC lines
was not significantly different from the low-GPC lines in both populations. In the ND683/Bergen population, the high-GPC lines
had significantly (p < 0.05) higher values than the low-GPC lines for mean plant height, days to heading, and flour extraction. GPC was significantly
(p < 0.05)and negatively associated with test weight and also significantly (p < 0.01) and positively associated with water absorption in the Glupro/Bergen population. In these populations, results suggested
that it may be possible to select lines that combine higher GPC and acceptable yield level, but later in maturity and taller
in plant height.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
Kuljit Kaur Cheema Navtej S. Bains Gurjit S. Mangat Aparna Das Yogesh Vikal Darshan S. Brar Gurdev S. Khush Kuldeep Singh 《Euphytica》2008,160(3):401-409
Modern rice varieties that ushered in the green revolution brought about dramatic increase in rice production worldwide but
at the cost of genetic diversity at the farmers’ fields. The wild species germplasm can be used for broadening the genetic
base and improving productivity. Mining of alleles at productivity QTL from related wild species under simultaneous backcrossing
and evaluation, accompanied by molecular marker analysis has emerged as an effective plant breeding strategy for utilization
of wild species germplasm. In the present study, a limited backcross strategy was used to introgress QTL associated with yield
and yield components from Oryza rufipogon (acc. IRGC 105491) to cultivated rice, O. sativa cv IR64. A set of 12 BC2F6 progenies, selected from among more than 100 BC2F5 progenies were evaluated for yield and yield components. For plant height, days to 50% flowering and tillers/plant, the introgression
lines did not show any significant change compared to the recurrent parent IR64. For yield, 9 of the 12 introgression lines
showed significantly higher yield (19–38%) than the recurrent parent IR64. Four of these lines originating from a common lineage
showed higher yield due to increase in grain weight and another three also from a common lineage showed yield increase due
to increase in grain number per panicle. For analyzing the introgression at molecular level all the 12 lines were analyzed
for 259 polymorphic SSR markers. Of the total 259 SSR markers analyzed, only 18 (7.0%) showed introgression from O. rufipogon for chromosomes 1, 2, 3, 5, 6 and 11. Graphical genotypes have been prepared for each line and association between the introgression
regions and the traits that increased yield is reported. Based on marker trait association it appears that some of the QTL
are stable across the environments and genetic backgrounds and can be exploited universally. 相似文献
5.
Kun-Pu Zhang Guang-Feng Chen Liang Zhao Bin Liu Xian-Bin Xu Ji-Chun Tian 《Euphytica》2009,165(3):471-484
Flour color is an important trait in the assessment of flour quality for the production of many end products. In this study,
quantitative trait loci (QTLs) with additive effects, epistatic effects, and QTL × environment (QE) interactions for flour
color in bread wheat (Triticum aestivum L.) were studied, using a set of 168 doubled haploid (DH) lines derived from a Huapei 3 × Yumai 57 cross. A genetic map was
constructed using 283 simple sequence repeats (SSR) and 22 expressed sequence tags (EST)-SSR markers. The DH and parents were
evaluated for flour color in three environments. QTL analyses were performed using QTLNetwork 2.0 software based on a mixed
linear model approach. A total of 18 additive QTLs and 24 pairs of epistatic QTLs were detected for flour color, which were
distributed on 19 of the 21 chromosomes. One major QTL, qa1B, closely linked to barc372 0.1 cM, could account for 25.64% of the phenotypic variation of a* without any influence from the environments. So qa1B could be used in the molecular marker-assisted selection (MAS) in wheat breeding programs. The results showed that both additive
and epistatic effects were important genetic basis for flour color, and were also sometimes subject to environmental modifications.
The information obtained in this study should be useful for manipulating the QTLs for flour color by MAS in wheat breeding
programs.
Kun-Pu Zhang and Guang-Feng Chen contributed equally to this study. 相似文献
6.
Summary Two RAPD markers linked to gene for resistance (assayed as pustule number cm−2 leaf area) to rust [Uromyces fabae (Pers.) de Bary] in pea (Pisum sativum L.) were identified using a mapping population of 31 BC1F1 [HUVP 1 (HUVP 1 × FC 1] plants, FC 1 being the resistant parent. The analysis of genetics of rust resistance was based on
the parents, F1, F2, BC1F1 and BC1F2 generations. Rust resistance in pea is of non-hypersensitive type; it appeared to be governed by a single partially dominant
gene for which symbol Ruf is proposed. Further, this trait seems to be affected by some polygenes in addition to the proposed oligogene Ruf. A total of 614 decamer primers were used to survey the parental polymorphism with regard to DNA amplification by polymerase
chain reaction. The primers that amplified polymorphic bands present in the resistant parent (FC 1) were used for bulked segregant
analysis. Those markers that amplified consistently and differentially in the resistant and susceptible bulks were separately
tested with the 31 BC1F1 individuals. Two RAPD makers, viz., SC10-82360 (primer, GCCGTGAAGT), and SCRI-711000 (primer, GTGGCGTAGT), flanking the rust resistance gene (Ruf) with a distance of 10.8 cM (0.097 rF and LOD of 5.05) and 24.5 cM (0.194 rF and a LOD of 2.72), respectively, were identified.
These RAPD markers were not close enough to Ruf to allow a dependable maker-assisted selection for rust resistance. However, if the two makers flanking Ruf were used together, the effectiveness of MAS would be improved considerably. 相似文献
7.
Mingming Sun Lirui Cheng Caihong Jiang Chengguang Zhu Min Ren Yusheng Zhang Yu Zhang Dan Liu Qiang Zhao Ruimei Geng Xiaoli Hu Aiguo Yang Yuanying Wang 《Euphytica》2018,214(10):195
Brown spot (BS) is a destructive foliar disease in tobacco (Nicotiana tabacum L.) and is caused by Alternaria alternata. BS poses a serious threat to tobacco production worldwide. To develop molecular markers that are tightly linked to BS resistance for marker-assisted selection (MAS), F2, F2:3 and BC3F2:3 populations were developed from a cross between a source of BS resistance Jingyehuang (JYH) and a BS susceptible flue-cured variety NC82. One hundred eighty-one F2 individuals, 180 F2:3 lines and 256 BC3F2:3 lines were evaluated for field resistance under different environments and quantitative trait loci (QTL) were identified by linkage mapping. A major QTL was mapped on chromosome15; this QTL explained 8.6–18.0% of the phenotypic variation under different conditions. Furthermore, 219 accessions were evaluated for their responses to BS at two sites, and association mapping (AM) was used to verify the chromosomal region harboring the major QTL. The AM results showed that six significant marker-trait associations were detected at two sites. Among these markers, the marker Indel53 within the specific chromosomal region exhibited the most significant association with resistance to BS and explained 20.0 and 21.5% of the phenotypic variation at the two sites, respectively. An approximately 2-Mb physical interval at the locus of marker Indel53 contained 31 predicted genes; quantitative real-time PCR results suggested that two of these genes (Nitab 4.5_0000264g0050.1 and Nitab 4.5_0000264g0130.1) were probable candidate genes for resistance to BS. In summary, our results suggested that the novel major QTL from tobacco variety JYH for resistance to BS provided partial effective resistance against A. alternata and was useful for MAS of resistance to BS in tobacco breeding. 相似文献
8.
Root traits are key components of plant adaptation to drought environment. By using a 120 recombined inbred lines (RILs) rice
population derived from a cross between IRAT109, a japonica upland rice cultivar and Yuefu, a japonica lowland rice cultivar, a complete genetic linkage map with 201 molecular markers covering 1,833.8 cM was constructed and
quantitative trait loci (QTLs) associated with basal root thickness (BRT) were identified. A major QTL, conferring thicker
BRT, located on chromosome 4, designated brt4, explained phenotypic variance of 20.6%, was selected as target QTL to study the effects of marker-assisted selection (MAS)
using two early segregating populations derived from crosses between IRAT109 and two lowland rice cultivars. The results showed
that the flanking markers of brt4 were genetically stable in populations with different genetic backgrounds. In the two populations under upland conditions,
the difference between the means of BRT of plants carrying positive and negative favorable alleles at brt4 flanking markers loci was significant. Phenotypic effects of BRT QTL brt4 were 5.05–8.16%. When selected plants for two generations were planted at Beijing and Hainan locations under upland conditions,
MAS effects for BRT QTL brt4 were 4.56–18.56% and 15.46–26.52% respectively. The means of BRT for the homozygous plants were greater than that of heterozygous
plants. This major QTL might be useful for rice drought tolerance breeding.
L. Liu and P. Mu are contributed equally to this work. 相似文献
9.
Summary
Aegilops umbellulata acc. Y39 and Triticum carthlicum acc. PS5, immune to many powdery mildew isolates, were crossed to make an amphidiploid line Am9. The powdery mildew resistance of Am9 was transferred to common wheat cultivar Laizhou953 by crossing and backcrossing. In this study, the origin of powdery mildew resistance in a BC3F4:5 population derived from a cross of Am9 and Laizhou953 was identified. Microsatellite markers analysis showed that markers Xgwm257, Xgwm296, and Xgwm319, co-segregated with the powdery mildew resistance, whereas markers Xgwm210, Xgwm388/140, Xgwm388/170 and Xgwm526 were related to susceptibility and linked to resistance in repulsion. Of three markers related to resistance, Xgwm257 and Xgwm319 were codominant, whereas Xgwm296 was dominant. All three markers were Ae. umbellulata-specific indicating that resistance in the test population originated from Ae. umbellulata acc. Y39. The chromosome location and mapping of these linked microsatellite markers, the chromosome numbers of derived BC3F4:6 families, and chromosome pairing in F1 plants from a cross of a homozygous resistant BC3F4:5 plant and Laizhou953, showed that wheat chromosome 2B was substituted by Ae. umbellulata chromosome 2U. This is the first gene conferring powdery mildew resistance transferred to wheat from Ae. umbellulata, and it should be a novel resistance gene to powdery mildew. It was temporarily designated PmY39.The first two authors made equal contributions 相似文献
10.
The pol cytoplasmic male-sterility system has been widely used as a component for utilization of heterosis in Brassica napus and offers an attractive system for study on nuclear–mitochondrial interactions in plants. Genetic analyses have indicated
that one dominant gene, Rfp, was required to achieve complete fertility restoration. As a first step toward cloning of this restorer gene, we attempted
molecular mapping of the Rfp locus using the amplified fragment length polymorphism (AFLP) technique combined with bulked segregant analysis (BSA) method.
A BC1 population segregating for Rfp gene was used for tagging. From the survey of 1,024 AFLP primer combinations, 13 linked AFLP markers were obtained and five
of them were successfully converted into sequence characterized amplified region (SCAR) markers. A population of 193 plants
was screened using these markers and the closest AFLP markers flanking Rfp were at the distances of 2.0 and 5.3 cM away, respectively. Further the AFLP or SCAR markers linked to the Rfp gene were integrated to one doubled-haploid (DH) population derived from the cross Quantum × No.2127-17 available in our
laboratory, and Rfp gene was mapped on N18, which was the same as the previous report. These molecular markers will facilitate the marker-assisted
selection (MAS) of pol CMS restorer lines. 相似文献
11.
利用染色体片段代换系定位陆地棉株高QTL 总被引:4,自引:0,他引:4
以陆地棉中棉所36为轮回亲本和海岛棉海1为供体亲本, 构建染色体片段代换系。为了能检测到稳定的株高QTL,将三个代换系群体(BC5F3, BC5F3:4和BC5F3:5)在5个环境中种植,2009年和2010年分别在河南安阳种植BC5F3单株、BC5F3:4株行, 2011年分别在河南安阳、辽宁辽阳和新疆石河子种植BC5F3:4株系。结果表明,在不同群体环境中株高的超亲比例为53.43%~88.97%。从早期构建的总图距为5088.28 cM, 含有2280个SSR标记位点,覆盖26条染色体的遗传连锁图谱中筛选标记,对408个单株进行的SSR鉴定,结果检测到16个株高QTL,分布在10条染色体上。单个QTL解释的表型变异为7.35%~13.17%。有7个QTL在2个以上环境被检测到。与标记MUSS563紧密连锁的qPH-15-19在一个环境中被检测到,在前人的研究中也有报道。这些结果为进一步精细定位QTL、基因克隆、分子辅助选择等研究奠定基础。 相似文献
12.
Jing Li Peng Xu Xianneng Deng Jiawu Zhou Fengyi Hu Jianmin Wan Dayun Tao 《Euphytica》2008,164(3):699-708
To further understand the nature of hybrid sterility between Oryza sativa and Oryza glaberrima, quantitative trait loci (QTL) controlling hybrid sterility between the two cultivated rice species were detected in BC1F1 and advanced backcross populations. A genetic map was constructed using the BC1F1 population derived from a cross between WAB450-16, an O. sativa cultivar, and CG14, an O. glaberrima cultivar. Seven main-effect QTLs for pollen and spikelet sterility were detected in the BC1F1. Forty-four sterility NILs (BC6F1) were developed via successive backcrosses using pollen sterility plants as female and WAB450-16 as the recurrent parent.
Seven NILs, in which the target QTL regions were heterozygous while the other QTL regions as well as most of the reminder
of the genome were homozygous for the WAB450-16 allele, were selected as the QTL identification materials. BC7F1 for the seven NILs showed a continuous variation in pollen and spikelet fertility. The four identified pollen sterility QTLs
were located one each on chromosomes 1, 3, 7 and 7. Pollen sterility loci qSS-3 and qSS-7a were on chromosomes 3 and 7, respectively, which coincides with the previously identified S19, and S20, while loci qSS-1 and qSS-7b on chromosomes 1 and 7L appear distinct from all previously reported loci. An epistatic interaction controlling the hybrid
sterility was detected between qSS-1 and qSS-7a. 相似文献
13.
Grain protein concentration (GPC) is an important quality factor in durum wheat [Triticum turgidum (L.) var. durum]. Due to the strong environmental influence on GPC, molecular markers linked to quantitative trait loci (QTL) affecting GPC have the potential to be valuable in wheat breeding programs. Various quantitative traits in a population of 133 recombinant inbred chromosome lines were studied in replicated trials at three locations in North Dakota. Segregation for GPC, 1000-kernel weight, gluten strength, heading date, and plant height was observed. By relating phenotypic data to a linkage map obtained from the same population, three QTL affecting GPC, and one affecting yield were identified. The genotypic coefficients of determination for both traits were high. 相似文献
14.
QTL mapping of fiber quality in an elite hybrid
derived-RIL population of upland cotton 总被引:15,自引:0,他引:15
Baohua Wang Wangzhen Guo Xiefei Zhu Yaoting Wu Naitai Huang Tianzhen Zhang 《Euphytica》2006,152(3):367-378
Xiangzamian 2 (XZM2) was the most widely cultivated cotton hybrid planted as F1 hybrids and as selfed F2 seeds in China before the release of transgenic Bt hybrids. By crossing two parents of XZM2, Gossypium hirsutum cv. Zhongmiansuo12 (ZMS12) and G. hirsutum acc. 8891, and through subsequent selfings, we obtained F8 and F9 populations of 180 recombinant inbred lines (RILs). A RIL population was cultivated in two cotton-growing regions in China for 2 years. The purpose of the present research was to detect quantitative trait loci (QTL) for fiber quality and provide information applicable to cotton breeding. A genetic map was constructed mainly using SSR markers. QTL controlling fiber quality traits were determined at the single-locus and two-locus levels, and genotype-by-environment interactions were analyzed. Among the main-effect QTL, a fiber length QTL qFL-D2-1 and a reflectance QTL qFR-D2-1 were simultaneously detected at two growing regions in 2 years, which suggested a high degree of stability in different environments, and might be of particular value for a marker-assisted selection (MAS) program. The results suggested that epistatic effects, as well as additive effects, of QTL play important roles in fiber quality in these RILs. In our research, the phenomenon of QTL clusters was detected in the cotton genome. 相似文献
15.
Hidetoshi Ajisaka Yasuhisa Kuginuki Susumu Yui Sueo Enomoto Masashi Hirai 《Euphytica》2001,118(1):75-81
DNA markers linked to a locus controlling an extreme late bolting trait, which was originally found in a local cultivar of
a non-heading leafy vegetable,‘Osaka Shirona Bansei’ (Brassica rapa L. ssp. pekinensis syn. campestris L.) were identified using bulked segregant analysis. A doubled haploid (DH) line, DH27, which is a progeny of ‘Osaka Shirona
Bansei’, shows extreme late bolting, and bolts without vernalization. DH27 was crossed with a normal bolting DH line, G309.
The plantlets of the parents, F1 and F2, were vernalized and then grown in a greenhouse. The bolting time of F2 plants showed a continuous distribution from 19 to 231 days after vernalization (DAV), suggesting the effects of a few major
genes and polygenes. Possible linkage markers for this trait were screened by modified bulked segregant analysis (BSA). The
BSA using four bulks suggested that a 530-bp RAPD band RA1255C was linked to a locus controlling the bolting trait. The RAPD
band was cloned and used as a probe to detect RFLP. The fragment detected a single locus, BN007-1,the segregation of which
in the F2 population matched that of RA1255C. Three other RAPDs were found to be linked to BN007-1. A quantitative trait locus(QTL)
affecting the bolting time was detected around BN007-1 using MAPMAKER/QTL. Since the difference between bolting times of both
the parental genotypes in the F2 was 138 days, these markers may be useful for a marker-assisted selection (MAS) in the breeding program for late bolting
or bolting-resistant cultivars in B. rapa crops.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Validation of a major QTL for scab resistance with SSR markers and use of marker-assisted selection in wheat 总被引:10,自引:1,他引:10
The objectives of this study were to validate the major quantitative trait locus (QTL) for scab resistance on the short arm of chromosome 3B in bread wheat and to isolate near‐isogenic lines for this QTL using marker‐assisted selection (MAS). Two resistant by susceptible populations, both using ‘Ning7840’ as the source of resistance, were developed to examine the effect of the 3BS QTL in different genetic backgrounds. Data for scab resistance and simple sequence repeat (SSR) markers linked to the resistance QTL were analyzed in the F2:3 lines of one population and in the F3:4 lines of the other. Markers linked to the major QTL on chromosome 3BS in the original mapping population (‘Ning7840’/‘Clark’) were closely associated with scab resistance in both validation populations. Marker‐assisted selection for the QTL with the SSR markers combined with phenotypic selection was more effective than selection based solely on phenotypic evaluation in early generations. Marker‐assisted selection of the major QTL during the seedling stage plus phenotypic selection after flowering effectively identified scab resistant lines in this experiment. Near‐isogenic lines for this 3BS QTL were isolated from the F6 generation of the cross ‘Ning7840’/‘IL89‐7978’ based on two flanking SSR markers, Xgwm389 and Xbarc147. Based on these results, MAS for the major scab resistance QTL can improve selection efficiency and may facilitate stacking of scab resistance genes from different sources. 相似文献
17.
Molecular mapping and identification of QTL's associated to oat crown rust partial resistance 总被引:1,自引:0,他引:1
Marta M. Barbosa Luiz C. Federizzi Sandra C. K. Milach José A. Martinelli Gladis C. Thomé 《Euphytica》2006,150(1-2):257-269
Summary Molecular mapping is a promising strategy for studying and understanding traits with complex genetic control, such as partial resistance to oat crown rust. The objectives of this research were to develop molecular maps from the progenies of the cross UFRGS7 (susceptible) × UFRGS910906 (partially resistant) and to identify QTLs (quantitative trait loci) associated to partial resistance to oat crown rust in two generations of that population.DNA of 86 genotypes of the F2 and 90 genotypes of the F6 UFRGS7 × UFRGS910906 population were used to generate AFLP markers. Molecular maps were constructed using Mapmaker Exp. 3.0 and QTLs for partial resistance to oat crown rust were identified with Mapmaker/QTL software. Five hundred and fifty seven markers in the F2 and 243 markers in the F6 generations were identified. The F2 map integrated 250 markers in 37 linkage groups. The F6 map integrated 86 markers in 17 linkage groups.Five QTLs were identified for partial resistance to oat crown rust in the F2 generation and three QTLs in the F6. The QTL identified on F6 through the PaaaMctt340 AFLP marker showed consistency across two environments and two generations (F4 and F6), and appear to have potential for marker-assisted selection in oat. 相似文献
18.
Heterosis is an important way to improve yield and quality for many crops. Hybrid rice and hybrid maize contributed to enhanced productivity which is essential to supply enough food for the increasing world population. The success of hybrid rice in China has led to a continuous interest in hybrid wheat, even when most research on hybrid wheat has been discontinued in other countries for various reasons including low heterosis and high seed production costs. The Timopheevii cytoplasmic male sterile system is ideal for producing hybrid wheat seeds when fertility restoration lines with strong fertility restoration ability are available. To develop PCR-based molecular markers for use in marker-assisted selection of fertility restorer lines, two F2 populations derived from crosses R18/ND36 and R9034/ND36 were used to map fertility restoration genes in the two elite fertility restorer lines (R-lines) R18 and R9034. Over 678 SSR markers were analyzed, and markers closely linked to fertility restoration genes were identified. Using SSR markers, a major fertility restoration gene, Rf3, was located on the 1B chromosome in both populations. This gene was partially dominant in conferring fertility restoration in the two restorer lines. SSR markers Xbarc207, Xgwm131, and Xbarc61 are close to this gene. These markers may be useful in marker-assisted selection of new restorer lines with T. timopheevii cytoplasm. Two minor QTL conferring fertility restoration were also identified on chromosomes 5A (in R18) and 7D (in R9034) in two R-lines. 相似文献
19.
Juthaporn Khampila Kamol Lertrat Weerasak Saksirirat Jirawat Sanitchon Nooduan Muangsan Piyada Theerakulpisut 《Euphytica》2008,164(3):615-625
Exserohilum turcicum causes northern corn leaf blight (NCLB), an important disease occurring in maize producing areas throughout the world. Currently,
the development of cultivars resistant to E. turcicum seems to be the most efficient method to control NCLB damage. Marker-assisted selection (MAS) enables breeders to improve
selection efficiency. The objective of this work was to identify random amplified polymorphic DNA (RAPD) and sequence characterized
amplified region (SCAR) markers associated with NCLB resistance. Bulked segregant analysis (BSA) was used to search for RAPD
markers linked to NCLB resistance genes, using F2 segregating population obtained by crossing a susceptible inbred ‘209W’ line with a resistant inbred ‘241W’ line. Two hundred
and twenty-two decamer primers were screened to identify four RAPD markers: OPA07521, OPA16457, OPB09520, and OPE20536 linked to NCLB resistance phenotype. These markers were converted into dominant SCAR markers: SCA07496, SCA16420, SCB09464, and SCE20429, respectively. The RAPD and SCAR markers were developed successfully to identify NCLB resistant genotypes in segregating
progenies carrying NCLB resistant traits. Thus, the markers identified in this study should be applicable for MAS for the
NCLB resistance in waxy corn breeding programs. 相似文献
20.
Haploid selection for traits related to pollen cold tolerance in tomato was performed in segregating populations derived from a Lycopersicon esculentum × L. pennellii hybrid. BC1 populations were obtained by combining normal and low temperature treatments on two stages of pollen development: pollen formation, and germination and pollen tube growth. F1 hybrids were cultivated under low and normal temperatures and their pollen was used to pollinate L. esculentum plants at low and normal temperatures. The four BC1 populations obtained were tested for the quality and quantity of pollen produced at low temperatures. The population obtained by cold treatment at both stages had a significantly improved pollen germination ability at low temperatures. The two other coldselected BC1 populations showed no differences compared with the unselected BC population. A second cycle of pollen selection, corresponding to BC2, was applied in order to test its persistence in the subsequent generations and the possibility to further improve the character. This second cycle showed no improvement although some plants retained the high pollen germination ability at low temperatures that was observed in the first cycle. Hence, gametophytic selection of some characters related with tomato pollen performance may be feasible, at least for the first cycle of selection. 相似文献