Identification and validation of functional markers in a global rice collection by association mapping

Genome ◽  
2014 ◽  
Vol 57 (6) ◽  
pp. 355-362 ◽  
Author(s):  
Mojtaba Jahani ◽  
Ghorbanali Nematzadeh ◽  
Behnaz Dolatabadi ◽  
Sayyed Hamidreza Hashemi ◽  
Ghasem Mohammadi-Nejad

Recent results indicate that marker-assisted selection is an effective approach to reduce the cost and to improve the efficacy and accuracy of selection in plant breeding. This study was conducted to identify and validate molecular markers linked to important breeding traits by association mapping. The association was evaluated between 81 molecular markers (STS, SSR, Indel, CAPS, and PCR-based SNP) and 15 morphological traits in a global panel of 100 rice (Oryza sativa) accessions. The population structure analysis identified three main subpopulations. Obvious kinship relationships were also detected between the rice accessions. Association analysis was performed based on the mixed linear model by considering population structure and family relatedness. In addition, the false discovery rate method was used to correct the multiple testing. A total of 47 marker–trait associations were identified, including 22 markers for 14 traits. Among all, the polymorphism at the loci DDR-GL was highly associated with grain characters (grain length, grain width, and length/width ratio). In addition, marker RM3148 was responsible for five important traits simultaneously. Results demonstrated that such informative markers can be very useful for rice breeding programs using marker-assisted selection. Moreover, the diverse populations of rice accessions are a valuable resource for association mapping of morphological traits.

Genome ◽  
2007 ◽  
Vol 50 (10) ◽  
pp. 963-973 ◽  
Author(s):  
Jianjun Zhao ◽  
Maria-João Paulo ◽  
Diaan Jamar ◽  
Ping Lou ◽  
Fred van Eeuwijk ◽  
...  

Association mapping was used to investigate the genetic basis of variation within Brassica rapa , which is an important vegetable and oil crop. We analyzed the variation of phytate and phosphate levels in seeds and leaves and additional developmental and morphological traits in a set of diverse B. rapa accessions and tested association of these traits with AFLP markers. The analysis of population structure revealed four subgroups in the population. Trait values differed between these subgroups, thus defining associations between population structure and trait values, even for traits such as phytate and phosphate levels. Marker–trait associations were investigated both with and without taking population structure into account. One hundred and seventy markers were found to be associated with the observed traits without correction for population structure. Association analysis with correction for population structure led to the identification of 27 markers, 6 of which had known map positions; 3 of these were confirmed in additional QTL mapping studies.


2021 ◽  
Author(s):  
Rahul Kumar ◽  
Anilabh Das Munshi ◽  
Tusar Kanti Behera ◽  
GOGRAJ SINGH JAT ◽  
Harshwardhan Choudhary ◽  
...  

Abstract In several regions of the world, low productivity in this crop is attributed to several factors including poor understanding of the genomic complexity of important traits associated with fruit quality and yield. Therefore, genome wide association analysis was performed for important traits using simple sequence repeats (SSR) markers. Significant variation was recorded for all the studied traits in 78 cucumber genotypes under two environments (open field and net house) which indicated that the constituted association panel was suitable for association mapping. Genotyping was done using 60 highly polymorphic SSRs. By performing genome scanning out of 60 SSR markers, using mixed linear model (MLM) approach 4 and 6 markers explained an average of 23.93% and 17.37 % of the trait variation under net house and open field condition, respectively. Based on MLM approach two markers on 3rd chromosome (UW084942) and 4th chromosome (UW062953) found to be associated with the average fruit weight (g) under both net house and open field condition. Population structure analysis revealed four distinct sub-populations that corroborated with the geographical origin as well as fruit quality and quantitative traits. The four sub-populations (A–D) had fixation index percentage (Fst) equal to 24.35 29.48, 37.17 and 8.97 respectively, supporting the existence of moderate population structures. Therefore, the extensive phenotypic and genotypic characterization, population structure, and markers associated with critical traits provided in this study will facilitate marker assisted improvement programs in cucumber.


2020 ◽  
Vol 51 (6) ◽  
pp. 611-619
Author(s):  
Adrian Medina-Montes ◽  
Darwin Hernández-Herrera ◽  
Javier Beltrán-Herrera ◽  
Donicer Montes-Vergara

The objective of this study was to evaluate the genetic diversity of the Colombian Creole donkey in the Department of Sucre using Random Amplified Microsatellites (RAM) molecular markers. In 100 individuals from the five subregions of the department, DNA was extracted and five RAM primers were amplified by PCR. In all, 291 bands were found, on average 11.96±1.45 per primer, the highest value in CCA (18±2.23) and the lowest in TG and GT (8.8±0.44). CA was the most polymorphic primer (88.09±10.91%) with the highest heterozygosity value (He) (0.376±0.021), while the lowest was GT (0.341±0.076 and 0.101±0.040, respectively). Intrapopulation analysis showed an average of 66.50±1.72 bands, of which 89.86±24.04% were polymorphic. The highest number of bands (63±3.84) was found in the Gulf of Morrosquillo (GO) subpopulation, and the lowest in Mojana (MO) (48±2.88); however, the highest value of polymorphic loci (81.16%) and He (0.335±0.022) were found in the Montes de María (MM) subpopulation, making it the most diverse. The average genetic diversity for the entire population was 0.351±0.021 bands. The population structure analysis showed a 10% variation between subpopulations, with an FST value of 0.17±0.01 (P<0.05). Genetic distances between subpopulations showed that MO and GO were the most distant. The RAM markers are effective in assessing the genetic diversity of the Creole donkey, which has high values of genetic diversity, particularly the MM subpopulation. The genetic revealed structure could be the result of natural geographical barriers between the subregions.


2015 ◽  
Vol 61 (4) ◽  
pp. 129-138 ◽  
Author(s):  
Katarína Ražná ◽  
Janka Nôžková ◽  
Lucia Hlavačková ◽  
Nina Brutch ◽  
Elizaveta Porokhovinova ◽  
...  

Abstract MicroRNAs (miRNAs) are a class of non-coding RNAs about 20-24 nucleotides long. They play an important role in the gene regulation at the post-transcriptional level. They affect the plant genome response to environmental stress. The miRNA-based molecular markers is type of functional markers reported in very few plants. However, the information connected to the evaluation of genotypes by this type of markers within a single species is missing. Considering the stability, polymorphism, functionality and transferability potential of miRNA-based markers, the research was conducted to apply selected types of them (miR156b, miR408a and the combined type of miR156b/miR408a) for the genotyping analysis of eight flax genotypes of different origin together with the morphology analyses. A total of 145 miRNA loci were identified, of which 19 were unique. The highest numbers of miRNA loci (57) and unique fragments (9) as well as the highest percentage of polymorphism and the extent of polymerase chain reaction (PCR) amplification of miRNA fragments have been observed with the combination of miR156b-F and miR408-F markers. By means of the miRNA markers has been recorded the unique profile of the miRNA loci for individual accessions. The morphology study has shown that the genotypes are the same in the expression of selected morphological traits despite the different use and different places of origin. However, we have identified an interface between some of morphological traits and miRNA-based markers for genotyping the genetic resources of flax. By mutually linking these two types of markers, we were able to determine unique genotypes of flax.


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