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Guan X.,China Agricultural University | Guan X.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | Hirata M.,Forage Crop Research Institute | Ding C.,Jiangsu Academy of Agricultural Sciences | And 11 more authors.
Grassland Science | Year: 2014

Simple sequence repeat (SSR) markers and conserved-intron scanning primer (CISP) markers developed from cereal expressed sequence tag sequences were successfully used to construct a linkage map for Lolium multiflorum Lam. using a L. multiflorum × Lolium temulentum L. × L. temulentum BC1 population consisting of 88 individuals. The genetic linkage map included 108 SSR and 84 CISP markers that covered 488.8 centimorgan (cM) in seven linkage groups, ranging in length from 42.2 to 98.9 cM. The average density of markers was 2.5 cM. Syntenic relationships between Lolium and rice (Oryza sativa L.) based on the positions of the CISP markers largely agree with the previously reported relationships. The map constructed in the present study will be useful in developing a denser linkage map as well as for analysis of quantitative trait loci for important agronomic traits in Lolium species. Copyright. © 2014 Japanese Society of Grassland Science.

Li P.,China Agricultural University | Li P.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | Guo Y.,China Agricultural University | Guo Y.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | And 13 more authors.
Tropical Plant Biology | Year: 2016

Seed dormancy is a key domestication trait for major crops, which is acquired in long-term systems development processes and enables the survival of plants in adverse natural conditions. It is a complex trait under polygenic control and is affected by endogenous and environmental factors. In the present study, a major seed dormancy QTL in sorghum (Sorghum bicolor (L.) Moench), qDor7, detected previously, was fine mapped using a large, multi-generational population. The qDor7 locus was delimited to a 96-kb region which contains 16 predicted gene models. These results lay a solid foundation for cloning qDor7. In addition, the functional markers tightly linked to the seed dormancy QTL may be used in marker-assisted selection for seed dormancy in sorghum. © 2016, Springer Science+Business Media New York.

Han L.,China Agricultural University | Han L.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | Chen J.,China Agricultural University | Chen J.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | And 9 more authors.
Theoretical and Applied Genetics | Year: 2015

Key message: We detected seven QTLs for 100-grain weight in sorghum using an F2population, and delimitedqGW1to a 101-kb region on the short arm of chromosome 1, which contained 13 putative genes. Abstract: Sorghum is one of the most important cereal crops. Breeding high-yielding sorghum varieties will have a profound impact on global food security. Grain weight is an important component of grain yield. It is a quantitative trait controlled by multiple quantitative trait loci (QTLs); however, the genetic basis of grain weight in sorghum is not well understood. In the present study, using an F2 population derived from a cross between the grain sorghum variety SA2313 (Sorghum bicolor) and the Sudan-grass variety Hiro-1 (S. bicolor), we detected seven QTLs for 100-grain weight. One of them, qGW1, was detected consistently over 2 years and contributed between 20 and 40 % of the phenotypic variation across multiple genetic backgrounds. Using extreme recombinants from a fine-mapping F3 population, we delimited qGW1 to a 101-kb region on the short arm of chromosome 1, containing 13 predicted gene models, one of which was found to be under purifying selection during domestication. However, none of the grain size candidate genes shared sequence similarity with previously cloned grain weight-related genes from rice. This study will facilitate isolation of the gene underlying qGW1 and advance our understanding of the regulatory mechanisms of grain weight. SSR markers linked to the qGW1 locus can be used for improving sorghum grain yield through marker-assisted selection. © 2015, Springer-Verlag Berlin Heidelberg.

Guo Y.,China Agricultural University | Guo Y.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | Li P.,China Agricultural University | Li P.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | And 14 more authors.
Tropical Plant Biology | Year: 2015

Seed dormancy is an important trait during the domestication of major crops. Dormant seeds are unable to germinate under conditions normally suitable for non-dormant seeds. Quantitative trait loci (QTLs) and genes affecting seed dormancy in sorghum remain largely unknown. To identify the genomic regions controlling seed dormancy in sorghum, we produced two F2 segregating populations from two crosses between a deep dormant weedy line B140 (as the female parent) and two weak dormant grain lines CK60B and MS138B (as the male parents). A genetic linkage map of the B140/CK60B population was constructed with 216 simple sequence repeat (SSR) markers spanning 1710.3 cM. One QTL on chromosome 4 and two QTLs on chromosome 7 were identified in the B140/CK60B population. They accounted for 17.9 to 24.9% of the phenotypic variance using a simple interval mapping method. The QTL on chromosome 4 was verified in another F2 mapping population (MS138B/B140). To understand the mechanism of dormancy, we conducted an expression analysis of four sorghum genes encoding homologs of dormancy genes of other plant species: Vp1 (maize), DOG1 (Arabidopsis), qSD12 and Sdr4 (rice). We demonstrated that there were clear differences in the expression level of all these four genes between the two parental lines with different seed dormancy level, and their expression were also tissue-specific with the expression levels of qSD12 low throughout all growth stages and tissues in B140. Our findings will help to define the genetic mechanism of seed dormancy in sorghum, and the identified QTLs may be useful biomarker for selection in sorghum improvement programs. © 2015, Springer Science+Business Media New York.

Wang Y.,China Agricultural University | Wang Y.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | Tan L.,China Agricultural University | Tan L.,Beijing Key Laboratory of Crop Genetic Improvement and Genome | And 10 more authors.
PLoS ONE | Year: 2015

Time to maturity is a critical trait in sorghum (Sorghum bicolor) breeding, as it determines whether a variety can be grown in a particular cropping system or ecosystem. Understanding the nucleotide variation and the mechanisms of molecular evolution of the maturity genes would be helpful for breeding programs. In this study, we analyzed the nucleotide diversity of Ma3, an important maturity gene in sorghum, using 252 cultivated and wild sorghum materials from all over the world. The nucleotide variation and diversity were analyzed based both on race- and usage-based groups. We also sequenced 12 genes around the Ma3 gene in 185 of these materials to search for a selective sweep and found that purifying selection was the strongest force on Ma3, as low nucleotide diversity and low-frequency amino acid variants were observed. However, a very special mutation, described as ma3R, seemed to be under positive selection, as indicated by dramatically reduced nucleotide variation not only at the loci but also in the surrounding regions among individuals carrying the mutations. In addition, in an association study using the Ma3 nucleotide variations, we detected 3 significant SNPs for the heading date at a high-latitude environment (Beijing) and 17 at a low-latitude environment (Hainan). The results of this study increases our understanding of the evolutionary mechanisms of the maturity genes in sorghum and will be useful in sorghum breeding. © 2015 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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