scholarly journals A new intervarietal linkage map and its application for quantitative trait locus analysis of "gigas" features in bread wheat

Genome ◽  
2005 ◽  
Vol 48 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Kazuhiro Suenaga ◽  
Mireille Khairallah ◽  
H M William ◽  
David A Hoisington
Keyword(s):  
Quantitative Trait Locus ◽  
Linkage Map ◽  
Qtl Analysis ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Linkage Groups ◽  
Spike Number ◽  
Trait Locus ◽  
Dh Lines ◽  
Simple Sequence

A doubled-haploid (DH) population from an intervarietal cross between the Japanese cultivar 'Fukuho-komugi' and the Israeli wheat line 'Oligoculm' was produced by means of wheat × maize crosses. One hundred seven DH lines were genotyped to construct a simple sequence repeat (SSR) based linkage map with RFLP, RAPD, and inter-simple sequence repeat markers. Out of 570 loci genotyped, 330 were chosen based on their positions on the linkage map to create a "framework" map for quantitative trait locus (QTL) analysis. Among the 28 linkage groups identified, 25 were assigned to the 21 chromosomes of wheat. The total map length was 3948 cM, including the three unassigned linkage groups (88 cM), and the mean interval between loci was 12.0 cM. Loci with segregation distortion were clustered on chromosomes 1A, 4B, 4D, 5A, 6A, 6B, and 6D. After vernalization, the DH lines were evaluated for spike number per plant (SN) and spike length (SL) in a greenhouse under 24-h daylength to assess the "gigas" features (extremely large spikes and leaves) of 'Oligoculm'. The DH lines were also autumn-sown in the field in two seasons (1990–1991 and 1997–1998) for SN and SL evaluation. QTL analysis was performed by composite interval mapping (CIM) with the framework map to detect QTLs for SN and SL. A major QTL on 1AS, which was stable in both greenhouse and field conditions, was found to control SN. This QTL was close to the glume pubescence locus (Hg) and explained up to 62.9% of the total phenotypic variation. The 'Oligoculm' allele restricted spike number. The SSR locus Xpsp2999 was the closest locus to this QTL and is considered to be a possible marker for restricted tillering derived from 'Oligoculm'. Eight QTLs were detected for SL. The largest QTL detected on 2DS was common to the greenhouse and field environments. It explained up to 33.3% of the total phenotypic variation. The second largest QTL on 1AS was common to the greenhouse and the 1997–1998 season. The position of this QTL was close to that for the SN detected on 1AS. The association between SN and SL is discussed.Key words: linkage map, microsatellite, QTL, spike length, spike number.

Implementing molecular marker technology in forage improvement

2003 ◽  
pp. 229-238
Author(s):  
M. Faville ◽  
B. Barrett ◽  
A. Griffiths ◽  
M. Schreiber ◽  
C. Mercer ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Genetic Variation ◽  
White Clover ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Linkage Groups ◽  
Seedling Vigour ◽  
Genome Map ◽  
Trait Locus ◽  
Simple Sequence

Accelerated improvement of two cornerstones of New Zealand's pastoral industries, per ennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), may be realised through the application of markerassisted selection (MAS) strategies to enhance traditional plant breeding programmes. Genome maps constructed using molecular markers represent the enabling technology for such strategies and we have assembled maps for each species using EST-SSR markers - simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs) representing genes. A comprehensive map of the white clover genome has been completed, with 464 EST-SSR and genomic SSR marker loci spanning 1125 cM in total, distributed across 16 linkage groups. These have been further classified into eight pairs of linkage groups, representing contributions from the diploid progenitors of this tetraploid species. In perennial ryegrass a genome map based exclusively on EST-SSR loci was constructed, with 130 loci currently mapped to seven linkage groups and covering a distance of 391 cM. This map continues to be expanded with the addition of ESTSSR loci, and markers are being concurrently transferred to other populations segregating for economically significant traits. We have initiated gene discovery through quantitative trait locus (QTL) analysis in both species, and the efficacy of the white clover map for this purpose was demonstrated with the initial identification of multiple QTL controlling seed yield and seedling vigour. One QTL on linkage group D2 accounts for 25.9% of the genetic variation for seed yield, and a putative QTL accounting for 12.7% of the genetic variation for seedling vigour was detected on linkage group E1. The application of MAS to forage breeding based on recurrent selection is discussed. Keywords: genome map, marker-assisted selection, perennial ryegrass, QTL, quantitative trait locus, SSR, simple sequence repeat, white clover

scholarly journals An Extended Linkage Map for Watermelon Based on SRAP, AFLP, SSR, ISSR, and RAPD Markers

2006 ◽  
Vol 131 (3) ◽  
pp. 393-402 ◽  
Author(s):  
A. Levi ◽  
C.E. Thomas ◽  
T. Trebitsh ◽  
A. Salman ◽  
J. King ◽  
...  
Keyword(s):  
Linkage Map ◽  
Simple Sequence Repeat ◽  
Citrullus Lanatus ◽  
Average Distance ◽  
Acc Synthase ◽  
Segregation Ratio ◽  
Issr Markers ◽  
Sequence Repeat ◽  
Linkage Groups ◽  
Simple Sequence

Seventy-one amplified fragment length polymorphism (AFLP), 93 sequence related amplified polymorphism (SRAP), and 14 simple sequence repeat (SSR) markers were used to extend an initial genetic linkage map for watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]. The initial map was based on 151 randomly amplified polymorphic DNA (RAPD) and 30 and inter-simple sequence repeat (ISSR) markers. A testcross population previously used for mapping of RAPD and ISSR markers was used in this study: {plant accession Griffin 14113 [C. lanatus var. citroide (L.H. Bailey) Mansf.] × the watermelon cultivar New Hampshire Midget (C. lanatus var. lanatus)} × PI 386015 [C. colocynthis (L.) Schrad.]. The linkage map contains 360 DNA markers distributed on 19 linkage groups, and covers a genetic distance of 1976 cM with an average distance of 5.8 cM between two markers. A genomic DNA clone representing 1-amino-cyclopropane-1-carboxylic acid (ACC-) synthase gene, involved in ethylene biosynthesis, was also mapped. As in previous mapping studies for watermelon, a large number of AFLP and SRAP markers were skewed away from the 1:1 segregation ratio, and had to be excluded from the final mapping analysis. The stringent mapping criteria (JoinMap 3.0 mapping program) produced linkage groups with marker order consistent with those reported in previous mapping study for watermelon.

A framework linkage map of perennial ryegrass based on SSR markers

Genome ◽  
2006 ◽  
Vol 49 (4) ◽  
pp. 354-364 ◽  
Author(s):  
G P Gill ◽  
P L Wilcox ◽  
D J Whittaker ◽  
R A Winz ◽  
P Bickerstaff ◽  
...  
Keyword(s):  
Linkage Map ◽  
Ssr Markers ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Simple Sequence Repeat ◽  
Ssr Marker ◽  
Sequence Repeat ◽  
Linkage Groups ◽  
Marker Loci ◽  
Simple Sequence

A moderate-density linkage map for Lolium perenne L. has been constructed based on 376 simple sequence repeat (SSR) markers. Approximately one third (124) of the SSR markers were developed from GeneThresher® libraries that preferentially select genomic DNA clones from the gene-rich unmethylated portion of the genome. The remaining SSR marker loci were generated from either SSR-enriched genomic libraries (247) or ESTs (5). Forty-five percent of the GeneThresher SSRs were associated with an expressed gene. Unlike EST-derived SSR markers, GeneThresher SSRs were often associated with genes expressed at a low level, such as transcription factors. The map constructed here fulfills 2 definitions of a "framework map". Firstly, it is composed of codominant markers to ensure map transferability either within or among species. Secondly, it was constructed to achieve a level of statistical confidence in the support-for-order of marker loci. The map consists of 81 framework SSR markers spread over 7 linkage groups, the same as the haploid chromosome number. Most of the remaining 295 SSR markers have been placed into their most likely interval on the framework map. Nine RFLP markers and 1 SSR marker from another map constructed using the same pedigree were also incorporated to extend genome coverage at the terminal ends of 5 linkage groups. The final map provides a robust framework with which to conduct investigations into the genetic architecture of trait variation in this commercially important grass species.Key words: Framework map, perennial ryegrass, SSR, simple sequence repeat, GeneThresher, Lolium perenne.

Development of simple sequence repeat markers and construction of a high-density linkage map of Capsicum annuum

2013 ◽  
Vol 31 (4) ◽  
pp. 909-920 ◽  
Author(s):  
Toru Sugita ◽  
Yukari Semi ◽  
Hiromasa Sawada ◽  
Yumi Utoyama ◽  
Yuko Hosomi ◽  
...  
Keyword(s):  
Linkage Map ◽  
Capsicum Annuum ◽  
Simple Sequence Repeat ◽  
High Density ◽  
Sequence Repeat ◽  
Simple Sequence Repeat Markers ◽  
High Density Linkage Map ◽  
Simple Sequence

Genetic mapping of ascochyta blight resistance in chickpea (Cicer arietinum L.) using a simple sequence repeat linkage map

Genome ◽  
2007 ◽  
Vol 50 (1) ◽  
pp. 26-34 ◽  
Author(s):  
B. Tar’an ◽  
T.D. Warkentin ◽  
A. Tullu ◽  
A. Vandenberg
Keyword(s):  
Linkage Map ◽  
Cicer Arietinum ◽  
Phenotypic Variation ◽  
Simple Sequence Repeat ◽  
Ascochyta Blight ◽  
Ascochyta Rabiei ◽  
Blight Resistance ◽  
Sequence Repeat ◽  
Cicer Arietinum L ◽  
Simple Sequence

Ascochyta blight, caused by the fungus Ascochyta rabiei (Pass.) Lab., is one of the most devastating diseases of chickpea ( Cicer arietinum L.) worldwide. Research was conducted to map genetic factors for resistance to ascochyta blight using a linkage map constructed with 144 simple sequence repeat markers and 1 morphological marker (fc, flower colour). Stem cutting was used to vegetatively propagate 186 F2 plants derived from a cross between Cicer arietinum L. ‘ICCV96029’ and ‘CDC Frontier’. A total of 556 cutting-derived plants were evaluated for their reaction to ascochyta blight under controlled conditions. Disease reaction of the F1 and F2 plants demonstrated that the resistance was dominantly inherited. A Fain’s test based on the means and variances of the ascochyta blight reaction of the F3 families showed that a few genes were segregating in the population. Composite interval mapping identified 3 genomic regions that were associated with the reaction to ascochyta blight. One quantitative trait locus (QTL) on each of LG3, LG4, and LG6 accounted for 13%, 29%, and 12%, respectively, of the total estimated phenotypic variation for the reaction to ascochyta blight. Together, these loci controlled 56% of the total estimated phenotypic variation. The QTL on LG4 and LG6 were in common with the previously reported QTL for ascochyta blight resistance, whereas the QTL on LG3 was unique to the current population.

scholarly journals Quantitative Trait Locus Analysis in Avocado: The Challenge of a Slow-maturing Horticultural Tree Crop

2019 ◽  
Vol 144 (5) ◽  
pp. 352-362
Author(s):  
Vanessa E.T.M. Ashworth ◽  
Haofeng Chen ◽  
Carlos L. Calderón-Vázquez ◽  
Mary Lu Arpaia ◽  
David N. Kuhn ◽  
...  
Keyword(s):  
Quantitative Trait Locus ◽  
Linkage Group ◽  
Linkage Map ◽  
Qtl Analysis ◽  
Quantitative Trait ◽  
Persea Americana ◽  
Phenotypic Traits ◽  
Experimental Population ◽  
Tree Crop ◽  
Trait Locus

The glossy, green-fleshed fruit of the avocado (Persea americana) has been the object of human selection for thousands of years. Recent interest in healthy nutrition has singled out the avocado as an excellent source of several phytonutrients. Yet as a sizeable, slow-maturing tree crop, it has been largely neglected by genetic studies, owing to a long breeding cycle and costly field trials. We use a small, replicated experimental population of 50 progeny, grown at two locations in two successive years, to explore the feasibility of developing a dense genetic linkage map and to implement quantitative trait locus (QTL) analysis for seven phenotypic traits. Additionally, we test the utility of candidate-gene single-nucleotide polymorphisms developed to genes from biosynthetic pathways of phytonutrients beneficial to human health. The resulting linkage map consisted of 1346 markers (1044.7 cM) distributed across 12 linkage groups. Numerous markers on Linkage Group 10 were associated with a QTL for flowering type. One marker on Linkage Group 1 tracked a QTL for β-sitosterol content of the fruit. A region on Linkage Group 3 tracked vitamin E (α-tocopherol) content of the fruit, and several markers were stable across both locations and study years. We argue that the pursuit of linkage mapping and QTL analysis is worthwhile, even when population size is small.

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