Identification of a Major Quantitative Trait Locus Conditioning Resistance to Greenbug Biotype E in Sorghum PI 550610 Using Simple Sequence Repeat Markers

2007 ◽  
Vol 100 (5) ◽  
pp. 1672-1678 ◽  
Author(s):  
Y. Q. Wu ◽  
Y. Huang ◽  
D. R. Porter ◽  
C. G. Tauer ◽  
L. Hollaway
Keyword(s):  
Quantitative Trait Locus ◽  
Quantitative Trait ◽  
Simple Sequence Repeat ◽  
Major Quantitative Trait Locus ◽  
Sequence Repeat ◽  
Simple Sequence Repeat Markers ◽  
Trait Locus ◽  
Simple Sequence

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 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.

scholarly journals Quantitative Trait Locus Analysis in Squash (Cucurbita moschata) Based on Simple Sequence Repeat Markers and Restriction Site-Associated DNA Sequencing Analysis

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 71
Author(s):  
Takuma Hashimoto ◽  
Nakao Kubo ◽  
Kanako Nishimura ◽  
Atsushi J. Nagano ◽  
Azusa Sasaki ◽  
...  
Keyword(s):  
Quantitative Trait ◽  
Simple Sequence Repeat ◽  
Restriction Site ◽  
Sequencing Analysis ◽  
Cucurbita Moschata ◽  
Sequence Repeat ◽  
Fruit Traits ◽  
F2 Population ◽  
Trait Locus ◽  
Simple Sequence

Squash (Cucurbita moschata) displays wide morphological and genetic variations; however, limited information is available regarding the genetic loci of squash that control its agronomic traits. To obtain basic genetic information for C. moschata, an F2 population was prepared derived from a cross between the Vietnamese cultivar ‘Bí Hồ Lô TN 6 (TN 6)’ and the Japanese cultivar ‘Shishigatani’, and flowering and fruit traits were examined. Overall, the traits showed a continuous distribution in the F2 population, suggesting that they were quantitative traits. A linkage map was constructed based on simple sequence repeat and restriction site-associated DNA (RAD) markers to detect quantitative trait loci (QTLs). Twelve QTLs for flowering and fruit traits, as well as one phenotypic trait locus, were successfully localized on the map. The present QTLs explained the phenotypic variations at a moderate to relatively high level (16.0%–47.3%). RAD markers linked to the QTLs were converted to codominant cleaved amplified polymorphic sequence (CAPS) and derived CAPS markers for the easy detection of alleles. The information reported here provides useful information for understanding the genetics of Cucurbita and other cucurbit species, and for the selection of individuals with ideal traits during the breeding of Cucurbita vegetables.

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