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1.
Developing a deep root system is an important strategy for avoiding drought stress in rice. Using the 'basket' method, the ratio of deep rooting (RDR; the proportion of total roots that elongated through the basket bottom) was calculated to evaluate deep rooting. A new major quantitative trait locus (QTL) controlling RDR was detected on chromosome 9 by using 117 recombinant inbred lines (RILs) derived from a cross between the lowland cultivar IR64, with shallow rooting, and the upland cultivar Kinandang Patong (KP), with deep rooting. This QTL explained 66.6% of the total phenotypic variance in RDR in the RILs. A BC(2)F(3) line homozygous for the KP allele of the QTL had an RDR of 40.4%, compared with 2.6% for the homozygous IR64 allele. Fine mapping of this QTL was undertaken using eight BC(2)F(3) recombinant lines. The RDR QTL Dro1 (Deeper rooting 1) was mapped between the markers RM24393 and RM7424, which delimit a 608.4 kb interval in the reference cultivar Nipponbare. To clarify the influence of Dro1 in an upland field, the root distribution in different soil layers was quantified by means of core sampling. A line homozygous for the KP allele of Dro1 (Dro1-KP) and IR64 did not differ in root dry weight in the shallow soil layers (0-25 cm), but root dry weight of Dro1-KP in deep soil layers (25-50 cm) was significantly greater than that of IR64, suggesting that Dro1 plays a crucial role in increased deep rooting under upland field conditions. 相似文献
2.
J. P. Suh J. U. Jeung J. I. Lee Y. H. Choi J. D. Yea P. S. Virk D. J. Mackill K. K. Jena 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(5):985-995
Low temperature or cold stress is one of the major constraints of rice production and productivity in temperate rice-growing
countries and high-altitude areas in the tropics. Even though low temperature affects the rice plant in all stages of growth,
the percent seed set is damaged severely by cold and this reduces the yield potential of cultivars significantly. In this
study, a new source of cold-tolerant line, IR66160-121-4-4-2, was used as a donor parent with a cold-sensitive cultivar, Geumobyeo,
to produce 153 F8 recombinant inbred lines (RILs) for quantitative trait locus (QTL) analysis. QTL analysis with 175 polymorphic simple sequence
repeat (SSR) markers and composite interval mapping identified three main-effect QTLs (qPSST-3, qPSST-7, and qPSST-9) on chromosomes 3, 7, and 9. The SSR markers RM569, RM1377, and RM24545 were linked to the identified QTLs for cold tolerance
with respect to percent seed set using cold-water (18–19°C) irrigation in the field and controlled air temperature (17°C)
in the greenhouse. The total phenotypic variation for cold tolerance contributed by the three QTLs was 27.4%. RILs with high
percent seed set under cold stress were validated with linked DNA markers and by haplotype analysis that revealed the contribution
of progenitor genomes from the tropical japonica cultivar Jimbrug (Javanica) and temperate japonica cultivar Shen-Nung89-366.
Three QTLs contributed by the cold-tolerant parent were identified which showed additive effect on percent seed set under
cold treatment. This study demonstrated the utility of a new phenotyping method as well as the identification of SSR markers
associated with QTLs for selection of cold-tolerant genotypes to improve temperate rice production. 相似文献
3.
Ramaiah Venuprasad C. O. Dalid M. Del Valle D. Zhao M. Espiritu M. T. Sta Cruz M. Amante A. Kumar G. N. Atlin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,120(1):177-190
An F4:5 population of 490 recombinant inbred lines (RILs) from the cross Apo/2*Swarna was used to detect quantitative trait loci (QTL) with large effects on grain yield under drought stress using bulk-segregant
analysis (BSA). Swarna is an important rainfed lowland rice variety grown on millions of hectares in Asia, but is highly susceptible
to drought and aerobic soil conditions. Apo is an aerobic-adapted variety with moderate tolerance to drought. Two rice microsatellite
(RM) markers, RM324, and RM416, located on chromosomes 2 and 3, respectively, were shown via BSA to be strongly associated
with yield under lowland drought stress. The effects of these QTL were tested in a total of eight hydrological environments
over a period of 3 years. The QTL linked to RM416 (DTY
3.1
) had a large effect on grain yield under severe lowland drought stress, explaining about 31% of genetic variance for the
trait (P < 0.0001). It also explained considerable variance for yield under mild stress in lowland conditions and aerobic environments.
To our knowledge this is the first reported QTL that has a large effect on yield in both lowland drought and aerobic environments.
The QTL linked to RM324 (DTY
2.1
) had a highly significant effect on grain yield in lowland drought stress (R
2 = 13–16%) and in two aerobic trials. The effect of these QTL on grain yield was verified to be not mainly due to phenology
differences. Effects of DTY
3.1
on yield under stress have been observed in several other rice mapping populations studied at IRRI. Results of this study
indicate that BSA is an effective method of identifying QTL alleles with large effects on rice yield under severe drought
stress. The Apo alleles for these large-effect QTL for grain yield under drought and aerobic conditions may be immediately
exploited in marker-assisted-breeding to improve the drought tolerance of Swarna. 相似文献
4.
Yusaku Uga Kazutoshi Okuno Masahiro Yano 《Molecular breeding : new strategies in plant improvement》2010,26(3):533-538
The stele (root vascular cylinder) in plants plays an important role in the transport of water and nutrients from the root
to the shoot. A quantitative trait locus (QTL) on rice chromosome 9 that controls stele transversal area (STA) was previously
detected in an F3 mapping population derived from a cross between the lowland cultivar ‘IR64’, with a small STA, and the upland cultivar ‘Kinandang
Patong’, with a large STA. To identify the gene(s) underlying this QTL, we undertook fine mapping of the locus. We screened
eight plants from BC2F3 lines in which recombination occurred near the QTL. Progeny testing of BC2F4 plants was used to determine the genotype classes for the QTL in each BC2F3 line. Accordingly, the STA QTL Sta1 (Stele Transversal Area 1) was mapped between the InDel markers ID07_12 and ID07_14. A candidate genomic region for Sta1 was defined more precisely between markers RM566 and RM24334, which delimit a 359-kb interval in the reference cultivar ‘Nipponbare’.
A line homozygous for the ‘Kinandang Patong’ allele of Sta1 had an STA approximately 28.4% larger than that of ‘IR64’. However, Sta1 did not influence maximum or total root length, suggesting that this QTL specifically controls STA. 相似文献
5.
Yong Shu Liang Xiao Deng ZhanHui Mming Wang Zhi Qiang GaoZe chuan Lin Dai Bo ChenXi Hong Shen Li Yong Cao Shi Hua Cheng 《Gene》2013
This study aimed to elucidate the genetics of the adult root system in elite Chinese hybrid rice. Several adult root traits in a recombinant inbred line (RIL) population of Xieyou 9308 and two backcross F1 (BCF1) populations derived from the RILs were phenotyped under hydroponic culture at heading stage for quantitative trait locus (QTL) mapping and other statistical analysis. There a total of eight QTLs detected for the root traits. Among of them, a pleiotropic QTL was repeatedly flanked by RM180 and RM5436 on the short arm of chromosome 7 for multiple traits across RILs and its BCF1 populations, accounting for 6.88% to 25.26% of the phenotypic variances. Only additive/dominant QTLs were detected for the root traits. These results can serve as a foundation for facilitating future cloning and molecular breeding. 相似文献
6.
Fine Mapping QTL for Drought Resistance Traits in Rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) Using Bulk Segregant Analysis 总被引:1,自引:0,他引:1
Salunkhe AS Poornima R Prince KS Kanagaraj P Sheeba JA Amudha K Suji KK Senthil A Babu RC 《Molecular biotechnology》2011,49(1):90-95
Drought stress is a major limitation to rice (Oryza sativa L.) yields and its stability, especially in rainfed conditions. Developing rice cultivars with inherent capacity to withstand
drought stress would improve rainfed rice production. Mapping quantitative trait loci (QTLs) linked to drought resistance
traits will help to develop rice cultivars suitable for water-limited environments through molecular marker-assisted selection
(MAS) strategy. However, QTL mapping is usually carried out by genotyping large number of progenies, which is labour-intensive,
time-consuming and cost-ineffective. Bulk segregant analysis (BSA) serves as an affordable strategy for mapping large effect
QTLs by genotyping only the extreme phenotypes instead of the entire mapping population. We have previously mapped a QTL linked
to leaf rolling and leaf drying in recombinant inbred (RI) lines derived from two locally adapted indica rice ecotypes viz., IR20/Nootripathu using BSA. Fine mapping the QTL will facilitate its application in MAS. BSA was done
by bulking DNA of 10 drought-resistant and 12 drought-sensitive RI lines. Out of 343 rice microsatellites markers genotyped,
RM8085 co-segregated among the RI lines constituting the respective bulks. RM8085 was mapped in the middle of the QTL region
on chromosome 1 previously identified in these RI lines thus reducing the QTL interval from 7.9 to 3.8 cM. Further, the study
showed that the region, RM212–RM302–RM8085–RM3825 on chromosome 1, harbours large effect QTLs for drought-resistance traits
across several genetic backgrounds in rice. Thus, the QTL may be useful for drought resistance improvement in rice through
MAS and map-based cloning. 相似文献
7.
Kenta Shirasawa Takuma Sekii Yoshinori Ogihara Teppei Yamada Sachiko Shirasawa Sachie Kishitani Kunihiko Sasaki Minoru Nishimura Kuniaki Nagano Takeshi Nishio 《Molecular breeding : new strategies in plant improvement》2013,32(1):223-232
An unusually high temperature during the grain-filling period, such as that caused by global warming, impairs the quality of rice (Oryza sativa L.) grains. This sensitivity to high-temperature stress is different among cultivars, suggesting the possibility of developing a high-temperature-tolerant cultivar. Since marker-assisted selection would reduce time and labor in breeding for such a quantitative trait, we determined the chromosomal region responsible for high-temperature tolerance during the grain-filling period. A high-temperature-sensitive japonica cultivar Tohoku 168 and a tolerant japonica cultivar Kokoromachi were selected as the parental lines of recombinant inbred lines (RILs) by high-temperature stress treatment from 5 to 10 days after anthesis, which was found to be the period most critical for grain quality. Using the RILs, whose genotypes were determined by analysis with 131 DNA markers which were selected as polymorphic markers between these two cultivars from 2,648 DNA markers tested, the quantitative trait locus (QTL) for the percentage of white-back grains was mapped on chromosome 6. The Kokoromachi allele of the QTL, which had a positive additive effect on the high-temperature tolerance, was introduced into the Tohoku 168 genome by repeated backcrossings with marker-assisted selection. Using high-temperature stress treatment of the near isogenic lines developed, the QTL on chromosome 6 was localized within a 1.9-Mb region between two DNA markers, ktIndel001 and RFT1. These DNA markers would be useful not only for breeding high-temperature-tolerant cultivars but also for map-based cloning of the QTL. 相似文献
8.
Yan CJ Zhou JH Yan S Chen F Yeboah M Tang SZ Liang GH Gu MH 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(8):1093-1100
Panicle erectness (PE) is one of the most important traits for high-yielding japonica cultivars. Although several cultivars
with PE trait have been developed and released for commercial production in China, there is little information on the inheritance
of PE traits in rice. In the present study, 69 widely cultivated japonica cultivars and a double haploid (DH) population derived from a cross between a PE cultivar (Wuyunjing 8) and a drooping panicle
cultivar (Nongken 57) were utilized to elucidate the mechanisms of PE formation and to map PE associated genes. Our data suggested
that panicle length (PL) and plant height (PH) significantly affected panicle curvature (PC), with shorter PL and PH resulting
in smaller PC and consequently more erect. A putative major gene was identified on chromosome 9 by molecular markers and bulk
segregant analysis in DH population. In order to finely map the major gene, all simple sequence repeats (SSR) markers on chromosome
9 as well as 100 newly developed sequence-tagged site (STS) markers were used to construct a linkage group for quantitative
trait locus (QTL) mapping. A major QTL, qPE9-1, between STS marker H90 and SSR marker RM5652, was detected, and accounted for 41.72% of PC variation with pleiotropic effect
on PH and PL. another QTL, qPE9-2, was also found to be adjacent to qPE9-1. In addition, we found that H90, the nearest marker to qPE9-1, used for genotyping 38 cultivars with extremely erect and drooping panicles, segregated in agreement with PC, suggesting
the H90 product was possibly part of the qPE9-1 gene or closely related to it. These data demonstrated that H90 could be used for marker-aided selection for the PE trait
in breeding and in the cloning of qPE9-1. 相似文献
9.
Y. F. Tan M. Sun Y. Z. Xing J. P. Hua X. L. Sun Q. F. Zhang H. Corke 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):1037-1045
Milling properties, protein content, and flour color are important factors in rice. A marker-based genetic analysis of these
traits was carried out in this study using recombinant inbred lines (RILs) derived from an elite hybrid cross ’Shanyou 63’,
the most-widely grown rice hybrid in production in China. Correlation analysis shows that the traits were inter-correlated,
though the coefficients were generally small. Quantitative trait locus (QTL) analysis with both interval mapping (IM) and
composite interval mapping (CIM) revealed that the milling properties were controlled by the same few loci that are responsible
for grain shape. The QTL located in the interval of RM42-C734b was the major locus for brown rice yield, and the QTL located in the interval of C1087-RZ403 was the major locus for head rice yield. These two QTLs are the loci for grain width and length, respectively. The Wx gene plays a major role in determining protein content and flour color, and is modified by several QTLs with minor effect.
The implications of the results in rice breeding were discussed.
Received: 15 September 2000 / Accepted: 31 March 2001 相似文献
10.
粳稻子预44中稻瘟病数量抗性位点分析 总被引:4,自引:2,他引:2
稻瘟病是世界范围内影响水稻(Oryza sativa)生产的主要病害。抗稻瘟病基因的发掘和育种利用是控制稻瘟病经济、环保的有效措施。为了揭示云南地方水稻品种子预44广谱持久抗瘟机制, 利用江南香糯和子预44杂交构建的F7重组自交群体, 采用苗期稻瘟病菌自然诱发接种法, 通过调查田间抗瘟性表型数据, 结合基因型数据对子预44中的数量抗瘟性位点进行了分析。结果表明, 在连锁系数(logarithm of odds, LOD)大于2.0的域值上, 共检测出13个QTLs, 分别位于第1、2、6、8、12号染色体上。不同位点表型贡献值差异较大, 范围为5.8%-21.9%, 其中8号染色体上标记RM72-RM404之间的QTLs可解释约61.9%的表型变异, 很可能为一个主效抗瘟QTL位点。多个位点的主效和微效抗性相结合可能是子预44持久稻瘟病抗性的分子基础。 相似文献
11.
Lei Zhou Yawen Zeng Weiwei Zheng Bo Tang Shuming Yang Hongliang Zhang Jinjie Li Zichao Li 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(5):895-905
Low temperature at the booting stage is a serious abiotic stress in rice, and cold tolerance is a complex trait controlled
by many quantitative trait loci (QTL). A QTL for cold tolerance at the booting stage in cold-tolerant near-isogenic rice line
ZL1929-4 was analyzed. A total of 647 simple sequence repeat (SSR) markers distributed across 12 chromosomes were used to
survey for polymorphisms between ZL1929-4 and the cold-sensitive japonica cultivar Towada, and nine were polymorphic. Single
marker analysis revealed that markers on chromosome 7 were associated with cold tolerance. By interval mapping using an F2 population from ZL1929-4 × Towada, a QTL for cold tolerance was detected on the long arm of chromosome 7. The QTL explained
9 and 21% of the phenotypic variances in the F2 and F3 generations, respectively. Recombinant plants were screened for two flanking markers, RM182 and RM1132, in an F2 population with 2,810 plants. Two-step substitution mapping suggested that the QTL was located in a 92-kb interval between
markers RI02905 and RM21862. This interval was present in BAC clone AP003804. We designated the QTL as qCTB7 (quantitative trait locus for cold tolerance at the booting stage on chromosome 7), and identified 12 putative candidate
genes. 相似文献
12.
Wang L Wang A Huang X Zhao Q Dong G Qian Q Sang T Han B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(2):327-340
Mapping chromosome regions responsible for quantitative phenotypic variation in recombinant populations provides an effective
means to characterize the genetic basis of complex traits. We conducted a quantitative trait loci (QTL) analysis of 150 rice
recombinant inbred lines (RILs) derived from a cross between two cultivars, Oryza sativa ssp. indica cv. 93-11 and Oryza sativa ssp. japonica cv. Nipponbare. The RILs were genotyped through next-generation sequencing, which accurately determined the recombination
breakpoints and provided a new type of genetic markers, recombination bins, for QTL analysis. We detected 49 QTL with phenotypic
effect ranging from 3.2 to 46.0% for 14 agronomics traits. Five QTL of relatively large effect (14.6–46.0%) were located on
small genomic regions, where strong candidate genes were found. The analysis using sequencing-based genotyping thus offers
a powerful solution to map QTL with high resolution. Moreover, the RILs developed in this study serve as an excellent system
for mapping and studying genetic basis of agricultural and biological traits of rice. 相似文献
13.
Four rice QTL controlling number of spikelets per panicle expressed the characteristics of single Mendelian gene in near isogenic backgrounds 总被引:2,自引:0,他引:2
Yushan Zhang Lijun Luo Touming Liu Caiguo Xu Yongzhong Xing 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(6):1035-1044
Development of quantitative trait loci (QTL) near isogenic lines is a crucial step to QTL isolation using the strategy of
map-based cloning. In this study, a recombinant inbred line (RIL) population derived from two indica rice varieties, Zhenshan 97 and HR5, was employed to map QTL for spikelets per panicle (SPP). One major QTL (qSPP7) and three minor QTL (qSPP1, qSPP2 and qSPP3) were identified on chromosomes 7, 1, 2 and 3, respectively. Four sets of near isogenic lines (NILs) BC4F2 targeted for the four QTL were developed by following a standard procedure of consecutive backcross, respectively. These
QTL were not only validated in corresponding NILs, but also explained amounts of phenotypic variation with much larger LOD
scores compared with those identified in RILs. SPP in the four QTL-NILs expressed bimodal or discontinuous distributions and
followed the expected segregation ratio of single Mendelian factor by progeny test. Finally, qSPP1, qSPP2, qSPP3 and qSPP7 were respectively mapped to a locus, 0.5 cM from MRG2746, 0.6 cM from MRG2762, 0.8 cM from RM49 and 0.7 cM from MRG4436,
as co-dominant markers on the basis of progeny tests. These results indicate no matter how small effect minor QTL is, QTL
may still express the characteristics of single Mendelian factor in NILs and isolation of minor QTL will be possible using
high quality NILs. Pyramiding these QTL into a variety will largely enhance rice grain yield. 相似文献
14.
Quantitative trait loci (QTL) detection was carried out for adventitious rooting and associated propagation traits in a second-generation
outbred Corymbia torelliana × Corymbia citriodora subspecies variegata hybrid family (n = 186). The parental species of this cross are divergent in their capacity to develop roots adventitiously on stem cuttings
and their propensity to form lignotubers. For the ten traits studied, there was one or two QTL detected, with some QTL explaining
large amounts of phenotypic variation (e.g. 66% for one QTL for percentage rooting), suggesting that major effects influence
rooting in this cross. Collocation of QTL for many strongly genetically correlated rooting traits to a single region on linkage
group 12 suggested pleiotropy. A three locus model was most parsimonious for linkage group 12, however, as differences in
QTL position and lower genetic correlations suggested separate loci for each of the traits of shoot production and root initiation.
Species differences were thought to be the major source of phenotypic variation for some rooting rate and root quality traits
because of the major QTL effects and up to 59-fold larger homospecific deviations (attributed to species differences) relative
to heterospecific deviations (attributed to standing variation within species) evident at some QTL for these traits. A large
homospecific/heterospecific ratio at major QTL suggested that the gene action evident in one cross may be indicative of gene
action more broadly in hybrids between these species for some traits. 相似文献
15.
Gene actions of QTLs affecting several agronomic traits resolved in a recombinant inbred rice population and two backcross populations 总被引:15,自引:0,他引:15
Mei HW Li ZK Shu QY Guo LB Wang YP Yu XQ Ying CS Luo LJ 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(4):649-659
To understand the types of gene action controlling seven quantitative traits in rice, we carried out quantitative trait locus (QTL) mapping in order to distinguish between the main-effect QTLs (M-QTLs) and digenic epistatic QTLs (E-QTLs) responsible for the trait performance of 254 recombinant inbred lines (RILs) from rice varieties Lemont/Teqing and two backcross hybrid (BCF1) populations derived from these RILs. We identified 44 M-QTL and 95 E-QTL pairs in the RI and BCF1 populations as having significant effects on the mean values and mid-parental heterosis of heading date, plant height, flag leaf length, flag leaf width, panicle length, spikelet number and spikelet fertility. The E-QTLs detected collectively explained a larger portion of the total phenotypic variation than the M-QTLs in both the RI and BCF1 populations. In both BCF1 populations, over-dominant (or under-dominant) loci were more important than additive and complete or partially dominant loci for M-QTLs and E-QTL pairs, thereby supporting prior findings that overdominance resulting from epistatic loci are the primary genetic basis of inbreeding depression and heterosis in rice. 相似文献
16.
Gloria Burow John J. Burke Zhanguo Xin Cleve D. Franks 《Molecular breeding : new strategies in plant improvement》2011,28(3):391-402
Soil temperatures at 15°C or below limit germination and seedling establishment for warm season cereal crops such as sorghum
(Sorghum bicolor (L.) Moench) during early-season planting. To better understand the genetics of early-season cold tolerance in sorghum, mapping
of quantitative trait loci (QTL) associated with germination, emergence and vigor using a recombinant inbred mapping population
was carried out. A mapping population consisting of 171 F7–F8 recombinant inbred lines (RILs) derived from the cross between RTx430 (cold-sensitive) and PI610727 (cold-tolerant) was developed
and a genetic map was constructed using 141 microsatellites or simple sequence repeat (SSR) markers. The RILs were evaluated
for cold and optimal temperature germinability in the laboratory, field emergence, and seedling vigor in two locations during
early-season planting. Two or more QTL were detected for all traits, except for seedling vigor, with only one QTL was detected
in the population. A QTL for cold germinability (Germ 12-2.1) showed the highest LOD value and was also associated with optimal germinability. One of the QTL for field emergence, Fearlygerm-9.3, a contribution from PI610727, was found significant in both locations used for the study. This study showed alignment of
QTL in SBi1 (Fearlygerm-1.2 and FGerm30-1.2) with previously reported QTL associated with late field emergence identified from a different mapping population. This indicates
that PI617027 shares some common loci with other known early-season cold-tolerant sorghum germplasm but also harbors novel
QTL that could be useful in introgression of enhanced laboratory germination and early-season field emergence. 相似文献
17.
Jun TH Rouf Mian MA Michel AP 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(1):13-22
The soybean aphid (Aphis glycines Matsumura) is the most damaging insect pest of soybean [Glycine max (L.) Merr.] in North America. New soybean aphid biotypes have been evolving quickly and at least three confirmed biotypes
have been reported in USA. These biotypes are capable of defeating most known aphid resistant soybean genes indicating the
need for identification of new genes. Plant Introduction (PI) 567301B was earlier identified to have antixenosis resistance
against biotype 1 and 2 of the soybean aphid. Two hundred and three F7:9 recombinant inbred lines (RILs) developed from a cross of soybean aphid susceptible cultivar Wyandot and resistant PI 567301B
were used for mapping aphid resistance genes using the quantitative trait loci (QTL) mapping approach. A subset of 94 RILs
and 516 polymorphic SNP makers were used to construct a genome-wide molecular linkage map. Two candidate QTL regions for aphid
resistance were identified on this linkage map. Fine mapping of the QTL regions was conducted with SSR markers using all 203
RILs. A major gene on chromosome 13 was mapped near the previously identified Rag2 gene. However, an earlier study revealed that the detached leaves of PI 567301B had no resistance against the soybean aphids
while the detached leaves of PI 243540 (source of Rag2) maintained aphid resistance. These results and the earlier finding that PI 243540 showed antibiosis resistance and PI 567301B
showed antixenosis type resistance, indicating that the aphid resistances in the two PIs are not controlled by the same gene.
Thus, we have mapped a new gene near the Rag2 locus for soybean aphid resistance that should be useful in breeding for new aphid-resistant soybean cultivars. Molecular
markers closely linked to this gene are available for marker-assisted breeding. Also, the minor locus found on chromosome
8 represents the first reported soybean aphid-resistant locus on this chromosome. 相似文献
18.
Showkat Ahmad Ganie Mrinmoi Jyoti Borgohain Kashyap Kritika Akshay Talukdar Dipti Ranjan Pani Tapan Kumar Mondal 《Physiology and Molecular Biology of Plants》2016,22(1):107-114
Eight Saltol quantitative trait locus (QTL) linked simple sequence repeat (SSR) markers of rice (Oryza sativa L.) were used to study the polymorphism of this QTL in 142 diverse rice genotypes that comprised salt tolerant as well as sensitive genotypes. The SSR profiles of the eight markers generated 99 alleles including 20rare alleles and 16 null alleles. RM8094 showed the highest number (13) of alleles followed by RM3412 (12), RM562 (11), RM493 (9) and RM1287 (8) while as, RM10764 and RM10745 showed the lowest number (6) of alleles. Based on the highest number of alleles and PIC value (0.991), we identified RM8094 as suitable marker for discerning salt tolerant genotypes from the sensitive ones. Based upon the haplotype analysis using FL478 as a reference (salt tolerant genotypes containing Saltol QTL), we short listed 68 rice genotypes that may have at least one allele of FL478 haplotype. Further study may confirm that some of these genotypes might have Saltol QTL and can be used as alternative donors in salt tolerant rice breeding programmes. 相似文献
19.
Selvaraj Michael Gomez N. Manikanda Boopathi S. Satheesh Kumar T. Ramasubramanian Zhu Chengsong P. Jeyaprakash A. Senthil R. Chandra Babu 《Acta Physiologiae Plantarum》2010,32(2):355-364
Drought is a major limitation for rice production in rainfed ecosystems. Identifying quantitative trait loci (QTLs) linked
to drought resistance provides opportunity to breed high yielding rice varieties suitable for drought-prone areas. Although
considerable efforts were made in mapping QTLs associated with drought-resistance traits in rice, most of the studies involved
indica × japonica crosses and hence, the drought-resistance alleles were contributed mostly by japonica ecotypes. It is desirable to look for genetic variation within indica ecotypes adapted to target environment (TE) as the alleles from japonica ecotype may not be expressed under lowland conditions. A subset of 250 recombinant inbred lines (RILs) of F8 generation derived from two indica rice lines (IR20 and Nootripathu) with contrasting drought-resistance traits were used to map the QTLs for morpho-physiological
and plant production traits under drought stress in the field in TE. A genetic linkage map was constructed using 101 polymorphic
PCR-based markers distributed over the 12 chromosomes covering a total length of 1,529 cM in 17 linkage groups with an average
distance of 15.1 cM. Composite interval mapping analysis identified 22 QTLs, which individually explained 4.8–32.2% of the
phenotypic variation. Consistent QTLs for drought-resistance traits were detected using locally adapted indica ecotypes, which may be useful for rainfed rice improvement. 相似文献
20.
Zennia Jean C. Gonzaga Jerome Carandang Anshuman Singh Bertrand C.Y. Collard Michael J. Thomson Endang M. Septiningsih 《Molecular breeding : new strategies in plant improvement》2017,37(4):47
Submergence is a widespread problem of rice production, especially in low-lying areas in South and Southeast Asia. Despite the success of Sub1 mega varieties, repeated instances of prolonged and severe flooding in stress-prone areas suggests that the SUB1 gene is no longer sufficient in those regions and requires improved varieties with increased tolerance. A study was conducted to identify quantitative trait loci (QTLs) associated with submergence tolerance using 115 F7 recombinant inbred lines (RILs) derived from the cross of Ciherang-Sub1, a popular Indonesian cultivar carrying the SUB1 gene that has relatively higher tolerance to submergence compared to the performance of most other Sub1 lines and the submergence and stagnant flooding tolerant IR10F365. As the tolerant allele at SUB1A on chromosome 9 was fixed in this mapping population, additional QTLs responsible for submergence tolerance were expected to be revealed. Genotyping with an Infinium 6K SNP chip resulted in 469 polymorphic markers that were then used for QTL mapping. Phenotyping was performed under complete submergence with two replicates. A major QTL for submergence derived from Ciherang-Sub1, named qSUB8.1, was detected on chromosome 8 with a LOD score of 10.3 and phenotypic variance of 27.5%. Additionally, a smaller QTL, also derived from Ciherang-Sub1, was detected on chromosome 2 with a LOD score of 3.5 and phenotypic variance of 12.7%. There was no digenic interaction detected between these QTLs suggesting their independent action. The QTLs detected in this study can be used in marker-assisted selection to further improve the tolerance of other Sub1 varieties. 相似文献