scholarly journals Use of simple sequence repeat (SSR) markers for screening blue disease resistance in cotton germplasm exchange

2015 ◽  
Vol 14 (41) ◽  
pp. 2871-2875 ◽  
Author(s):  
Faustine Christopher ◽  
Vieira Hoffmann Lucia ◽  
Ismail Tibazarwa Flora ◽  
Lukonge Everina
2020 ◽  
pp. 1032-1041
Author(s):  
Wassu Mohammed ◽  
Beyene Amelework ◽  
Hussein Shimelis

The study was carried out to assess the genetic diversity and population structure of okra collections from diverse geographic origin using selected polymorphic simple sequence repeat (SSR) markers. Thirty-two okra accessions collected from three geographic regions were genotyped using 16 selected SSR markers. The SSR markers generated a total of 71 loci of which 67% were polymorphic. Genetic distances among accessions ranged from 2.2 to 7.1, with a mean of 4.65. Gene diversity ranged from 0.10 to 0.78 with a mean of 0.52. Genetic clustering classified the accessions into three major clusters and four sub-clusters. Each cluster and sub-cluster consisted of accessions derived from different sources. Analysis of molecular variance revealed that 67%, 81% and 83% of the total genetic variation detected was found within populations of geographic origin, altitude and collection district, respectively. The observed moderate to high population differentiation could partly be attributed to limited germplasm exchange, agro-ecological differences, and partly by selection pressure. The present study revealed the presence of high genetic diversity and population divergence among okra collections from Ethiopia. The study demonstrated that a collection strategy for conservation of okra genetic resources should focus on sampling of representative genotypes covering wide geographic regions and altitudinal ranges of target agro-ecologies.


2004 ◽  
Vol 129 (2) ◽  
pp. 204-210 ◽  
Author(s):  
Riaz Ahmad ◽  
Dan Potter ◽  
Stephen M. Southwick

Simple sequence repeat (SSR) and sequence related amplified polymorphism (SRAP) molecular markers were evaluated for detecting intraspecific variation in 38 commercially important peach and nectarine (Prunus persica) cultivars. Out of the 20 SSR primer pairs 17 were previously developed in sweet cherry and three in peach. The number of putative alleles revealed by SSR primer pairs ranged from one to five showing a low level of genetic variability among these cultivars. The average number of alleles per locus was 2.2. About 76% of cherry primers produced amplification products in peach and nectarine, showing a congeneric relationship within Prunus species. Only nine cultivars out of the 38 cultivars could be uniquely identified by the SSR markers. For SRAP, the number of fragments produced was highly variable, ranging from 10 to 33 with an average of 21.8 per primer combination. Ten primer combinations resulted in 49 polymorphic fragments in this closely related set of peaches and nectarines. Thirty out of the 38 peach and nectarine cultivars were identified by unique SRAP fingerprints. UPGMA Cluster analysis based on the SSR and SRAP polymorphic fragments was performed; the relationships inferred are discussed with reference to the pomological characteristics and pedigree of these cultivars. The results indicated that SSR and SRAP markers can be used to distinguish the genetically very close peach and nectarine cultivars as a complement to traditional pomological studies. However, for fingerprinting, SRAP markers appear to be much more effective, quicker and less expensive to develop than are SSR markers.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 471
Author(s):  
Jae-Ryoung Park ◽  
Won-Tae Yang ◽  
Yong-Sham Kwon ◽  
Hyeon-Nam Kim ◽  
Kyung-Min Kim ◽  
...  

The assessment of the genetic diversity within germplasm collections can be accomplished using simple sequence repeat (SSR) markers and association mapping techniques. The present study was conducted to evaluate the genetic diversity of a colored rice germplasm collection containing 376 black-purple rice samples and 172 red pericarp samples, conserved by Dong-A University. There were 600 pairs of SSR primers screened against 11 rice varieties. Sixteen informative primer pairs were selected, having high polymorphism information content (PIC) values, which were then used to assess the genetic diversity within the collection. A total of 409 polymorphic amplified fragments were obtained using the 16 SSR markers. The number of alleles per locus ranged from 11 to 47, with an average of 25.6. The average PIC value was 0.913, ranging from 0.855 to 0.964. Four hundred and nine SSR loci were used to calculate Jaccard’s distance coefficients, using the unweighted pair-group method with arithmetic mean cluster analysis. These accessions were separated into several distinctive groups corresponding to their morphology. The results provided valuable information for the colored rice breeding program and showed the importance of protecting germplasm resources and the molecular markers that can be derived from them.


2016 ◽  
Vol 106 (4) ◽  
pp. 362-371 ◽  
Author(s):  
P. Cheng ◽  
X. M. Chen ◽  
D. R. See

Puccinia striiformis causes stripe rust on cereal crops and many grass species. However, it is not clear whether the stripe rust populations on grasses are able to infect cereal crops and how closely they are related to each other. In this study, 103 isolates collected from wheat, barley, triticale, rye, and grasses in the United States were characterized by virulence tests and simple sequence repeat (SSR) markers. Of 69 pathotypes identified, 41 were virulent on some differentials of wheat only, 10 were virulent on some differentials of barley only, and 18 were virulent on some differentials of both wheat and barley. These pathotypes were clustered into three groups: group one containing isolates from wheat, triticale, rye, and grasses; group two isolates were from barley and grasses; and group three isolates were from grasses and wheat. SSR markers identified 44 multilocus genotypes (MLGs) and clustered them into three major molecular groups (MG) with MLGs in MG3 further classified into three subgroups. Isolates from cereal crops were present in one or more of the major or subgroups, but not all, whereas grass isolates were present in all of the major and subgroups. The results indicate that grasses harbor more diverse isolates of P. striiformis than the cereals.


2020 ◽  
Vol 17 (4) ◽  
pp. 156
Author(s):  
Surti Kurniasih ◽  
Rubiyo Rubiyo ◽  
Asep Setiawan ◽  
Agus Purwantara ◽  
Sudarsono Sudarsono

<p>Microsatellite or simple sequence repeat (SSR) markers have proven to be an excellent tool for cultivar identification, pedigree analysis, and genetic distance evaluations among organisms. The objectives of this research were to characterize cacao collection of Indonesian Coffee and Cacao Research Institute (ICCRI) and to analyze their genetic diversity using SSR markers. In this research, 39 SSR primer pairs were used to amplify genomic DNA of 29 cacao clones. Amplified SSR fragments for each primer pair were scored as individual band and used to determine genetic distance among evaluated cacao clones. Results of the experiment indicated that all SSR primer pairs evaluated were able to produce SSR markers for 29 cacao clones. The results also indicated that 34 out of 39 microsatellite loci evaluated were polymorphic, while 5 others were monomorphic. The total number of observed alleles among 29 clones was 132. Number of alleles per locus ranged from 4-8, with an average of 5.5 alelles per locus. Results of data analysis indicated that the PIC value was 0.665, the observed heterozigosity (Ho) was 0.651, and the gene diversity (He) was 0.720. The PIC, Ho, and He values were considered high. Genetic distances were evaluated using NTSys version 2.1 and dendrogram was constructed. Results of analysis indicated that 12 cacao clones evaluated were clustered in the first group with diversity coefficient of &lt; 3.75. Nine cacao clones were in the second group but with the same value of diversity coefficient (&lt;7.50). The rest of the cacao clones were in the third group with diversity coefficient of&gt;7.50. Based on those finding, all SSR primer pairs evaluated could be used to analyze cacao genome and be useful for genetic diversity analysis of cacao germplasm. The SSR marker analysis in ICCRI cacao collections resulted in high PIC, high observed heterozygosity, and high genetic diversity.</p><p>Key words: Theobroma cacao L, microsatelite, molecular marker, genetic diversity, heterozygosity</p><p> </p><p><strong>Abstrak</strong></p><p>Marka mikrosatelit atau sekuens sederhana berulang (simple sequence repeat = SSR) terbukti merupakan alat yang bagus untuk identifikasi kultivar, analisis pedigree, dan evaluasi jarak genetik berbagai organisme. Penelitian ini bertujuan untuk:1) karakterisasi kakao koleksi Pusat penelitian Kopi dan Kakao Indonesia menggunakan marka SSR dan 2) analisis keragaman genetik klon-klon kakao koleksi dengan menggunakan marka SSR. Dalam penelitian ini, 39 pasangan primer SSR telah digunakan untuk amplifikasi DNA genomik dari 29 klon kakao. Skoring pita SSR hasil amplifikasi menggunakan masing-masing pasangan primer dilakukan secara terpisah dan digunakan untuk menentukan jarak genetik di antara klon kakao yang dievaluasi. Hasil percobaan menunjukkan bahwa semua pasangan primer SSR yang digunakan mampu menghasilkan pita DNA hasil amplifikasi (marka SSR) untuk 29 klon kakao yang diuji. Hasil penelitian juga menunjukkan bahwa 34 dari 39 lokus SSR yang dianalisis bersifat polimorfik sedangkan lima primer yang lain bersifat monomorfik. Dari 29 klon kakao yang dievaluasi, telah berhasil diamplifikasi sebanyak 132 alel, dengan kisaran antara 4-8 alel/lokus. Rataan jumlah alel per lokus sebanyak 5,50. Hasil analisis data yang dilakukan juga menunjukkan nilai PIC untuk marka SSR yang digunakan sebesar 0,665. Untuk populasi klon kakao yang dievaluasi, diperoleh nilai rataan heterosigositas pengamatan (Ho) sebesar 0,651 dan rataan diversitas gen (He) sebesar 0,720. Nilai PIC Ho dan He yang didapat tergolong tinggi. Berdasarkan analisis keragaman dengan menggunakan program NTSys, diperoleh hasil 12 klon kakao berada dalam grup pertama (koefisien keragaman&lt;3,75) dan9 klon berada dalam grup kedua, dengan koefisien keragaman &lt; 7,50. Sedangkan klon-klon lainnya mempunyai koefisien keragaman &gt; 7,50. Berdasarkan hasil penelitian dan analisis data disimpulkan bahwa marka SSR dapat digunakan untuk menganalisis keragaman genetik plasma nutfah kakao. Tingkat polimorfisme yang dihasilkan marka SSR relatif tinggi. Tingkat heterosigositas plasma nutfah kakao koleksi Puslit Kopi dan Kakao Indonesiarelatif tinggi, dan keragaman genetiknyacukup tinggi.</p><p>Kata kunci : Theobroma cacao L, mikrosatelit, marka molekuler, keragaman genetik, heterosigositas</p>


2016 ◽  
Vol 11 (2) ◽  
pp. 163-172
Author(s):  
ALOK KUMAR SINGH ◽  
N.K. SINGH ◽  
V.K. SINGH ◽  
D.P. SINGH ◽  
N.P. SINGH

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