scholarly journals A new advanced backcross tomato population enables high resolution leaf QTL mapping and gene identification

2016 ◽  
Author(s):  
Daniel Fulop ◽  
Aashish Ranjan ◽  
Itai Ofner ◽  
Michael F. Covington ◽  
Daniel H. Chitwood ◽  
...  
Keyword(s):  
Qtl Mapping ◽  
Fine Mapping ◽  
Introgression Line ◽  
Recurrent Parent ◽  
Isogenic Line ◽  
Solanum Pennellii ◽  
Tomato Cultivar ◽  
Advanced Backcross ◽  
Regression Techniques ◽  
Trait Locus

ABSTRACTQuantitative Trait Locus (QTL) mapping is a powerful technique for dissecting the genetic basis of traits and species differences. Established tomato mapping populations between domesticated tomato (Solanum lycopersicum) and its more distant interfertile relatives typically follow a near isogenic line (NIL) design, such as the Solanum pennellii Introgression Line (IL) population, with a single wild introgression per line in an otherwise domesticated genetic background. Here we report on a new advanced backcross QTL mapping resource for tomato, derived from a cross between the M82 tomato cultivar and S. pennelli. This so-called Backcrossed Inbred Line (BIL) population is comprised of a mix of BC2 and BC3 lines, with domesticated tomato as the recurrent parent. The BIL population is complementary to the existing S. pennellii IL population, with which it shares parents. Using the BILs we mapped traits for leaf complexity, leaflet shape, and flowering time. We demonstrate the utility of the BILs for fine-mapping QTL, particularly QTL initially mapped in the ILs, by fine-mapping several QTL to single or few candidate genes. Moreover, we confirm the value of a backcrossed population with multiple introgressions per line, such as the BILs, for epistatic QTL mapping. Our work was further enabled by the development of our own statistical inference and visualization tools, namely a heterogeneous Hidden Markov Model for genotyping the lines, and by using state of the art sparse regression techniques for QTL mapping.

Validation of QTLs associated with spikelets per panicle and grain weight in rice

2014 ◽  
Vol 12 (S1) ◽  
pp. S151-S154 ◽  
Author(s):  
Sang-Min Yeo ◽  
Yeo-Tae Yun ◽  
Dong-Min Kim ◽  
Chong-Tae Chung ◽  
Sang-Nag Ahn
Keyword(s):  
Oryza Rufipogon ◽  
Grain Weight ◽  
Chromosome 1 ◽  
Recurrent Parent ◽  
Phenotypic Variance ◽  
Isogenic Line ◽  
Substitution Mapping ◽  
Spikelets Per Panicle ◽  
Breeding Programmes ◽  
Trait Locus

In this study, a near-isogenic line (BC4F10) CR572 developed by introgressing a chromosomal segment from Oryza rufipogon (accession no. 105491) into the Oryza sativa subsp. japonica cv. Hwaseong was found to exhibit a significant increase in the number of spikelets per panicle (SPP) and grain weight compared with the recurrent parent Hwaseong. Quantitative trait locus (QTL) analysis in F2 generation derived from the cross between CR572 and Hwaseong revealed that two QTLs, qSPP1 and qTGW1, were linked to a simple sequence repeat marker, RM283, on chromosome 1. The additive effect of the O. rufipogon allele at qSPP1 was 13 SPP, and 21.6% of the phenotypic variance was explained by the segregation of RM283. The qTGW1 QTL explained 19.1% of the phenotypic variance for grain weight. Substitution mapping was carried out with five F3 lines derived from F2 plants having informative recombination breakpoints within the target region. Substitution mapping indicated the linkage of qSPP1 and qTGW1. The grain yield of CR572 was 18.2 and 15.8% higher than that of Hwaseong at two locations, respectively, mainly due to the increase in 1000-grain weight and SPP. These results are very useful for QTL cluster transfer by molecular marker-assisted selection in rice breeding programmes and for QTL gene cloning by map-based cloning.

scholarly journals Verification and dissection of one quantitative trait locus for grain size and weight on chromosome 1 in rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi-chen Cheng ◽  
Guan Li ◽  
Man Yin ◽  
Tosin Victor Adegoke ◽  
Yi-feng Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Quantitative Trait ◽  
Genetic Background ◽  
Molecular Design ◽  
Chromosome 1 ◽  
Recurrent Parent ◽  
Isogenic Line ◽  
Growing Seasons ◽  
Ril Population ◽  
Trait Locus

AbstractGrain size and weight are the key traits determining rice quality and yield and are mainly controlled by quantitative trait loci (QTL). In this study, one minor QTL that was previously mapped in the marker interval of JD1009-JD1019 using the Huanghuazhan/Jizi1560 (HHZ/JZ1560) recombinant inbred line (RIL) population, qTGW1-2, was validated to regulate grain size and weight across four rice-growing seasons using twenty-one near isogenic line (NIL)-F2 populations. The twenty-one populations were in two types of genetic background that were derived from the same parents HHZ and JZ1560. Twelve F9, F10 or F11 NIL-F2 populations with the sequential residual heterozygous regions covering JD1009-RM6840 were developed from one residual heterozygote (RH) in the HHZ/JZ1560 RIL population, and the remaining nine BC3F3, BC3F4 or BC3F5 NIL-F2 populations with the sequential residual heterozygous regions covering JD1009-RM6840 were constructed through consecutive backcrosses to the recurrent parent HHZ followed with marker assistant selection in each generation. Based on the QTL analysis of these genetic populations, qTGW1-2 was successfully confirmed to control grain length, width and weight and further dissected into two QTLs, qTGW1-2a and qTGW1-2b, which were respectively narrowed down to the marker intervals of JD1139-JD1127 (~ 978.2-kb) and JD1121-JD1102 (~ 54.8-kb). Furthermore, the two types of NIL-F2 populations were proved to be able to decrease the genetic background noise and increase the detection power of minor QTL. These results provided an important basis for further map-based cloning and molecular design breeding with the two QTLs in rice.

scholarly journals Consequences of Recombination Rate Variation on Quantitative Trait Locus Mapping Studies: Simulations Based on the Drosophila melanogaster Genome

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 581-588
Author(s):  
Mohamed A F Noor ◽  
Aimee L Cunningham ◽  
John C Larkin
Keyword(s):  
Quantitative Trait Locus ◽  
Drosophila Melanogaster ◽  
Qtl Mapping ◽  
Quantitative Trait ◽  
Recombination Rate ◽  
Genome Project ◽  
Gene Density ◽  
Rate Variation ◽  
Trait Locus ◽  
Recombination Rate Variation

Abstract We examine the effect of variation in gene density per centimorgan on quantitative trait locus (QTL) mapping studies using data from the Drosophila melanogaster genome project and documented regional rates of recombination. There is tremendous variation in gene density per centimorgan across this genome, and we observe that this variation can cause systematic biases in QTL mapping studies. Specifically, in our simulated mapping experiments of 50 equal-effect QTL distributed randomly across the physical genome, very strong QTL are consistently detected near the centromeres of the two major autosomes, and few or no QTL are often detected on the X chromosome. This pattern persisted with varying heritability, marker density, QTL effect sizes, and transgressive segregation. Our results are consistent with empirical data collected from QTL mapping studies of this species and its close relatives, and they explain the “small X-effect” that has been documented in genetic studies of sexual isolation in the D. melanogaster group. Because of the biases resulting from recombination rate variation, results of QTL mapping studies should be taken as hypotheses to be tested by additional genetic methods, particularly in species for which detailed genetic and physical genome maps are not available.

Uncovering tomato candidate genes for seed germination performance and seedling vigour using the Solanum pennellii introgression line population

2021 ◽  
Vol 284 ◽  
pp. 110134
Author(s):  
Herika Paula Pessoa ◽  
Laércio Junio Da Silva ◽  
Rafael Ravanelli Chagas ◽  
Mariane Gonçalves Ferreira Copati ◽  
Françoise Dalprá Dariva ◽  
...  
Keyword(s):  
Seed Germination ◽  
Candidate Genes ◽  
Introgression Line ◽  
Solanum Pennellii ◽  
Seedling Vigour

Transcriptome analysis reveals genes potentially related to high fiber strength in a Gossypium hirsutum line IL9 with Gossypium mustelinum introgression

Genome ◽  
2021 ◽  
pp. 1-11
Author(s):  
Qi Chen ◽  
Wei Wang ◽  
Sameer Khanal ◽  
Jinlei Han ◽  
Mi Zhang ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Fiber Strength ◽  
Fiber Quality ◽  
Enrichment Analysis ◽  
Introgression Line ◽  
Recurrent Parent ◽  
High Fiber ◽  
Go Enrichment ◽  
Annotation Information ◽  
Cotton Fiber Quality

Cotton (Gossypium L.) is the most important fiber crop worldwide. Here, transcriptome analysis was conducted on developing fibers of a G. mustelinum introgression line, IL9, and its recurrent parent, PD94042, at 17 and 21 days post-anthesis (dpa). Differentially expressed genes (DEGs) of PD94042 and IL9 were identified. Gene Ontology (GO) enrichment analysis showed that the annotated DEGs were rich in two main biological processes and two main molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis likewise showed that the annotated DEGs were mainly enriched in metabolic pathways and biosynthesis of secondary metabolites. In total, 52 DEGs were selected as candidate genes based on comparison of the DEGs and GO function annotation information. Quantitative real-time PCR (RT-qPCR) analysis results for 12 randomly selected DEGs were consistent with transcriptome analysis. SNP identification based on G. mustelinum chromatin segment introgression showed that 394 SNPs were identified in 268 DEGs, and two genes with known functions were identified within fiber strength quantitative trait loci (QTL) regions or near the confidence intervals. We identified 52 key genes potentially related to high fiber strength in a G. mustelinum introgression line and provided significant insights into the study of cotton fiber quality improvement.

The use of MapPop1.0 for choosing a QTL mapping sample from an advanced backcross population

2007 ◽  
Vol 114 (6) ◽  
pp. 1019-1028 ◽  
Author(s):  
C. Birolleau-Touchard ◽  
E. Hanocq ◽  
A. Bouchez ◽  
C. Bauland ◽  
I. Dourlen ◽  
...  
Keyword(s):  
Qtl Mapping ◽  
Backcross Population ◽  
Advanced Backcross ◽  
Advanced Backcross Population

Discovery and Transfer of Genes from Wild Zea Germplasm to Improve Grain Oil and Protein Composition of Temperate Maize

1998 ◽  
Author(s):  
Margaret Smith ◽  
Nurit Katzir ◽  
Susan McCouch ◽  
Yaakov Tadmor
Keyword(s):  
Protein Content ◽  
Oil Content ◽  
Grain Quality ◽  
Yield Potential ◽  
Absolute Difference ◽  
Recurrent Parent ◽  
Agricultural Commodity ◽  
Advanced Backcross ◽  
Maize Varieties ◽  
Project Objectives

Project Objectives 1. Develop and amplify two interspecific populations (annual and perennial teosintes x elite maize inbred) as the basis for genetic analysis of grain quality. 2. Identify quantitative trait loci (QTLs) from teosinte that improve oil, protein, and essential amino acid composition of maize grain. 3. Develop near isogenic lines (NILs) to quantify QTL contributions to grain quality and as a resource for future breeding and gene cloning efforts. 4. Analyze the contribution of these QTLs to hybrid performance in both the US and Israel. 5. Measure the yield potential of improved grain quality hybrids. (NOTE: Yield potential could not be evaluated due to environmentally-caused failure of the breeding nursery where seed was produced for this evaluation.) Background: Maize is a significant agricultural commodity worldwide. As an open pollinated crop, variation within the species is large and, in most cases, sufficient to supply the demand for modem varieties and for new environments. In recent years there is a growing demand for maize varieties with special quality attributes. While domesticated sources of genetic variation for high oil and protein content are limited, useful alleles for these traits may remain in maize's wild relative, teosinte. We utilized advanced backcross (AB) analysis to search for QTLs contributing to oil and protein content from two teosinte accessions: Zea mays ssp. mexicana Race Chalco, an annual teosinte (referred to as Chalco), and Z diploperennis Race San Miguel, a perennial teosinte (referred to as Diplo). Major Conclusions and Achievements Two NILs targeting a Diplo introgression in bin 1.04 showed a significant increase in oil content in homozygous sib-pollinated seed when compared to sibbed seed of their counterpart non-introgressed controls. These BC4S2 NILs, referred to as D-RD29 and D-RD30, carry the Diplo allele in bin 1.04 and the introgression extends partially into bins 1.03 and 1.05. These NILs remain heterozygous in bins 4.01 and 8.02, but otherwise are homozygous for the recurrent parent (RD6502) alleles. NILs were developed also for the Chalco introgression in bin 1.04 but these do not show any improvement in oil content, suggesting that the Chalco alleles differ from the Diplo alleles in this region. Testcross Fl seed and sibbed grain from these Fl plants did not show any effect on oil content from this introgression, suggesting that it would need to be present in both parents of a maize hybrid to have an effect on oil content. Implications, both Scientific and Agricultural The Diplo region identified increases oil content by 12.5% (from 4.8% to 5.4% oil in the seed). Although this absolute difference is not large in agronomic terms, this locus could provide additive increases to oil content in combination with other maize-derived loci for high oil. To our knowledge, this is the first confirmed report of a QTL from teosinte for improved grain oil content in maize. It suggests that further research on grain quality alleles from maize wild relatives would be of both scientific and agricultural interest.

scholarly journals Fine-Mapping of Sorghum Stay-Green QTL on Chromosome10 Revealed Genes Associated with Delayed Senescence

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1026 ◽  
Author(s):  
K. N. S. Usha Kiranmayee ◽  
C. Tom Hash ◽  
S. Sivasubramani ◽  
P. Ramu ◽  
Bhanu Prakash Amindala ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Fine Mapping ◽  
Mapping Population ◽  
Single Gene ◽  
Genotyping By Sequencing ◽  
Introgression Line ◽  
Genomic Region ◽  
Stay Green ◽  
Delayed Senescence ◽  
Genomic Regions

This study was conducted to dissect the genetic basis and to explore the candidate genes underlying one of the important genomic regions on an SBI-10 long arm (L), governing the complex stay-green trait contributing to post-flowering drought-tolerance in sorghum. A fine-mapping population was developed from an introgression line cross—RSG04008-6 (stay-green) × J2614-11 (moderately senescent). The fine-mapping population with 1894 F2 was genotyped with eight SSRs and a set of 152 recombinants was identified, advanced to the F4 generation, field evaluated with three replications over 2 seasons, and genotyped with the GBS approach. A high-resolution linkage map was developed for SBI-10L using 260 genotyping by sequencing—Single Nucleotide Polymorphism (GBS–SNPs). Using the best linear unpredicted means (BLUPs) of the percent green leaf area (%GL) traits and the GBS-based SNPs, we identified seven quantitative trait loci (QTL) clusters and single gene, mostly involved in drought-tolerance, for each QTL cluster, viz., AP2/ERF transcription factor family (Sobic.010G202700), NBS-LRR protein (Sobic.010G205600), ankyrin-repeat protein (Sobic.010G205800), senescence-associated protein (Sobic.010G270300), WD40 (Sobic.010G205900), CPK1 adapter protein (Sobic.010G264400), LEA2 protein (Sobic.010G259200) and an expressed protein (Sobic.010G201100). The target genomic region was thus delimited from 15 Mb to 8 genes co-localized with QTL clusters, and validated using quantitative real-time (qRT)–PCR.

scholarly journals Two SNP Mutations Turned off Seed Shattering in Rice

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 475
Author(s):  
Yu Zhang ◽  
Jiawu Zhou ◽  
Ying Yang ◽  
Walid Hassan Elgamal ◽  
Peng Xu ◽  
...  
Keyword(s):  
Ssr Marker ◽  
Wild Relatives ◽  
Ancestral Haplotype ◽  
Recurrent Parent ◽  
Isogenic Line ◽  
Chromosome 4 ◽  
Cultivated Rice ◽  
Japonica Variety ◽  
Seed Shattering ◽  
Shed Light

Seed shattering is an important agronomic trait in rice domestication. In this study, using a near-isogenic line (NIL-hs1) from Oryza barthii, we found a hybrid seed shattering phenomenon between the NIL-hs1 and its recurrent parent, a japonica variety Yundao 1. The heterozygotes at hybrid shattering 1 (HS1) exhibited the shattering phenotype, whereas the homozygotes from both parents conferred the non-shattering. The causal HS1 gene for hybrid shattering was located in the region between SSR marker RM17604 and RM8220 on chromosome 4. Sequence verification indicated that HS1 was identical to SH4, and HS1 controlled the hybrid shattering due to harboring the ancestral haplotype, the G allele at G237T site and C allele at C760T site from each parent. Comparative analysis at SH4 showed that all the accessions containing ancestral haplotype, including 78 wild relatives of rice and 8 African cultivated rice, had the shattering phenotype, whereas all the accessions with either of the homozygous domestic haplotypes at one of the two sites, including 17 wild relatives of rice, 111 African cultivated rice and 65 Asian cultivated rice, showed the non-shattering phenotype. Dominant complementation of the G allele at G237T site and the C allele at C760T site in HS1 led to a hybrid shattering phenotype. These results help to shed light on the nature of seed shattering in rice during domestication and improve the moderate shattering varieties adapted to mechanized harvest.

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