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1.
Molecular mapping of the reverse thermo-sensitive genic male-sterile gene (rtms1) in rice 总被引:9,自引:0,他引:9
J. H. Jia D. S. Zhang C. Y. Li X. P. Qu S. W. Wang V. Chamarerk H. T. Nguyen B. Wang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(4):607-612
TGMS (thermo-sensitive genic male-sterile) rice is widely used in hybrid rice production. Because of a specific temperature
requirement, it can be used only in a narrow rice-growing zone in Asia. A newly discovered reverse thermo-sensitive genic
male-sterile line, J207S, has an opposite phynotype compared to the normal TGMS lines. J207S is completely sterile when the
temperature is lower than 31°C. Thus, it can be widely used in a larger area. Genetic analysis indicated that the sterility
of J207S was controlled by a single recessive gene which was first named as rtms1. An F2 population from the cross between J207S and E921 was developed and used for molecular mapping of the rtms1 gene. The AFLP (amplified fragment length polymorphism) technique, combined with BSA (bulked segregant analysis), was used
to screen markers linked to the target gene, and eight polymorphic AFLP loci were identified. Co-segregating analysis using
the F2 population showed that two of them, Rev1 and Rev7, were closely linked to the target gene with a recombinant rate of 3.8%
and 7.7%, respectively. Both Rev1 and Rev7 were found to be single-copy sequences through Southern analysis. Rev1 was subsequently
mapped on chromosome 10 with a doubled-haploid mapping populations derived from the cross CT9993 × IR62266 available at Texas
Tech University. RM222 and RG257 were linked to Rev1 at a distance of 11.8 cM and 4.6 cM, respectively. Additional SSR markers
from the rice map of Cornell University, RFLP markers from the map of RGP in Japan and the map of Texas Tech University were
selected from the region surrounding Rev1 on chromosome 10 to conduct the fine-mapping of the rtms1 gene. Presently, rtms1 was mapped between RM239 and RG257 with genetic distance of 3.6 cM and 4.0 cM, respectively. The most-closely linked AFLP
marker, Rev1, 4.2 cM from the rtms1 gene, was sequenced and converted into a SCAR (sequence characterized amplified region) marker which could facilitate marker-assisted
selection of the rtms1 gene.
Received: 2 November 2000 / Accepted: 21 November 2000 相似文献
2.
Genetic analysis,molecular tagging and mapping of the thermo-sensitive genic male-sterile gene (wtms1) in wheat 总被引:4,自引:0,他引:4
Xing QH Ru ZG Zhou CJ Xue X Liang CY Yang DE Jin DM Wang B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(8):1500-1504
A thermo-sensitive genic male-sterile (TGMS) wheat line ( Triticum aestivum L.) BNY-S was obtained from the spontaneous mutant of BNY-F. Its fertility was decided by the temperature during the differentiation stage of the spikelets. BNY-S was completely sterile when the temperature was lower than 10 degrees C during the differentiation stage of the spikelets, but fertile when the temperature was higher than 10 degrees C. Genetic analysis indicated that the sterility of BNY-S was controlled by a single recessive gene, which was named as wtms1. An F(2) population, consisting of 3,000 individuals from the cross between BNY-S and Lankao 52-24, was used for genetic analysis and statistical analysis of the TGMS and, out of them, 158 sterile and 93 fertile extremes were present for molecular tagging and mapping of the wtms1 gene. SSR (simple sequence repeat) and AFLP (amplified fragment length polymorphism) techniques combined with BSA (bulked segregant analysis) were used to screen markers linked to the target gene. As a result, wtms1 was preliminarily mapped on chromosome 2B according to SSR analysis. In AFLP analysis, 14 polymorphic AFLP loci were identified with a linkage relation to the wtms1 gene. Then linkage analysis using the F(2) population showed that three of them, E: AAG/M: CTA(163), E: AGG/M: CTC(220) and E: ACA/M: CTA(160), were linked to the wtms1 gene relatively close to a genetic distance of 6.9 cM, 6.9 cM and 13.9 cM, respectively. Finally, the wtms1 gene was mapped between the SSR marker Xgwm 374 and the AFLP marker E: AAG/M: CTA(163) with the distance of 4.8 cM and 6.9 cM, respectively. A partial linkage map was constructed according the SSR and AFLP data. 相似文献
3.
Genetic characterization and fine mapping of a novel thermo-sensitive genic male-sterile gene tms6 in rice (Oryza sativa L.) 总被引:5,自引:0,他引:5
Lee DS Chen LJ Suh HS 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(7):1271-1277
The application of genetic male sterility in hybrid rice production has great potential to revolutionize hybrid seed production
methodology. The two-line breeding system by using thermo-sensitive genic male sterility (TGMS) has been discovered and successfully
developed as a breeding strategy in rice. One TGMS gene was investigated by a spontaneous rice mutant line, Sokcho-MS, originated
from a Korean japonica variety. It was shown that Sokcho-MS is completely sterile at a temperature higher than 27°C and/or lower than 25°C during
the development of spikelets, but fertile at the temperature ranging from 25 to 27°C regardless of the levels of day-length.
Genetic analysis and molecular mapping based on SSR, STS and EST markers revealed that a single recessive gene locus involved
the control of genic male sterility in Sokcho-MS. By using an F2 mapping population derived from a cross between Sokcho-MS and a fertile indica variety Neda, the new TGMS gene, designated as tms6, was mapped primarily to the long arm of chromosome 5 of Oryza sativa at the interval between markers E60663 (2.0 cM) and RM440 (5.8 cM). Subsequently, tms6 was fine mapped to the interval between markers RM3351 (0.1 cM) and E60663 (1.9 cM). As tms6 appeared to be independent of other mapped TGMS genes in rice, the genetic basis of Sokcho-MS was further discussed. 相似文献
4.
Fine mapping of the rice thermo-sensitive genic male-sterile gene <Emphasis Type="Italic">tms5</Emphasis> 总被引:10,自引:0,他引:10
Wang YG Xing QH Deng QY Liang FS Yuan LP Weng ML Wang B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(5):917-921
AnnongS-1, a thermo-sensitive genic male-sterile (TGMS) rice line, has a new TGMS gene. Genetic analysis indicated that the sterility of AnnongS-1 was controlled by a single resessive gene named tms5. In our previous studies based on an F2 population from the cross between AnnongS-1 and Nanjing11, tms5 was mapped on chromosome 2. Recently, a RIL (recombinant inbred line) population from the same cross was developed and used for the fine mapping of the tms5 gene. Molecular marker techniques combined with BSA (bulked segregant analysis) were used. As a result, two AFLP markers (AF10, AF8), one RAPD marker (RA4), one STS marker (C365-1), one CAPs marker (G227-1) and four SSR markers (RM279, RM492, RM327, RM324) were found to be closely linked to tms5 gene. The DNA sequences of the RFLP marker of C365 and G227 were found in GenBank, and on the basis of these sequences, many primers were designed to amplify the two parents and their RIL population plants. Finally, the tms5 gene was mapped between STS marker C365-1 and CAPs marker G227-1 at a distance of 1.04 cM from C365-1 and 2.08 cM from G227-1.Communicated by H.F. LinskensY.G. Wang and Q.H. Xing contributed equally to this contribution. 相似文献
5.
Molecular mapping of the ge
s gene controlling the super-giant embryo character in rice (Oryza sativa L.) 总被引:8,自引:0,他引:8
H. -J. Koh M. -H. Heu S. R. McCouch 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(1-2):257-261
The giant-embryo character is useful for quality improvement in rice. Three alleles controlling embryo size have been reported at the ge locus. Based on trisomic analysis, this locus is known to reside on chromosome 7. The objective of the present study was to identify linkage between molecular markers and the ge
s
gene using an existing molecular map of rice and an F2 population derived from Hwacheongbyeo-ge
s
(super-giant embryo)/Milyang 23. The bulked-segregant method was used to screen 38 RFLPs and two microsatellite markers from rice chromosome 7. RZ395 and CDO497 flanked the ge
s
gene, at 2.4 cM and 3.4 cM, respectively. The two microsatellite markers, RM18 and RM10, were linked with ge
s
at 7.7 cM and 9.6 cM, respectively. The availability of molecular markers will facilitate selection of this grain character in a breeding program and provide the foundation for map-based gene isolation. 相似文献
6.
S. Garland L. Lewin A. Blakeney R. Reinke R. Henry 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(3):364-371
The genomic DNA clone RG28, linked to the major fragrance gene of rice (fgr), was assessed for polymorphism in order to produce a PCR-based marker for fragrance. A small mono-nucleotide repeat, that
was polymorphic between a pair of fragrant and non-fragrant cultivars, was identified and developed into a co-dominant PCR-based
marker. The polymorphism-information-content determinations for three microsatellite markers, that have been genetically mapped
near RG28, are also presented. These PCR-based markers will be highly useful in distinguishing fragrance-producing alleles
from non-fragrance-producing alleles at the fgr locus.
Received: 19 October 1999 / Accepted: 16 December 1999 相似文献
7.
S. Fukuoka H. Namai K. Okuno 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):446-449
Complementary recessive genes hwd1 and hwd2 controlling hybrid breakdown (weakness of F2 and later generations) were mapped in rice using RFLP markers. These genes produce a plant that is shorter and has fewer
tillers than normal plants when the two loci have only one or no dominant allele at both loci. A cultivar with two dominant
alleles at the hwd1 locus and a cultivar with two dominant alleles at the hwd2 locus were crossed with a double recessive tester line. Linkage analysis was carried out for each gene independently in two
F2 populations derived from these crosses. hwd1 was mapped on the distal region of rice genetic linkage map for chromosome 10, flanked by RFLP markers C701 and R2309 at
a distance of 0.9 centiMorgans (cM) and 0.6 cM, respectively. hwd2 was mapped in the central region of rice genetic linkage map for chromosome 7, tightly linked with 4 RFLP markers without
detectable recombination. The usefulness of RFLP mapping and map information for the genes controlling reproductive barriers
are discussed in the context of breeding using diverse rice germplasm, especially gene introduction by marker-aided selection. 相似文献
8.
V. H. Beaumont J. Mantet T. R. Rocheford J. M. Widholm 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(4):606-612
The F2 generations from two maize crosses were used to compare the ability of RAPD and RFLP marker systems to create a genetic linkage map. Both RFLPs and RAPDs were shown to provide Mendelian-type markers. Most of the RFLPs (80%) could be placed with a good level of certainty (LOD>4) on the genetic linkage map. However, because of their dominant nature, only between 37% and 59% of the RAPDs could be placed with such a LOD score. The use of combined data from RFLPs and RAPDs increases the level of information provided by RAPDs and allows the creation of a combined RFLP/RAPD genetic linkage map. Thus, the RAPD technique was found to be a powerful method to provide improved probes coverage on a previously created RFLP map and to locate markers linked to chromosomal regions of interest. 相似文献
9.
Molecular mapping of a rice gene conditioning thermosensitive genic male sterility using AFLP, RFLP and SSR techniques 总被引:19,自引:0,他引:19
N. V. Dong P. K. Subudhi P. N. Luong V. D. Quang T. D. Quy H. G. Zheng B. Wang H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(5):727-734
The discovery and application of the thermosensitive genic male sterility (TGMS) system has great potential for revolutionizing
hybrid seed production technology in rice. Use of the TGMS system in two-line breeding is simple, inexpensive, efficient,
and eliminates the limitations associated with the cytoplasmic-genetic male sterility (CMS) system. An F2 population developed from a cross between a TGMS indica mutant, TGMS–VN1, and a fertile indica line, CH1, was used to identify molecular markers linked to the TGMS gene and to subsequently determine its chromosomal location
on the linkage map of rice. Bulk segregant analysis was performed using the AFLP technique. From the survey of 200 AFLP primer
combinations, four AFLP markers (E2/M5–600, E3/M16–400, E5/M12–600, and E5/M12–200) linked to the TGMS gene were identified.
All the markers were linked to the gene in the coupling phase. All except E2/M5–200 were found to be low-copy sequences. However,
the marker E5/M12–600 showed polymorphism in RFLP analysis and was closely linked to the TGMS gene at a distance of 3.3 cM.
This marker was subsequently mapped on chromosome 2 using doubled-haploid mapping populations derived from the crosses IR64×Azucena
and CT9993×IR62666, available at IRRI, Philippines, and Texas Tech University, respectively. Linkage of microsatellite marker
RM27 with the TGMS gene further confirmed its location on chromosome 2. The closest marker, E5/M12–600, was sequenced so that
a PCR marker can be developed for the marker-assisted transfer of this gene to different genetic backgrounds. The new TGMS
gene is tentatively designated as tms4(t).
Received: 13 July 1999 / Accepted: 27 July 1999 相似文献
10.
L. -X. Yu H. T. Nguyen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,87(6):668-672
Genetic variation of nine upland and four lowland rice cultivars (Oryza sativa L.) was investigated at the DNA level using the randomly amplified polymorphic DNA (RAPD) method via the polymerase chain reaction (PCR). Forty-two random primers were used to amplify DNA segments and 260 PCR products were obtained. The results of agarosegel electrophoretic analysis of these PCR products indicated that 208 (80%) were polymorphic. All 42 primers used in this experiment were amplified and typically generated one-to-four major bands. Only two primers showed no polymorphisms. In general, a higher level of polymorphism was found between japonica and indica subspecies while fewer polymorphisms were found between upland and lowland cultivars within the indica subspecies. A dendrogram that shows the genetic distances of 13 rice cultivars was constructed based on their DNA polymorphisms. Classification of rice cultivars based on the results from the RAPD analysis was identical to the previous classification based on isozyme analysis. This study demonstrated that RAPD analysis is a useful tool in determining the genetic relationships among rice cultivars. 相似文献
11.
Y. G. Cho M. Y. Eun S. R. McCouch Y. A. Chae 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(1):54-59
To establish the location of the semidwarf gene, sd-1, the anthocyanin activator (A), purple node (Pn), purple auricle (Pau), and the isozyme locus, EstI-2, in relation to DNA markers on the molecular linkage map of rice, 20 RFLP markers, previously mapped to the central region of chromosome 1 (McCouch et al. 1988), were mapped onto an F2 population derived from the cross Taichung 65 (A,Pn,Pau)/Taichung 65 (sd-1). sd-1 and EstI-2 were determined to be linked most tightly to RFLP markers RG 109 and RG 220, which cosegregated with each other. The distance between these RFLP markers and sd-1 was estimated to be 0.8 cM, based on an observed recombination value of 0.8%. The order of genes and markers in this region of chromosome 1 was determined to be sd-1 — (EstI-2 — RG220 — RG109) — RG381 — A — Pn — Pau. To test the efficacy of selection for sd-1 based on these linked markers, 50-day-old F2 seedlings derived from another cross, Milyang 23/Gihobyeo, were analyzed for marker genotype. At this age, the semidwarf character could not be clearly detected based on phenotype. In addition, plant height was normally distributed in this population, making it difficult to unambiguously identify plants carrying sd-1. Thirteen seedlings homozygous for the sd-1-associated allele at EstI-2, RG220 and RG109, and 13 seedlings homozygous for the Sd-1-associated allele at all three marker loci were selected for further genetic analysis. At 20 days after heading, the culm lengths of these 26 plants were measured and the expected phenotype was confirmed in every case. These 26 plants were then selfed for four generations and F6 lines were again evaluated to determine whether any recombination among the three molecular markers, or between these markers and the sd-1 gene, could be detected. No recombinants were identified, confirming the tight linkage of these loci and the usefulness of genotypic selection for this recessive semidwarf character prior to the time when it can be evaluated based on phenotype. 相似文献
12.
V. T. Nguyen M. D. Burow H. T. Nguyen B. T. Le T. D. Le A. H. Paterson 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(6-7):1002-1010
Crop productivity on acid soil is restricted by multiple abiotic stress factors. Aluminum (Al) tolerance seems to be a key
to productivity on soil with a pH below 5.0, but other factors such as Mn toxicity and the deficiency of P, Ca and Mg also
play a role. The development of Al-tolerant genotypes of rice is an urgent necessity for improving crop productivity in developing
countries. Inhibition of root growth is a primary and early symptom of Al toxicity. The present study was conducted to identify
genetic factors controlling the aluminum tolerance of rice. Several parameters related to Al tolerance, most importantly the
relative root growth under Al stress versus non-stress conditions, were scored in 188 F3 selfed families from a cross between an Al-tolerant Vietnamese local variety, Chiembau, and an Al-susceptible improved variety,
Omon269–65. The two varieties are both Oryza sativa ssp. indica, but showed a relatively high level of DNA polymorphism, permitting the assembly of an RFLP map consisting of
164 loci spanning 1,715.8 cM, and covering most of the rice genome. A total of nine different genomic regions on eight chromosomes
have been implicated in the genetic control of root and shoot growth under aluminum stress. By far the greatest effects on
aluminum tolerance were associated with the region near WG110 on chromosome 1. This region does not seem to correspond to
most of the genes that have been mapped for aluminum tolerance in other species, nor do they correspond closely to one another.
Most results, both from physiological studies and from molecular mapping studies, tend to suggest that aluminum tolerance
is a complex multi-genic trait. The identification of DNA markers (such as WG110) that are diagnostic for aluminum tolerance
in particular gene pools provides an important starting point for transferring and pyramiding genes that may contribute to
the sustainable improvement of crop productivity in aluminum-rich soils. The isolation of genes responsible for aluminum tolerance
is likely to be necessary to gain a comprehensive understanding of this complex trait.
Received: 29 March 2000 / Accepted: 16 August 2000 相似文献
13.
水稻微卫星标记的发展和应用 总被引:4,自引:0,他引:4
微卫星又称简单序列重复。它是由几个核苷酸(一般2~4个)为重复单位组成的串联重复序列。相同座位上的重复序列由于重复次数的不同而造成序列长度的多态性。微卫星标记是一种共显性标记,具有等位基因丰富、检测技术简单等优点。微卫星标记在基因组作图、品种鉴定、种质保存、分子标记辅助选择等方面有着广泛的应用。目前水稻中已发展了300多个微卫星标记。 相似文献
14.
J. J. Ni P. Wu D. Senadhira N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(8):1361-1369
The amplified fragment length polymorphism (AFLP) technique combined with selective genotyping was used to map quantitative
trait loci (QTLs) associated with tolerance for phosphorus (P) deficiency in rice. P deficiency tolerant cultivar IR20 was
crossed to IR55178-3B-9-3 (sensitive to P-deficiency) and 285 recombinant inbred lines (RILs) were produced by single-seed
descent. The RILs were phenotyped for the trait by growing them in P-sufficient (10.0 mg/l) and P-deficient (0.5 mg/l) nutrient
solution and determining their relative tillering ability at 28 days after seeding, and relative shoot dry weight and relative
root dry weight at 42 days after seeding. Forty two of each of the extreme RILs (sensitive and tolerant) and the parents were
subjected to AFLP analysis. A map consisting of 217 AFLP markers was constructed. Its length was 1371.8 cM with an average
interval size of 7.62 cM. To assign linkage groups to chromosomes, 30 AFLP and 26 RFLP markers distributed over the 12 chromosomes
were employed as anchor markers. Based on the constructed map, a major QTL for P-deficiency tolerance, designated PHO, was
located on chromosome 12 and confirmed by RFLP markers RG9 and RG241 on the same chromosome. Several minor QTLs were mapped
on chromosomes 1, 6, and 9.
Received: 21 April 1998 / Accepted: 9 June 1998 相似文献
15.
水稻矮化相关基因的研究进展 总被引:12,自引:0,他引:12
矮秆水稻的培育成功是20世纪农业最主要的成就之一.本文综述了水稻矮化相关基因的遗传学、激素对矮化基因突变体的调控以及矮化相关基因的克隆等方面的研究进展,并分析了利用基因工程手段控制农作物生长的巨大潜能. 相似文献
16.
Gejiao Wang Stefano Castiglione Jian Zhang Rongzhao Fu Jiangsheng Ma Wenbin Li Yongru Sun Francesco Sala 《Plant cell reports》1994,14(2-3):112-115
Summary DNA from three families of rice plants selected in Northern China (each comprising the male sterile, the restorer, the hybrid F1 and the maintainer lines) has been extracted and amplified by PCR with different random DNA primers (RAPD analysis). Then, DNA has been analysed by agarose gel electrophoresis and DNA bands scored as present or absent. The generated matrices are reproducible and amenable for identification of each single plant line. Thus, RAPD fingerprinting of the inbred parental lines and of the resulting hybrid is proposed as a convenient tool for the identification, protection and parentage determination of plant hybrids. Furthermore, by offering a molecular tool to verify the degree of dissimilarity between the parental lines, the RAPD analysis may also be used to search for new parental combinations. 相似文献
17.
J. P. Gustafson M. Yano 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(3-4):447-453
Minisatellites, or DNA fingerprinting sequences, have been utilized in animal linkage studies for several years but have not
been used as markers for plant genome mapping. In animal genome mapping they have resulted in limited success because they
are evenly dispersed in some species but are often clustered near telomeric regions, as observed on human chromosomes. The
purpose of the present study was to generate DNA fingerprints utilizing several rice-derived minisatellites containing different
core sequences and numbers of repeat units, followed by assessing their potential for use as genetic markers when mapped to
a rice recombinant inbred line (RIL) population. Sites of segregating minisatellite loci were mapped onto 11 of the 12 rice
RIL linkage maps. The implications for the use of rice minisatellite core sequences as genetic markers on linkage maps in
rice are discussed.
Received: 1 March 1999 / Accepted: 22 June 1999 相似文献
18.
Xiangqiang Zhao Guohua Liang Jingsong Zhou Changjie Yan Xiaoying Cao Minghong Gu 《生物学前沿》2006,1(2):93-98
Genetic analysis established that Aitaiyin3,a dwarf rice variety derived from a semidwarf cultivar Taiyin1,carries two recessive semidwarf genes.By using simple sequence repeat(SSR)markers,we mapped the two semidwarf genes,sd-1 and sd-t2 on chromosomes 1 and 4,respectively.Sd-t2 was thus named because the semidrawf gene sd-t has already been identified from Aitaiyin 2 whose origin could be traced back to Taivin1.The result of the molecular mappingof sd-1 gene revealed it is linked to four SSR markers found on chromosome 1.These markers are:RM297,RM302,RM212,and OSR3 spaced at 4.7 cM,0 cM,0.8cM and 0 cM,respectively.Sd-t2 was found to be located on chromosome 4 using five SSR markers:two markers,SSR332 and RM1305 located proximal to sd-t2 are spaced 11.6 cM,3.8 cM,respectively,while the three distally located primers,RM5633,RM307,and RM401 are separated by distances of 0.4 cM,0.0 cM,and 0.4 cM,respectively. 相似文献
19.
Comparison of the genetic diversity of common wild rice (Oryza rufipogon Griff.) and cultivated rice (O. sativa L.) using RFLP markers 总被引:12,自引:0,他引:12
C. Q. Sun X. K. Wang Z. C. Li A. Yoshimura N. Iwata 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(1):157-162
Forty fourth single-copy RFLP markers were used to evaluate the genetic diversity of 122 accessions of common wild rice (CWR,
Oryza rufipogon Griff.) and 75 entries of cultivated rice (Oryza sativa L. ) from more than ten Asian countries. A comparison of the parameters showing genetic diversity, including the percentage
of polymorphic loci (P), the average number of alleles per locus (A), the number of genotypes (Ng), the average heterozygosity (Ho) and the average genetic multiplicity (Hs) of CWR and indica and japonica subspecies of cultivated rice from different countries and regions, indicated that CWR from China possesses the highest genetic
diversity, followed by CWR from South Asia and Southeast Asia. The genetic diversity of CWR from India is the second highest.
Although the average gene diversity (Hs)of the South Asian CWR is higher than that of the Southeast Asian CWR, its percentage of polymorphic loci (P), number of alleles (Na) and number of genotypes (Ng) are all smaller. It was also found that the genetic diversity of cultivated rice is obviously lower than that of CWR. At
the 44 loci investigated, the number of polymorphic loci of cultivated rice is only 3/4 that of CWR, while the number of alleles,
60%, and the number of genotypes is about 1/2 that of CWR. Of the two subspecies studied, the genetic diversity of indica is higher than that of japonica. The average heterozygosity of the Chinese CWR is the highest among all the entries studied. The average heterozygosity of
CWR is about two-times that of cultivated rice. It is suggested that during the course of evolution from wild rice to cultivated
rice, many alleles were lost through natural and human selection, leading to the lower heterozygosity and genetic diversity
of the cultivated rice.
Received: 19 May 1999 / Accepted: 26 April 2000 相似文献
20.
A research was conducted on the pollen fertility of rice sterile lines D52S and D38S responsive to photoperiod during the sensitive stage under natural and controlled conditions. Bulk segregant analysis (BSA) and recessive class approach were applied to identify DNA markers that co-segregate with gene conferring male-sterility in D52S mutant rice. The results showed that in day-light higher or equal to 14.00 h, D52S and D38S rice pollen were fertile; however, they were sterile when day-length was less than 14.00 h. They were therefore considered to be short photo-periodic sensitive genic male sterile lines(Short PGMS lines). Under short day-light conditions, the pollen fertility segregation of F2 populations from crosses between D52S/Shuhui527 and D52S/Gui99showed 3:1 ratio of fertile to sterile plants suggestingthat male sterility in D52S was controlled by one recessive gene. Two markers RM244 and RM216 located on chromosome number 10 co-segregated completely with the rpms locus. The locus was mapped to the interval between SSR markers RM2571 (6.6 cM) and RM244 (4.6 cM). 相似文献