Gossypium raimondii(2n=2x=26,D_(5)),an untapped wild species,is the putative progenitor of the D-subgenome of G.hirsutum(2n=4x=52,AD_(1)),an extensively cultivated species.Here,we developed a G.hirsutum(recipient)–G....Gossypium raimondii(2n=2x=26,D_(5)),an untapped wild species,is the putative progenitor of the D-subgenome of G.hirsutum(2n=4x=52,AD_(1)),an extensively cultivated species.Here,we developed a G.hirsutum(recipient)–G.raimondii(donor)introgression population to exploit the favorable QTLs/genes and mapped potential quantitative trait loci(QTLs)from wild cotton species.The introgression population consisted of 256 lines with an introgression rate of 52.33%for the G.raimondii genome.The introgression segment length range was 0.03–19.12 Mb,with an average of 1.22 Mb.The coverage of total introgression fragments from G.raimondii was 386.98 Mb.Further genome-wide association analysis(Q+K+MLM)and QTL mapping(RSTEP-LRT)identified 59 common QTLs,including 14 stable QTLs and six common QTL(co-QTL)clusters,and one hotspot of micronaire(MIC).The common QTLs for seed index all showed positive additive effects,while the common QTLs for boll weight all had negative additive effects,indicating that the linkage between seed index and boll weight could be broken.QTLs for lint percentage showed positive effects and could be beneficial for improving cotton yield.Most QTLs for fiber quality had negative additive effects,implying these QTLs were domesticated/improved in G.hirsutum.A few fiber quality QTLs showed positive additive effects,so they could be used to improve cotton fiber quality.The introgression lines developed could be useful for molecular marker-assisted breeding and mapping QTLs precisely for mining desirable genes from the wild species G.raimondii.Such genes can improve cultivated cotton in the future through a designbreeding approach.展开更多
Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to ...Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length （MRL） and root-shoot ratio （RS） were induced by P-deficiency stress. Relative MRL （RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency con- dition） and relative RS （RRS） were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits （RMRL, RRS, RRV, and RRDW） and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL （qRRSS） showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.展开更多
[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. ...[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.展开更多
Introgression lines （ILs） are valuable materials for identifying quantitative trait loci （QTLs）, evaluating genetic interactions, and marker assisted breeding. A set of 430 ILs （BC5F3） containing segments from u...Introgression lines （ILs） are valuable materials for identifying quantitative trait loci （QTLs）, evaluating genetic interactions, and marker assisted breeding. A set of 430 ILs （BC5F3） containing segments from upland tropical japonica cultivar IRAT109 in a lowland temperate japonica cultivar Yuefu background were developed. One hundred and seventy-six polymorphic markers were used to identify introgressed segments. No segment from IRAT109 was found in 160 lines. Introgressed segments of the other 270 lines covered 99.1% of the donor genome. The mean number of introgressed donor segments per individual was 3.3 with an average length of 14.4 cM. QTL analysis was conducted on basal root thickness （BRT） of the 270 ILs grown under irrigated lowland, upland and hydroponic conditions. A total of 22 QTLs affecting BRT were identified, six QTLs （qBRT3.1, qBRT3.2, qBRT6.1, qBRTS.2, qBRT9.1, and qBRT9.2） were consistently expressed under at least two environments （location and water regime）, and qBRT7.2 was a new BRT QTL identified under lowland conditions. IL255 containing qBRT9.1 showed an increase of 10.09% and 7.07% BRT over cultivar Yuefu when grown under upland and lowland conditions, respectively. Using a population of 304 F2：3 lines derived from the cross IL255 Yuefu, qBRT9.1 was validated and mapped to a 1.2 cM interval between RM24271 and RM566. The presence of qBRT9.1 explained 12% of BRT variation. The results provide upland rice ILs and BRT QTLs for analyzing the genetic basis of drought resistance, detecting favorable genes from upland rice, and rice drought resistance breeding.展开更多
Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis o...Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis of heterosis for yield and eight related traits.Four testcross(TC) populations with 228 testcross F1 combinations were developed by crossing57 introgression lines with four types of widely used male sterile lines using a North Carolina II mating design.Analysis of variance indicated that the effects of testcross F1 combinations and their parents were significant or highly significant for most of the traits in both years,and all interaction effects with year were significant for most of the traits.Positive midparent heterosis(HMP) was observed for most traits in the four TC populations in the two years.The relative HMPlevels for most traits varied from highly negative to highly positive.Sixty-two dominant-effect QTL were identified for HMPof the nine traits in the four TC populations in the two years.Of these,22 QTL were also identified for the performance of testcross F1.Most dominant-effect QTL could individually explain more than 10% of the phenotypic variation.Four QTL clusters were observed including the region surrounding the RM9–RM297 region on chromosome 1,the RM110–RM279–RM8–RM5699–RM452 region on chromosome 2,the RM5463 locus on chromosome 6 and the RM1146–RM147 region on chromosome 10.The identified QTL for heterosis provide valuable information for dissecting the genetic basis of heterosis.展开更多
Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvem...Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvement. Characterization of maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> IL generations, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest </span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;">-introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> ILs demonstrated that </span><i><span style="font-family:Verdana;">Z</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">mays</span></i><span style="font-family:Verdana;"> ssp. </span><i><span style="font-family:Verdana;">mexicana </span></i><span style="font-family:Verdana;">can serve as a potential source for the enrichment of maize germplasm.</span>展开更多
The present study aimed at breeding new rice germplasms with similar genome but significantly differed in heat tolerance during the grain filling stage.A total of 791 BC1F8 backcross recombinant lines,derived from the...The present study aimed at breeding new rice germplasms with similar genome but significantly differed in heat tolerance during the grain filling stage.A total of 791 BC1F8 backcross recombinant lines,derived from the cross of Xieqingzao B /N22 //Xieqingzao B,were used as materials.Each rice line was separated evenly into two groups,and the heat tolerance of all rice lines were evaluated at natural high temperature in fields.The rice lines with heat tolerant index higher than 90% or lower than 40% were selected to compare the phenotypic characters and further identify heat tolerance at the early milky stage in a phytotron.Rice lines with similar phenotypic characters but significantly differed in heat tolerance at the milky stage were analyzed by 887 simple sequence repeat markers that were evenly distributed on the 12 rice chromosomes.In the result,12(6 pairs) rice lines with similar phenotypic characters but significantly differed in heat tolerance at the milky stage were obtained.Molecular marker analysis indicated that the genomic polymorphism between 703T and 704S was the smallest in the 6 pairs of rice lines,with only 16 polymorphic sites,including 22 different alleles.The application of these two backcross introgression rice lines for future study on the mechanisms of heat tolerance in rice at the milky stage will be theoretically beneficial in reducing the interference caused by genetic differences from experimental materials.展开更多
Introgression line population is effectively used in mapping quantitative trait loci（QTLs）,identifying favorable genes,discovering hidden genetic variation,evaluating the action or interaction of QTLs in multiple co...Introgression line population is effectively used in mapping quantitative trait loci（QTLs）,identifying favorable genes,discovering hidden genetic variation,evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research.In this study,an advanced backcross and consecutive selfing strategy was used to develop introgression lines（ILs）,which derived from an accession of Oryza minuta（accession No.101133） with BBCC genome,as the donor,and an elite indica cultivar IR24（O.sativa）,as the recipient.Introgression segments from O.minuta were screened using 164 polymorphic simple sequence repeat（SSR） markers in the genome of each IL.Introgressed segments carried by 131 ILs covered the whole O.sativa genome.The average number of homozygous O.minuta segments per introgression line was about 9.99.The average length of introgressed segments was approximate 14.78 cM,and about 79.64% of these segments had sizes less than 20 cM.In the genome of each introgression line,the O.minuta chromosomal segments harbored chromosomal fragments of O.sativa ranging from 1.15% to 27.6%,with an overall average of 8.57%.At each locus,the ratio of substitution of O.minuta alleles had a range of 1.5% 25.2%,with an average of 8.3%.Based on the evaluation of the phenotype of these ILs,a wide range of alterations in morphological and yield-related traits were found.After inoculation,ILs 41,11 and 7 showed high resistance to bacterial blight,brown planthopper and whitebacked planthopper,respectively.These O.minuta-O.sativa ILs will serve as genetic materials for identifying and using favorable genes from O.minuta.展开更多
To dissect the genetic basis of low phosphorus tolerance （LPT）, 114 BC2F4 introgression lines （ILs） were developed from Shuhui 527 and Minghui 86 （recurrent parents）, and Yetuozai （donor parent）. The progenies...To dissect the genetic basis of low phosphorus tolerance （LPT）, 114 BC2F4 introgression lines （ILs） were developed from Shuhui 527 and Minghui 86 （recurrent parents）, and Yetuozai （donor parent）. The progenies were tested for 11 quantitative traits under three treatments including normal fertilization in normal soil （as control）, normal fertilization in barren soil and low phosphorus stress in barren soil in Langfang, Hebei Province, China. Moreover, the ILs were investigated at the seedling stage using nutrient solution culture method in greenhouse in Beijing, China. A total of 49 main-effect quantitative trait loci （QTLs） underlying yield related traits were identified in Langfang, and their contributions to phenotypic variations ranged from 6.7% to 16.5%. Among them, 25 （51.0%） QTLs had favorable alleles from donor parent. A total of 48 main-effect QTLs were identified for LPT-related traits in Beijing, and their contributions to phenotypic variations ranged from 7.7% to 16.6%. Among them, 21 （43.8%） QTLs had favorable alleles from donor parent. About 79.6% of the QTLs can be detected repeatedly under two or more treatments, especially QTLs associated with spikelet number per panicle, spikelet fertility and 1000-grain weight, displaying consistent phenotypic effects. Among all the detected QTLs, eight QTLs were simultaneously identified under low phosphorus stress across two environments. These results can provide useful information for the genetic dissection of LPT in rice.展开更多
As access to irrigation water becomes increasingly limited, introgression of relevant genomic regions from drought-tolerant wild genotypes is a promising breeding strategy for crop plants. In this study, nine eggplant...As access to irrigation water becomes increasingly limited, introgression of relevant genomic regions from drought-tolerant wild genotypes is a promising breeding strategy for crop plants. In this study, nine eggplant(Solanum melongena) introgression lines(ILs) covering altogether 71.6% of the genome of the donor wildrelative parent S. incanum were evaluated for drought tolerance under water stress conditions. Plants at the five true leaves stage were irrigated at either 100%(control) or 30%(water stress) field capacity for 14 days, and growth and biochemical traits were measured. Reduced irrigation resulted in decreased growth and increased stress markers such as proline and malondialdehyde. Most ILs had lower growth and biomass production thanthe cultivated parent under both conditions. However, the wild alleles for two genomic regions related to stem and root dry weight conferred improved tolerance to water stress. In addition, several S. incanum alleles had a positive effect on important traits that may improve yield under drought conditions, such as leaf water content water use efficiency, and chlorophyll content. Fine-mapping the genomic regions for tolerance and reducinglinkage drag with regions affecting growth will be crucial for significantly improving eggplant drought tolerance through introgression breeding.展开更多
Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multi...Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research. In this study, an advanced backcross and consecutive selfing strategy was used to develop introgression lines （ILs）, which derived from an accession of Oryza rufipogon Griff. collected from Yuanjiang County, Yunnan Province of China, as the donor, and an elite indica cultivar Teqing （O. sativa L.）, as the recipient. Introgression segments from O. rufipogon were screened using 179 polymorphic simple sequence repeats （SSR） markers in the genome of each IL. Introgressed segments carried by the introgression lines population contained 120 ILs covering the whole O. rufipogon genome. The mean number of homozygous O. rufipogon segments per introgression line was about 3.88. The average length of introgressed segments was approximate 25.5 cM, and about 20.8% of these segments had sizes less than 10 cM. The genome of each IL harbored the chromosomal fragments of O. rufipogon ranging from 0.54% to 23.7%, with an overall average of 5.79%. At each locus, the ratio of substitution of O. rufipogon alleles had a range of 1.67-9.33, with an average of 5.50. A wide range of alterations in morphological and yield-related traits were also found in the introgression lines population. Using single-point analysis, a total of 37 putative QTLs for yield and yield components were detected at two sites with 7%-20% explaining the phenotypic variance. Nineteen QTLs （51.4%） were detected at both sites, and the alleles from O. rufipogon at fifteen loci （40.5%） improved the yield and yield components in the Teqing background. These O. rufipogon-O, sativa introgression lines will serve as genetic materials for identifying and using favorable genes from common wild rice.展开更多
In the present study, a set of chromosome segment introgression lines （CSILs） using Gossypium hirsutum L. TM-1 as the recipient parent and G. barbadense Hai7124 as the donor parent were used to explore the genetic b...In the present study, a set of chromosome segment introgression lines （CSILs） using Gossypium hirsutum L. TM-1 as the recipient parent and G. barbadense Hai7124 as the donor parent were used to explore the genetic basis of heterosis for interspecific hybrids. Two sets of F1 populations individually derived from CSILs crossing with both parents were configured to investigate heterotic loci （HL） and substitution effect loci （SL）. A total of 58 HL and 39 SL were identified in 3 years. One stable HL, hLP-A4-3, could be detected in all 3 years. Three HLs, hBS-A8-1, hLP-D6-1, and hSI-D7-11, could be detected in 2 years. Four SLs, sBSoD7- 1, sLP-A8-1, sLP-D7-1, and sLP-D12-1, could be detected in 2 years. HL and SL tended to be distributed in some HL-rich chromosome segments with close positions. Compared with QTL detected in a former study, HL showed little overlap with QTL, indicating that trait phenotype and heterosis might be controlled by different sets of loci. All three forms of genetic effects （partial-, full-, over-dominant） were identified, while the over-dominant effect made the main contribution to heterosis. These results may help lay the foundation for clarifying the heredity mechanism of heterosis in cotton.展开更多
Chromosome segmental introgression lines（ILs）are an effective way to utilize germplasm resources in crops.To improve agronomic traits of wheat cultivar（Triticum aestivum） Shi 4185, four sets of ILs were developed....Chromosome segmental introgression lines（ILs）are an effective way to utilize germplasm resources in crops.To improve agronomic traits of wheat cultivar（Triticum aestivum） Shi 4185, four sets of ILs were developed. The donors were Chinese endemic subspecies accessions Yunnan wheat（T. aestivum ssp. yunnanense） YN3, Tibetan semiwild wheat（T. aestivum ssp. tibetanum） XZ-ZM19450, and Xinjiang wheat（T. aestivum ssp. petropavlovskyi） XJ5, and synthetic wheat HC-XM1620 derived from a cross between T. durum acc. D67.2/P66.270 with Aegilops tauschii acc. 218.Totals of 356, 366, 445 and 457 simple sequence repeat（SSR）markers were polymorphic between Shi 4185 and YN3, XZZM19450, XJ5 and HC-XM1620, respectively. In total, 991 ILs were identified, including 300 derived from YN3, covering 95%of the genome of Shi 4185, 218 from XZ-ZM19450（79%）, 279 from XJ5（97%）, and 194 from HC-ZX1620（84%）. The sizes and locations of each introgression were determined from a consensus SSR linkage map. Using the ILs, 11 putative Resear quantitative trait loci（QTLs） were identified for plant height（PH）, spike length（SL） and grain number per spike（GNS）.Comparative analyses of 24 elite ILs with the parents revealed that the four donor parents could be important resources to improve wheat SL and GNS. Our work offers a case for utilizing endemic landraces for QTL mapping and improvement of wheat cultivars using introgression lines.展开更多
The present study was carried out to illustrate high-efficient detection of quantitative trait loci （QTLs） with selected introgression lines （ILs） and the existence of ＇hidden genes＇ conferring drought tolerance...The present study was carried out to illustrate high-efficient detection of quantitative trait loci （QTLs） with selected introgression lines （ILs） and the existence of ＇hidden genes＇ conferring drought tolerance （DT）. 52 selected DT ILs, derived from BC2Fz population developed by crossing and backcrossing the susceptible recurrent parent （RP） IR64 with the susceptible donor Khazar were planted under irrigation and drought condition. Four important agronomic traits, e.g., grain yield （GY）, heading date （HD）, panicle numbers per plant （PN）, and plant height （PH） were evaluated and 83 SSR polymorphic molecular markers were used for genotypic analysis. Chi-square test based on genetic hitch-hiking and one-way analysis of variances （ANOVA） were used to detect drought-related loci. Nine and 36 loci were detected by chi-square test and one-way ANOVA, respectively. Five common loci were observed by comparing the results of the two methods, among which two QTLs linked with RM7, and RM241 were detected under irrigation condition, both of the favorable alleles were from RP and explained 13% phenotypic variation （PV） for GY and 28% PV for PH, respectively. The other three QTLs linked with RM 163, RM 18, and RM270 were detected under drought condition, the favorable alleles were all from the donor and explained 10, 24, and 19% PV for HD, PH, and PH, respectively. Five common loci were observed by comparing the results of chi-square test and one-way ANOVA including two QTLs （one for GY and one for PH） under irrigation condition and three QTLs （one for HD and two for PH） under drought condition. By combining phenotypic and genotypic analysis, drought escape could be inferred as the main mechanism for drought tolerance in the present study. The results in present study suggested that the selected ILs population analyzed by chi-square test and one-way ANOVA was quite effective for DT QTL detection with low inputs and could also produce useful materials for breeding with wide genetic diversity for drought tolerance.展开更多
Future demands for increased productivity and resilience to abiotic/biotic stresses of major crops require new technologies of breeding by design(BBD)built on massive information from functional and population genomic...Future demands for increased productivity and resilience to abiotic/biotic stresses of major crops require new technologies of breeding by design(BBD)built on massive information from functional and population genomics research.A novel strategy of breeding by selective introgression(BBSI)has been proposed and practiced for simultaneous improvement,genetic dissection and allele mining of complex traits to realize BBD.BBSI has three phases:a)developing large numbers of trait-specific introgression lines(ILs)using backcross breeding in elite genetic backgrounds as the material platform of BBD;b)efficiently identifying genes or quantitative trait loci(QTL)and mining desirable alleles affecting different target traits from diverse donors as the information platform of BBD;and c)developing superior cultivars by BBD using designed QTL pyramiding or marker-assisted recurrent selection.Phase(a)has been implemented massively in rice by many Chinese research institutions and IRRI,resulting in the development of many new green super rice cultivars plus large numbers of ILs in 30+elite genetic backgrounds.Phase(b)has been demonstrated in a series of proof-of-concept studies of high-efficiency genetic dissection of rice yield and tolerance to abiotic stresses using ILs and DNA markers.Phase(c)has also been implemented by designed QTL pyramiding,resulting in a prototype of BBD in several successful cases.The BBSI strategy can be easily extended for simultaneous trait improvement,efficient gene and QTL discovery and allele mining of complex traits using advanced breeding lines from crosses between a common"backbone"parent and a set of elite parents in conventional pedigree breeding programs.BBSI can be relatively easily adopted by breeding programs with small budgets,but the BBSI-based BBD strategy can be fully and more efficiently implemented by large seed companies with sufficient capacity.展开更多
In order to exploit the evolution and find novel low-molecular-weight glutenin subunit （LMW-GS） for improvement of common wheat quality, thirteen variants from a somatic hybrid introgression line II-12 between Triti...In order to exploit the evolution and find novel low-molecular-weight glutenin subunit （LMW-GS） for improvement of common wheat quality, thirteen variants from a somatic hybrid introgression line II-12 between Triticum aestivum cv. Jinan 177 （JN177） and Agropyron elongatum were characterized via genomic PCR. Four clones were pseudogenes because they contained an internal stop codon. The remaining nine variants contained intact open reading frames （ORFs）. Sequence alignment indicates that the proteins deduced from the nine ORFs have similar primary structure with LMW-GS cloned from its parents previously. However, they have some unique modifications in the structures. For example, EU292737 contains not only an extra Cys residue in the C-terminal domain but also a long repetitive domain. Both EU 159511 and EU292738 start their first Cys residue in the N-terminal repetitive domain, but not in the N-conserved domain traditionally. These structural alterations may have positive contributions to wheat flour quality. The results of phylogeny showed that most LMW-GS variances from 11-12 were homologous to those from parent JN177 and other wheat lines. The reason for quick evolution of LMW-GS in 11-12 was discussed.展开更多
The main cultivated varieties in the world belong to the species of upland cotton(Gossypium hirsutum L.),and their genetic background is very narrow.However,the wild species and races in
The wild cotton cultivars and species have abundant genetic polymorphisms,and they possess lots of excellent genes,such as drought resistance,insect resistance,fine and strong fiber,and so on.
Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were der...Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were derived from a cross between an elite indica cultivar Teqing and an accession of common wild rice（Oryza rufipogon Griff.）.Substantial variation was observed for four traits including salt tolerance score（STS）, relative root dry weight（RRW）,relative shoot dry weight（RSW） and relative total dry weight（RTW）.STS was significantly positively correlated with all other three traits.A total of 15 putative quantitative trait loci（QTLs） associated with these four traits were detected using single-point analysis,which were located on chromosomes 1,2,3,6,7,9 and 10 with 8%-26%explaining the phenotypic variance.The O. rufipogon-derived alleles at 13 QTLs（86.7%） could improve the salt tolerance in the Teqing background.Four QTL clusters affecting RRW, RSW and RTW were found on chromosomes 6,7,9 and 10,respectively.Among these four QTL clusters,a major cluster including three QTLs （qRRWIO,qRSWIO and qRTWIO） was found near the maker RM271 on the long arm of chromosome 10,and the O.rufipogon-derived alleles at these three loci increased RRW,RSW and RTW with additive effects of 22.7%,17.3%and 18.5%,respectively,while the phenotypic variance explained by these three individual QTLs for the three traits varied from 19%to 26%.In addition,several salt tolerant ILs were selected and could be used for identifying and utilizing favorable salt tolerant genes from common wild rice and used in the salt tolerant rice breeding program.展开更多
基金funded by the National Key Research and Development Program of China(2016YFD0100203 and 2016YFD0102000)the Key Scientific and Technological Projects of the Eighth Division of the Xinjiang Production and Construction Corps(XPCC),China(2024NY01,2023 NY09,2023 NY10)+2 种基金the Key Scientific and Technological Project of XPCC,China(2021AB010)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_0748)supported by the High-performance Computing Platform of the Bioinformatics Center,Nanjing Agricultural University,China。
文摘Gossypium raimondii(2n=2x=26,D_(5)),an untapped wild species,is the putative progenitor of the D-subgenome of G.hirsutum(2n=4x=52,AD_(1)),an extensively cultivated species.Here,we developed a G.hirsutum(recipient)–G.raimondii(donor)introgression population to exploit the favorable QTLs/genes and mapped potential quantitative trait loci(QTLs)from wild cotton species.The introgression population consisted of 256 lines with an introgression rate of 52.33%for the G.raimondii genome.The introgression segment length range was 0.03–19.12 Mb,with an average of 1.22 Mb.The coverage of total introgression fragments from G.raimondii was 386.98 Mb.Further genome-wide association analysis(Q+K+MLM)and QTL mapping(RSTEP-LRT)identified 59 common QTLs,including 14 stable QTLs and six common QTL(co-QTL)clusters,and one hotspot of micronaire(MIC).The common QTLs for seed index all showed positive additive effects,while the common QTLs for boll weight all had negative additive effects,indicating that the linkage between seed index and boll weight could be broken.QTLs for lint percentage showed positive effects and could be beneficial for improving cotton yield.Most QTLs for fiber quality had negative additive effects,implying these QTLs were domesticated/improved in G.hirsutum.A few fiber quality QTLs showed positive additive effects,so they could be used to improve cotton fiber quality.The introgression lines developed could be useful for molecular marker-assisted breeding and mapping QTLs precisely for mining desirable genes from the wild species G.raimondii.Such genes can improve cultivated cotton in the future through a designbreeding approach.
基金supported by the Hi-Tech Research and Development Program of China (No. 2006AA10Z158 and No. 2006AA100101)the "948" Project (No. 2006-G1)+1 种基金China National Key Technologies R & D Program (No. 2006BAD13B01-6)the Program for Chang Jiang Scholars and Innovative Research Team in University, Program of Introducing Talents of Discipline to Universi-ties in China (111-2-03).
文摘Phosphorous （P） deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines （ILs） were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length （MRL） and root-shoot ratio （RS） were induced by P-deficiency stress. Relative MRL （RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency con- dition） and relative RS （RRS） were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits （RMRL, RRS, RRV, and RRDW） and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL （qRRSS） showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.
基金partially supported by National Natural Science Foundation of China(30860120,30900781)Science and Technology Projects of Jiangxi Education Department(GJJ09464)Natural Science Foundation of Jiangxi(2008GQN0059)~~
文摘[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.
基金funded by the National Basic Research Program of China(No.2010CB1125904)the National Key Technologies R&D Program of China(No.2009BADA2B01)+2 种基金the National Natural Science Foundation of China(No. 31061140458)"948"Project of MOA(No.2011-G2B)the Key Project of Transgenic Crop Improvement of China (No.2009ZX08009-073B)
文摘Introgression lines （ILs） are valuable materials for identifying quantitative trait loci （QTLs）, evaluating genetic interactions, and marker assisted breeding. A set of 430 ILs （BC5F3） containing segments from upland tropical japonica cultivar IRAT109 in a lowland temperate japonica cultivar Yuefu background were developed. One hundred and seventy-six polymorphic markers were used to identify introgressed segments. No segment from IRAT109 was found in 160 lines. Introgressed segments of the other 270 lines covered 99.1% of the donor genome. The mean number of introgressed donor segments per individual was 3.3 with an average length of 14.4 cM. QTL analysis was conducted on basal root thickness （BRT） of the 270 ILs grown under irrigated lowland, upland and hydroponic conditions. A total of 22 QTLs affecting BRT were identified, six QTLs （qBRT3.1, qBRT3.2, qBRT6.1, qBRTS.2, qBRT9.1, and qBRT9.2） were consistently expressed under at least two environments （location and water regime）, and qBRT7.2 was a new BRT QTL identified under lowland conditions. IL255 containing qBRT9.1 showed an increase of 10.09% and 7.07% BRT over cultivar Yuefu when grown under upland and lowland conditions, respectively. Using a population of 304 F2：3 lines derived from the cross IL255 Yuefu, qBRT9.1 was validated and mapped to a 1.2 cM interval between RM24271 and RM566. The presence of qBRT9.1 explained 12% of BRT variation. The results provide upland rice ILs and BRT QTLs for analyzing the genetic basis of drought resistance, detecting favorable genes from upland rice, and rice drought resistance breeding.
基金funded by the National High Technology Research and Development Program of China (No.2014AA10A604)the Shenzhen Municipal Peacock Plan for introducing high-level overseas talents
文摘Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis of heterosis for yield and eight related traits.Four testcross(TC) populations with 228 testcross F1 combinations were developed by crossing57 introgression lines with four types of widely used male sterile lines using a North Carolina II mating design.Analysis of variance indicated that the effects of testcross F1 combinations and their parents were significant or highly significant for most of the traits in both years,and all interaction effects with year were significant for most of the traits.Positive midparent heterosis(HMP) was observed for most traits in the four TC populations in the two years.The relative HMPlevels for most traits varied from highly negative to highly positive.Sixty-two dominant-effect QTL were identified for HMPof the nine traits in the four TC populations in the two years.Of these,22 QTL were also identified for the performance of testcross F1.Most dominant-effect QTL could individually explain more than 10% of the phenotypic variation.Four QTL clusters were observed including the region surrounding the RM9–RM297 region on chromosome 1,the RM110–RM279–RM8–RM5699–RM452 region on chromosome 2,the RM5463 locus on chromosome 6 and the RM1146–RM147 region on chromosome 10.The identified QTL for heterosis provide valuable information for dissecting the genetic basis of heterosis.
文摘Wild relatives possess potential genetic diversity for maize (<i><span style="font-family:Verdana;">Zea mays</span></i><span style="font-family:Verdana;"> L.) improvement. Characterization of maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> introgression lines (ILs) is of great value to diversify the genetic base and improve the maize germplasm. Four maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> IL generations, </span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;"> BC1, BC2, BC3, and RIL, were constructed under the elite inbred background of 48-2, elite inbred line that is widely used in maize breeding in Southwestern China, and were phenotyped in different years and genotyped with 56110 SNPs. The results indicated that 48-2 had higher phenotypic performances than all the characterized ILs on most of the agronomic traits. Compared with other ILs, BC2 individuals exhibited more similar performance to 48-2 on most traits and possessed the highest kernel ratio (66.5%). Population structure and principal component analysis indicated that BC3 individuals gathered closer to 48-2 and exhibited the lowest </span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;">-introgression frequency (0.50%), while BC2 (29.06%) and RIL (18.52%) showed higher introgression frequency. The high level of genetic diversity observed in the maize-</span><i><span style="font-family:Verdana;">mexicana</span></i><span style="font-family:Verdana;"> ILs demonstrated that </span><i><span style="font-family:Verdana;">Z</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">mays</span></i><span style="font-family:Verdana;"> ssp. </span><i><span style="font-family:Verdana;">mexicana </span></i><span style="font-family:Verdana;">can serve as a potential source for the enrichment of maize germplasm.</span>
基金supported by the National Natural Science Foundation of China(Grant No.30671230)the Natural Science Foundation of Jiangxi Province,China(Grant No.2007GZN0253)
文摘The present study aimed at breeding new rice germplasms with similar genome but significantly differed in heat tolerance during the grain filling stage.A total of 791 BC1F8 backcross recombinant lines,derived from the cross of Xieqingzao B /N22 //Xieqingzao B,were used as materials.Each rice line was separated evenly into two groups,and the heat tolerance of all rice lines were evaluated at natural high temperature in fields.The rice lines with heat tolerant index higher than 90% or lower than 40% were selected to compare the phenotypic characters and further identify heat tolerance at the early milky stage in a phytotron.Rice lines with similar phenotypic characters but significantly differed in heat tolerance at the milky stage were analyzed by 887 simple sequence repeat markers that were evenly distributed on the 12 rice chromosomes.In the result,12(6 pairs) rice lines with similar phenotypic characters but significantly differed in heat tolerance at the milky stage were obtained.Molecular marker analysis indicated that the genomic polymorphism between 703T and 704S was the smallest in the 6 pairs of rice lines,with only 16 polymorphic sites,including 22 different alleles.The application of these two backcross introgression rice lines for future study on the mechanisms of heat tolerance in rice at the milky stage will be theoretically beneficial in reducing the interference caused by genetic differences from experimental materials.
基金supported by grants from the National Natural Science Foundation of China (Grant No.31160277)the Ministry of Science and Technology of China (Grant No. 2010AA101803)+2 种基金the Ministry of Agriculture of China (Grant No. 2011ZX08001-001)the Guangxi Science and Technology Department,China (Grant No. 10100005-8,2012GXNSFAA053056)the Guangxi Academy of Agricultural Sciences,China (Grant No. 2011JZ02 2011JM02,12-071-09)
文摘Introgression line population is effectively used in mapping quantitative trait loci（QTLs）,identifying favorable genes,discovering hidden genetic variation,evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research.In this study,an advanced backcross and consecutive selfing strategy was used to develop introgression lines（ILs）,which derived from an accession of Oryza minuta（accession No.101133） with BBCC genome,as the donor,and an elite indica cultivar IR24（O.sativa）,as the recipient.Introgression segments from O.minuta were screened using 164 polymorphic simple sequence repeat（SSR） markers in the genome of each IL.Introgressed segments carried by 131 ILs covered the whole O.sativa genome.The average number of homozygous O.minuta segments per introgression line was about 9.99.The average length of introgressed segments was approximate 14.78 cM,and about 79.64% of these segments had sizes less than 20 cM.In the genome of each introgression line,the O.minuta chromosomal segments harbored chromosomal fragments of O.sativa ranging from 1.15% to 27.6%,with an overall average of 8.57%.At each locus,the ratio of substitution of O.minuta alleles had a range of 1.5% 25.2%,with an average of 8.3%.Based on the evaluation of the phenotype of these ILs,a wide range of alterations in morphological and yield-related traits were found.After inoculation,ILs 41,11 and 7 showed high resistance to bacterial blight,brown planthopper and whitebacked planthopper,respectively.These O.minuta-O.sativa ILs will serve as genetic materials for identifying and using favorable genes from O.minuta.
基金funded by the National High-Technology Research and Development Program of China (Grant No.2014AA10A604)Shenzhen Peacock Plan in China
文摘To dissect the genetic basis of low phosphorus tolerance （LPT）, 114 BC2F4 introgression lines （ILs） were developed from Shuhui 527 and Minghui 86 （recurrent parents）, and Yetuozai （donor parent）. The progenies were tested for 11 quantitative traits under three treatments including normal fertilization in normal soil （as control）, normal fertilization in barren soil and low phosphorus stress in barren soil in Langfang, Hebei Province, China. Moreover, the ILs were investigated at the seedling stage using nutrient solution culture method in greenhouse in Beijing, China. A total of 49 main-effect quantitative trait loci （QTLs） underlying yield related traits were identified in Langfang, and their contributions to phenotypic variations ranged from 6.7% to 16.5%. Among them, 25 （51.0%） QTLs had favorable alleles from donor parent. A total of 48 main-effect QTLs were identified for LPT-related traits in Beijing, and their contributions to phenotypic variations ranged from 7.7% to 16.6%. Among them, 21 （43.8%） QTLs had favorable alleles from donor parent. About 79.6% of the QTLs can be detected repeatedly under two or more treatments, especially QTLs associated with spikelet number per panicle, spikelet fertility and 1000-grain weight, displaying consistent phenotypic effects. Among all the detected QTLs, eight QTLs were simultaneously identified under low phosphorus stress across two environments. These results can provide useful information for the genetic dissection of LPT in rice.
基金supported by the grants CIPROM/2021/020 from Conselleria d’Educació, Universitats i Ocupació (Generalitat Valenciana, Spain)PID2021-128148OB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by “ERDF A way of making Europ”, as well as by the initiative “Adapting Agriculture to Climate Change: Collecting, Protecting and Preparing Crop Wild Relatives” supported by the Government of Norway+1 种基金Conselleria d’Educació, Universitats i Ocupació de la Generalitat Valenciana for a pre-doctoral grant within the Santiago Grisolía programme (GRISOLIAP/2021/151)Spanish Ministerio de Ciencia e Innovación for a postdoctoral grant (RYC2021-031999-I) funded by MCIN/ AEI/10.13039/501100011033 and the European Union through NextG enerationE U/PRTR。
文摘As access to irrigation water becomes increasingly limited, introgression of relevant genomic regions from drought-tolerant wild genotypes is a promising breeding strategy for crop plants. In this study, nine eggplant(Solanum melongena) introgression lines(ILs) covering altogether 71.6% of the genome of the donor wildrelative parent S. incanum were evaluated for drought tolerance under water stress conditions. Plants at the five true leaves stage were irrigated at either 100%(control) or 30%(water stress) field capacity for 14 days, and growth and biochemical traits were measured. Reduced irrigation resulted in decreased growth and increased stress markers such as proline and malondialdehyde. Most ILs had lower growth and biomass production thanthe cultivated parent under both conditions. However, the wild alleles for two genomic regions related to stem and root dry weight conferred improved tolerance to water stress. In addition, several S. incanum alleles had a positive effect on important traits that may improve yield under drought conditions, such as leaf water content water use efficiency, and chlorophyll content. Fine-mapping the genomic regions for tolerance and reducinglinkage drag with regions affecting growth will be crucial for significantly improving eggplant drought tolerance through introgression breeding.
基金Supported by the Project of Conservation and Utilization of Agricultural Wild Plants of the Ministry of Agriculture of China and a Grant from High- Tech Research and Development （863） Program of China （2006AA100101 ）, and the National Natural Science Foundation of China （30270803）. Publication of this paper is supported by the National Natural Science Foundation of China （30624808）.
文摘Introgression lines population was effectively used in mapping quantitative trait loci （QTLs）, identifying favorable genes, discovering hidden genetic variation, evaluating the action or interaction of QTLs in multiple conditions and providing the favorable experimental materials for plant breeding and genetic research. In this study, an advanced backcross and consecutive selfing strategy was used to develop introgression lines （ILs）, which derived from an accession of Oryza rufipogon Griff. collected from Yuanjiang County, Yunnan Province of China, as the donor, and an elite indica cultivar Teqing （O. sativa L.）, as the recipient. Introgression segments from O. rufipogon were screened using 179 polymorphic simple sequence repeats （SSR） markers in the genome of each IL. Introgressed segments carried by the introgression lines population contained 120 ILs covering the whole O. rufipogon genome. The mean number of homozygous O. rufipogon segments per introgression line was about 3.88. The average length of introgressed segments was approximate 25.5 cM, and about 20.8% of these segments had sizes less than 10 cM. The genome of each IL harbored the chromosomal fragments of O. rufipogon ranging from 0.54% to 23.7%, with an overall average of 5.79%. At each locus, the ratio of substitution of O. rufipogon alleles had a range of 1.67-9.33, with an average of 5.50. A wide range of alterations in morphological and yield-related traits were also found in the introgression lines population. Using single-point analysis, a total of 37 putative QTLs for yield and yield components were detected at two sites with 7%-20% explaining the phenotypic variance. Nineteen QTLs （51.4%） were detected at both sites, and the alleles from O. rufipogon at fifteen loci （40.5%） improved the yield and yield components in the Teqing background. These O. rufipogon-O, sativa introgression lines will serve as genetic materials for identifying and using favorable genes from common wild rice.
基金supported by grants from the Shandong Province System of Modern Agriculture Industrial Technology(Cotton industry)the Science and Technology Development Project of Shandong Province (2012GGB01026)the Shandong Agricultural Breeding Project(2010LZ005-01)
文摘In the present study, a set of chromosome segment introgression lines （CSILs） using Gossypium hirsutum L. TM-1 as the recipient parent and G. barbadense Hai7124 as the donor parent were used to explore the genetic basis of heterosis for interspecific hybrids. Two sets of F1 populations individually derived from CSILs crossing with both parents were configured to investigate heterotic loci （HL） and substitution effect loci （SL）. A total of 58 HL and 39 SL were identified in 3 years. One stable HL, hLP-A4-3, could be detected in all 3 years. Three HLs, hBS-A8-1, hLP-D6-1, and hSI-D7-11, could be detected in 2 years. Four SLs, sBSoD7- 1, sLP-A8-1, sLP-D7-1, and sLP-D12-1, could be detected in 2 years. HL and SL tended to be distributed in some HL-rich chromosome segments with close positions. Compared with QTL detected in a former study, HL showed little overlap with QTL, indicating that trait phenotype and heterosis might be controlled by different sets of loci. All three forms of genetic effects （partial-, full-, over-dominant） were identified, while the over-dominant effect made the main contribution to heterosis. These results may help lay the foundation for clarifying the heredity mechanism of heterosis in cotton.
基金sponsored by the Ministry of Science and Technology of China(2013BAD01B02)the National Science and Technology Major Project of China(2009ZX08009010)
文摘Chromosome segmental introgression lines（ILs）are an effective way to utilize germplasm resources in crops.To improve agronomic traits of wheat cultivar（Triticum aestivum） Shi 4185, four sets of ILs were developed. The donors were Chinese endemic subspecies accessions Yunnan wheat（T. aestivum ssp. yunnanense） YN3, Tibetan semiwild wheat（T. aestivum ssp. tibetanum） XZ-ZM19450, and Xinjiang wheat（T. aestivum ssp. petropavlovskyi） XJ5, and synthetic wheat HC-XM1620 derived from a cross between T. durum acc. D67.2/P66.270 with Aegilops tauschii acc. 218.Totals of 356, 366, 445 and 457 simple sequence repeat（SSR）markers were polymorphic between Shi 4185 and YN3, XZZM19450, XJ5 and HC-XM1620, respectively. In total, 991 ILs were identified, including 300 derived from YN3, covering 95%of the genome of Shi 4185, 218 from XZ-ZM19450（79%）, 279 from XJ5（97%）, and 194 from HC-ZX1620（84%）. The sizes and locations of each introgression were determined from a consensus SSR linkage map. Using the ILs, 11 putative Resear quantitative trait loci（QTLs） were identified for plant height（PH）, spike length（SL） and grain number per spike（GNS）.Comparative analyses of 24 elite ILs with the parents revealed that the four donor parents could be important resources to improve wheat SL and GNS. Our work offers a case for utilizing endemic landraces for QTL mapping and improvement of wheat cultivars using introgression lines.
基金funded by the National Basic Research Program of China (973 Program, 2004CB117204)the Program for Introduction of International Advanced Ag-ricultural Sciences & Technologies from the Ministry of Agriculture of China [948 Progam, 2006-G1(A)]the Project of Rockefeller Foundation, USA (RF2000)
文摘The present study was carried out to illustrate high-efficient detection of quantitative trait loci （QTLs） with selected introgression lines （ILs） and the existence of ＇hidden genes＇ conferring drought tolerance （DT）. 52 selected DT ILs, derived from BC2Fz population developed by crossing and backcrossing the susceptible recurrent parent （RP） IR64 with the susceptible donor Khazar were planted under irrigation and drought condition. Four important agronomic traits, e.g., grain yield （GY）, heading date （HD）, panicle numbers per plant （PN）, and plant height （PH） were evaluated and 83 SSR polymorphic molecular markers were used for genotypic analysis. Chi-square test based on genetic hitch-hiking and one-way analysis of variances （ANOVA） were used to detect drought-related loci. Nine and 36 loci were detected by chi-square test and one-way ANOVA, respectively. Five common loci were observed by comparing the results of the two methods, among which two QTLs linked with RM7, and RM241 were detected under irrigation condition, both of the favorable alleles were from RP and explained 13% phenotypic variation （PV） for GY and 28% PV for PH, respectively. The other three QTLs linked with RM 163, RM 18, and RM270 were detected under drought condition, the favorable alleles were all from the donor and explained 10, 24, and 19% PV for HD, PH, and PH, respectively. Five common loci were observed by comparing the results of chi-square test and one-way ANOVA including two QTLs （one for GY and one for PH） under irrigation condition and three QTLs （one for HD and two for PH） under drought condition. By combining phenotypic and genotypic analysis, drought escape could be inferred as the main mechanism for drought tolerance in the present study. The results in present study suggested that the selected ILs population analyzed by chi-square test and one-way ANOVA was quite effective for DT QTL detection with low inputs and could also produce useful materials for breeding with wide genetic diversity for drought tolerance.
基金funded by the National Key Research&Development Program of China(2017YFD0100100)Key-Area Research&Development Program of Guangdong Province(2020B020219004)+2 种基金Shenzhen Basic Research Special Project(2020231601)Agricultural Science and Technology Innovation Programthe Cooperation and Innovation Mission(CAAS2021-01)。
文摘Future demands for increased productivity and resilience to abiotic/biotic stresses of major crops require new technologies of breeding by design(BBD)built on massive information from functional and population genomics research.A novel strategy of breeding by selective introgression(BBSI)has been proposed and practiced for simultaneous improvement,genetic dissection and allele mining of complex traits to realize BBD.BBSI has three phases:a)developing large numbers of trait-specific introgression lines(ILs)using backcross breeding in elite genetic backgrounds as the material platform of BBD;b)efficiently identifying genes or quantitative trait loci(QTL)and mining desirable alleles affecting different target traits from diverse donors as the information platform of BBD;and c)developing superior cultivars by BBD using designed QTL pyramiding or marker-assisted recurrent selection.Phase(a)has been implemented massively in rice by many Chinese research institutions and IRRI,resulting in the development of many new green super rice cultivars plus large numbers of ILs in 30+elite genetic backgrounds.Phase(b)has been demonstrated in a series of proof-of-concept studies of high-efficiency genetic dissection of rice yield and tolerance to abiotic stresses using ILs and DNA markers.Phase(c)has also been implemented by designed QTL pyramiding,resulting in a prototype of BBD in several successful cases.The BBSI strategy can be easily extended for simultaneous trait improvement,efficient gene and QTL discovery and allele mining of complex traits using advanced breeding lines from crosses between a common"backbone"parent and a set of elite parents in conventional pedigree breeding programs.BBSI can be relatively easily adopted by breeding programs with small budgets,but the BBSI-based BBD strategy can be fully and more efficiently implemented by large seed companies with sufficient capacity.
基金supported by the National High Technology Research and Development Program(No.2006AA10Z173 and 2006011001020)the Natural Science Foundation of Shandong Province(Y2007D48)
文摘In order to exploit the evolution and find novel low-molecular-weight glutenin subunit （LMW-GS） for improvement of common wheat quality, thirteen variants from a somatic hybrid introgression line II-12 between Triticum aestivum cv. Jinan 177 （JN177） and Agropyron elongatum were characterized via genomic PCR. Four clones were pseudogenes because they contained an internal stop codon. The remaining nine variants contained intact open reading frames （ORFs）. Sequence alignment indicates that the proteins deduced from the nine ORFs have similar primary structure with LMW-GS cloned from its parents previously. However, they have some unique modifications in the structures. For example, EU292737 contains not only an extra Cys residue in the C-terminal domain but also a long repetitive domain. Both EU 159511 and EU292738 start their first Cys residue in the N-terminal repetitive domain, but not in the N-conserved domain traditionally. These structural alterations may have positive contributions to wheat flour quality. The results of phylogeny showed that most LMW-GS variances from 11-12 were homologous to those from parent JN177 and other wheat lines. The reason for quick evolution of LMW-GS in 11-12 was discussed.
文摘The main cultivated varieties in the world belong to the species of upland cotton(Gossypium hirsutum L.),and their genetic background is very narrow.However,the wild species and races in
文摘The wild cotton cultivars and species have abundant genetic polymorphisms,and they possess lots of excellent genes,such as drought resistance,insect resistance,fine and strong fiber,and so on.
基金supported by the Project of Conservation and Utilization of Agro-Wild Plants of the Ministry of Agriculture of China and Special Fund for Agro-scientific Research in the Public Interest(No.201003021)
文摘Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were derived from a cross between an elite indica cultivar Teqing and an accession of common wild rice（Oryza rufipogon Griff.）.Substantial variation was observed for four traits including salt tolerance score（STS）, relative root dry weight（RRW）,relative shoot dry weight（RSW） and relative total dry weight（RTW）.STS was significantly positively correlated with all other three traits.A total of 15 putative quantitative trait loci（QTLs） associated with these four traits were detected using single-point analysis,which were located on chromosomes 1,2,3,6,7,9 and 10 with 8%-26%explaining the phenotypic variance.The O. rufipogon-derived alleles at 13 QTLs（86.7%） could improve the salt tolerance in the Teqing background.Four QTL clusters affecting RRW, RSW and RTW were found on chromosomes 6,7,9 and 10,respectively.Among these four QTL clusters,a major cluster including three QTLs （qRRWIO,qRSWIO and qRTWIO） was found near the maker RM271 on the long arm of chromosome 10,and the O.rufipogon-derived alleles at these three loci increased RRW,RSW and RTW with additive effects of 22.7%,17.3%and 18.5%,respectively,while the phenotypic variance explained by these three individual QTLs for the three traits varied from 19%to 26%.In addition,several salt tolerant ILs were selected and could be used for identifying and utilizing favorable salt tolerant genes from common wild rice and used in the salt tolerant rice breeding program.
