scholarly journals GENETIC DIVERSITY OF S3 MAIZE GENOTYPES RESISTANT TO DOWNY MILDEW BASED ON SSR MARKERS

2016 ◽  
Vol 16 (2) ◽  
pp. 79
Author(s):  
Amran Muis ◽  
Nurnina Nonci ◽  
Marcia B. Pabendon

The compulsory requirement for releasing new high yielding maize varieties is resistance to downy mildew. The study aimed to determine the level of homozygosity, genetic diversity, and  genetic distance of 30 S3 genotypes of maize. Number of primers to be used were 30 polymorphic SSR loci which are distributed over the entire maize genomes. The S3 genotypes used were resistant to downy mildew with homozygosity level of >80%, genetic distance between the test and tester strains >0.7, and anthesis silking interval (ASI) between inbred lines and tester lines was maximum 3 days. The results showed that 30 SSR primers used were spread evenly across the maize genomes which were manifested in the representation of SSR loci on each chromosome of a total of 10 chromosomes. The levels of polymorphism ranged from 0.13 to 0.78, an average of 0.51, and the number of alleles ranged from 2 to 8 alleles per SSR locus, an average of 4 alleles per SSR locus. The size of nucleotides in each locus also varied from 70 to 553 bp. Cophenetic correlation value (r) at 0.67 indicated that the Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA) was less reliable for differentiating genotypes in five groups. Of the total of 30 genotypes analyzed, 17 genotypes had homozygosity level of >80% so it can be included in the hybrid assembly program.

2016 ◽  
Vol 16 (2) ◽  
pp. 79 ◽  
Author(s):  
Amran Muis ◽  
Nurnina Nonci ◽  
Marcia B. Pabendon

The compulsory requirement for releasing new high yielding maize varieties is resistance to downy mildew. The study aimed to determine the level of homozygosity, genetic diversity, and  genetic distance of 30 S3 genotypes of maize. Number of primers to be used were 30 polymorphic SSR loci which are distributed over the entire maize genomes. The S3 genotypes used were resistant to downy mildew with homozygosity level of >80%, genetic distance between the test and tester strains >0.7, and anthesis silking interval (ASI) between inbred lines and tester lines was maximum 3 days. The results showed that 30 SSR primers used were spread evenly across the maize genomes which were manifested in the representation of SSR loci on each chromosome of a total of 10 chromosomes. The levels of polymorphism ranged from 0.13 to 0.78, an average of 0.51, and the number of alleles ranged from 2 to 8 alleles per SSR locus, an average of 4 alleles per SSR locus. The size of nucleotides in each locus also varied from 70 to 553 bp. Cophenetic correlation value (r) at 0.67 indicated that the Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA) was less reliable for differentiating genotypes in five groups. Of the total of 30 genotypes analyzed, 17 genotypes had homozygosity level of >80% so it can be included in the hybrid assembly program.


2007 ◽  
Vol 132 (3) ◽  
pp. 357-367 ◽  
Author(s):  
P. Escribano ◽  
M.A. Viruel ◽  
J.I. Hormaza

Cherimoya (Annona cherimola Mill.) is an underused fruit crop with a clear niche for expansion in subtropical climates. In this study, 16 simple sequence repeat (SSR) loci were used to find molecular polymorphisms among 279 cherimoya accessions from a worldwide ex situ field germplasm collection. A total of 79 amplification fragments were amplified with 16 pairs of SSR primers, with an average of 4.9 bands/SSR. Mean expected and observed heterozygosities averaged 0.53 and 0.44, respectively. The total value for the probability of identity was 4.34 × 10−8. The SSRs studied resulted in 267 different fingerprinting profiles, of which 258 were unique genotypes; the rest were putative cases of synonymies or mislabeling errors. Unweighted pair group method with arithmetic averages (UPGMA) cluster analysis indicated the relationships among the analyzed accessions, showing some specific groups related to their geographical origins. Analysis of molecular variance (AMOVA) was performed to examine the distribution of genetic variation of the 148 accessions collected from putative cherimoya origin areas in Ecuador and Peru, showing that the major variations occurred within valleys in each country. The results confirmed the usefulness of microsatellites for identification of genetic diversity and geographic origin of cherimoya and are discussed in terms of their implications for ex situ conservation of cherimoya genetic resources.


1970 ◽  
Vol 38 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Saaimatul Huq ◽  
Md Shahidul Islam ◽  
Abu Ashraqur Sajib ◽  
Nadim Ashraf ◽  
Samiul Haque ◽  
...  

Characterization of sixteen jute genotypes, from Corchorus olitorius L. and Corchorus capsularis L. using jute specific SSR marker attained a high polymorphism value of 92.20%. A total of 171 different alleles were amplified by 27 primer pairs with a mean of 6.33 ± 2.04 alleles per locus. The genetic diversity was also relatively high (0.81 ± 0.06). The Un-weighted Pair-group Method with Arithmetic averages (UPGMA) cluster analysis of the 16 jute genotypes produced a dendogram, which was in concordance with known information. The study reinforces the utility of SSR primers for providing useful and high levels of markers for individual plant genotypes even with a narrow genetic base. Key words: Jute; Genetic diversity; SSR; Genotypes; Polymorphism DOI: 10.3329/bjb.v38i2.5140 Bangladesh J. Bot. 38(2): 153-161, 2009 (December)  


1970 ◽  
Vol 34 (3) ◽  
pp. 493-503 ◽  
Author(s):  
KK Ghosh ◽  
ME Haque ◽  
S Parvin ◽  
F Akhter ◽  
MM Rahim

This investigation was aimed at exploring the genetic diversity and relationship among nine Brassica varieties, namely BARI Sharisha-12, Agrani, Sampad, BINA Sharisha-4, BINA Sharisha-5, BARI Sharisha-13, Daulot, Rai-5, Alboglabra using Random Amplified Polymorphic DNA (RAPD) markers. In total, 59 reproducible DNA bands were generated by four arbitrary selected primers of which 58 (98.03%) bands were proved to be polymorphic. These bands ranged from 212 to 30686 bp in size. The highest proportion of polymorphic loci and gene diversity values were 37.29% and 0.1373, respectively, for BARI Sharisha-12 and the lowest proportion of polymorphic loci and gene diversity values were 8.47% and 0.0318, 8.47% and 0.0382 for BINA Sharisha-4 and Rai-5, respectively. A dendrogram was constructed using unweighted pair group method of arithmetic mean (UPGMA). The result of cluster analysis indicated that the 9 accessions were capable of being classified into 2 major groups. One group consists of BARI Sharisha-12, Agrani, Sampad, Daulot, Rai-5, Alboglabra. where Daulot and Rai-5 showed the lowest genetic distance of 0.049. And another group contains BINA Sharisha-4, BINA Sharisha-5, and BARI Sharisha-1 3, where BINA Sharisha-5 and BARI sharisha-13 showed genetic distance of 0.071. Key Words: RAPD, Brassica, genetic distance, polymorphic band. DOI: 10.3329/bjar.v34i3.3976 Bangladesh J. Agril. Res. 34(3) : 493-5032, September 2009


Horticulturae ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 143
Author(s):  
Lei Zhu ◽  
Huayu Zhu ◽  
Yanman Li ◽  
Yong Wang ◽  
Xiangbin Wu ◽  
...  

Simple sequence repeats (SSRs) are widely used in mapping constructions and comparative and genetic diversity analyses. Here, 103,056 SSR loci were found in Cucurbita species by in silico PCR. In general, the frequency of these SSRs decreased with the increase in the motif length, and di-nucleotide motifs were the most common type. For the same repeat types, the SSR frequency decreased sharply with the increase in the repeat number. The majority of the SSR loci were suitable for marker development (84.75% in Cucurbita moschata, 94.53% in Cucurbita maxima, and 95.09% in Cucurbita pepo). Using these markers, the cross-species transferable SSR markers between C. pepo and other Cucurbitaceae species were developed, and the complicated mosaic relationships among them were analyzed. Especially, the main syntenic relationships between C. pepo and C. moschata or C. maxima indicated that the chromosomes in the Cucurbita genomes were highly conserved during evolution. Furthermore, 66 core SSR markers were selected to measure the genetic diversity in 61 C. pepo germplasms, and they were divided into two groups by structure and unweighted pair group method with arithmetic analysis. These results will promote the utilization of SSRs in basic and applied research of Cucurbita species.


2019 ◽  
Vol 6 (2) ◽  
pp. 215-225
Author(s):  
Nazmul Islam Mazumder ◽  
Tania Sultana ◽  
Prtitish Chandra Paul ◽  
Dinesh Chandra Roy ◽  
Deboprio Roy Sushmoy ◽  
...  

Twenty six rice lines of PBRC (salt tolerant line-20) × BRRI dhan-29 were used to evaluate salinity tolerance at the seedling stage and tested for salt tolerance using RAPD markers. Salinity screening was done using hydrophonic system at the greenhouse following IRRI standard protocol. Among the studied line, ten were moderately salinity tolerant, nine susceptible and rest of the lines highly susceptible. For assessing genetic diversity and relationship of F3 rice lines including two parents were tested against PCR-based Random Amplified Polymorphic DNA (RAPD) technique using three arbitrary decamer primers; OPA02, OPC01, and OPC12. Selected three primers generated a total of 14 bands. Out of 14 bands, 12 bands (86.67%) were polymorphic and 2 bands (13.33%) were monomorphic. The Unweighted Pair Group Method of Arithmetic Means (UPGMA) dendrogram constructed from Nei’s (1972) genetic distance produced 2 main clusters of the 28 rice genotypes. Most of the moderately tolerant lines and PBRC (STL-20) (tolerant variety) were grouped in same cluster due to lower genetic distance, while maximum susceptible along with BRRI dhan29 (susceptible variety) showed higher genetic distance with PBRC (STL-20) and moderately tolerant lines. This result indicates that the lines which formed grouped together, they are less diversed. On the other hand the lines remain in different clusters or different groups, are much diversed. Thus RAPD perform a potentially simple, rapid and reliable method to evaluate genetic diversity and molecular characterization as well. Res. Agric., Livest. Fish.6(2): 215-225, August 2019


2016 ◽  
Vol 154 (7) ◽  
pp. 1254-1269 ◽  
Author(s):  
A. SINGH ◽  
H. K. DIKSHIT ◽  
D. SINGH ◽  
N. JAIN ◽  
M. ASKI ◽  
...  

SUMMARYExpressed sequence tag-simple sequence repeat (EST-SSR) markers were used to analyse genetic diversity among three Lens species. The SSR loci amplified successfully in wild species, with 94·82% transferability in Lens culinaris subsp. orientalis, 95·4% in Lens nigricans, 98·81% in L. culinaris subsp. odemensis, 94·82% in L. culinaris subsp. tomentosus and 96·55% in Lens ervoides. Ninety-nine alleles (average 3·41 alleles/locus) were detected by 29 SSR markers. Based on the unweighted pair group method with arithmetic mean cluster analysis, all the genotypes were grouped into three clusters at a similarity level of 0·30. The diversity analysis indicated no species-specific clustering of the wild and cultivated species. Wild species L. nigricans and L. culinaris subsp. odemensis, L. culinaris subsp. orientalis and L. ervoides were grouped in Cluster I, whereas the Mediterranean land races of L. culinaris subsp. culinaris and L. culinaris subsp. tomentosus formed a separate group in Cluster II A. Cluster II B comprised L. ervoides, L. culinaris subsp. orientalis and L. culinaris subsp. culinaris. Clusters II C, II D and II F included cultivated Indian lentil genotypes. Cluster II E comprised Indian and Mediterranean germplasm lines. Cluster II F included three early maturing germplasm lines, whereas Cluster III included only two germplasm lines. The functional annotation of SSR-containing unigenes revealed that a majority of genes were involved in an important transport-related function or were a component of metabolic pathways. A high level of polymorphism of EST-SSRs and their transferability to related wild species indicated that these markers could be used for molecular screening, map construction, comparative genomic studies and marker-assisted selection.


2021 ◽  
Vol 19 (1) ◽  
pp. 1-13
Author(s):  
MI Haque ◽  
S Ishtiaque ◽  
MM Islam ◽  
TA Mujahidi ◽  
MA Rahim

The molecular characterization of chilli germplasm was done based on estimation of genetic diversity among the germplasm by using SSR markers. Forty chilli germplasms were analyzed using eight SSR primers. The SSR primers produced 30 SSR loci with an average value of 3.75 alleles per SSR locus. The similarity index matrix ranged from zero to 2.74. Polymorphic information content (PIC) of the SSR primers ranged from 0.543 to 0.735 with an average value of 0.658. The highest number (five) of allele was observed in primer CAMS-647, whereas the primers CAMS-864, CAMS-880 and CAMS-885 showed lowest number (three) of allele. The smallest allele was found in case of primer CAMS- 236 (176 bp), while the longest allele was detected for the primer CAMS- 864 (288 bp). Based on similarity matrix using the un-weighed Pair Group Method of Arithmetic Means (UPGMA) dendrogram, chilli germplasms were grouped into four main clusters. SSR markers showed genetic variability in the studied chilli germplasm.  SAARC J. Agric., 19(1): 1-13 (2021)


2015 ◽  
Vol 14 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Ndenum S. Shitta ◽  
Michael T. Abberton ◽  
Adenubi I. Adesoye ◽  
Daniel B. Adewale ◽  
Olaniyi Oyatomi

African yam bean, AYB (Sphenostylis stenocarpa Hochst. ex. A. Rich Harms), is a tuberous legume of tropical Africa. AYB has the potential to significantly boost food security due to its considerable nutritional qualities. However, the crop is underutilized. To efficiently utilize AYB genetic resources for its improvement, it is necessary to understand the crop's diversity. This study investigated the amplification ability of 36 cowpea simple sequence repeat (SSR) primers across AYB genomic DNA, extracted from 67 accessions. Thirteen (36%) of the cowpea SSRs showed transferability in AYB. Eight of these SSRs amplified above 60% of AYB accessions and generated 55 polymorphic fragments with an average of 6.9 per primer. Polymorphic information content ranged from 0.6691 to 0.8857 with an average of 0.7791. This study also assessed the genetic diversity within 67 AYB accessions using eight cowpea (Vigna unguiculata L. Walp)-derived SSR primers. The result revealed a high level of genetic diversity with simple matching coefficient ranging from 0.458 to 1.000. A dendrogram depicting three main clusters was generated based on unweighted pair group method with arithmetic average. Cluster 1 was the most diverse with a dissimilarity range of 0.517–1.000. The level of genetic diversity revealed in this study indicates that the studied AYB germplasm can be exploited for genetic improvement. Additionally, the transferable markers will aid AYB genome research and also make possible the comparative mapping between AYB and cowpea.


2020 ◽  
pp. 1-10
Author(s):  
Shaoyu Chen ◽  
Tao Wu ◽  
Liangjun Xiao ◽  
Delu Ning ◽  
Li Pan

Abstract Iron walnut, Juglans sigillata Dode, restricted to southwestern China, has its centre of distribution in Yunnan Province which has a varied climate, geography and rich plant diversity. Yunnan contains abundant J. sigillata germplasm. In this study, a provincial-scale set of walnut germplasm resources (14 populations comprising 1122 individuals) was evaluated for genetic diversity based on 20 simple sequence repeat (SSR) loci. The number of SSR alleles per locus ranged from 7 to 27, with an average of 17.55. Mean allelic richness and mean private allelic richness ranged from 3.40 to 4.62 and 0.11 to 0.36, with average of 3.93 and 0.30, respectively. Expected heterozygosity (He) varied from 0.26 to 0.78, with an average of 0.57. Polymorphism information content ranged from 0.22 to 0.79, with an average of 0.57. Genetic differentiation (FST) was 0.05, indicating that only 5% of total genetic variability was inter-populational, a finding supported by an analysis of molecular variance and STRUCTURE analysis. Relatively high gene flow (Nm = 6.70) was observed between populations. A unweighted pair-group method with arithmetic analysis classified the 14 populations into two major groups. Mantel testing uncovered a significant correlation between geographic distance and genetic distance (r = 0.33, P = 0.04). Overall, the research revealed a moderately high level of genetic diversity in the germplasm and low genetic differentiation among populations, which showed great potential for further development and exploitation of this resource.


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