scholarly journals Analysis on genetic diversity of 51 Grape germplasm resources

2019 ◽  
Vol 49 (11) ◽  
Author(s):  
Qingchun Yue ◽  
Chenfei Zhang ◽  
Qinghao Wang ◽  
Wenjing Wang ◽  
Jinyang Wang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Molecular Marker ◽  
Genetic Distance ◽  
Diversity Index ◽  
Gene Diversity ◽  
Breeding Value ◽  
Amplification Efficiency ◽  
Germplasm Resources ◽  
Grape Seeds ◽  
Identification Techniques

ABSTRACT: The objective of this study is to research the genetic diversity of the ‘ Zuijinxiang ’ grape and its mutant breeding F1 plants, we screened the excellent mutant plants with potential breeding value. 50 mutated single plants obtained from 137Cs-γ irradiated ‘Zuijinxiang’ grape seeds were used as research objects, and SCoT molecular marker technology was used for genetic diversity and variation analysis, and clustering research was carried out. The results showed that: (1) 36 SCoT primers produced abundant polymorphisms, and the amplification results showed obvious bright bands, and the amplification efficiency and polymorphism rate were 100%. (2) A total of 221 bands were amplified by 36 primers, of which 175 were rich in polymorphism, the average polymorphic percentage was 80.3%, and the average genetic similarity coefficient was 0.916. (3) The number of observed alleles (Na) ranged from 4 to 8, with an average of 6.1389; the number of effective alleles (Ne) ranged from 1.2772 to 5.6322 with an average of 3.5968; the desired heterozygosity (He) The range is from 0.2192 to 0.8344, the average is 0.6965; the observed heterozygosity (Ho) ranges from 0.1656 to 0.7808 with an average of 0.3035; the Nei’s gene diversity index (H) ranges from 0.2170 to 0.8224 with an average of 0.6863; Shannon-Wiener The index (I) ranges from 0.5186 to 1.8597 with an average of 1.4517. (4) UPGMA clustering of 51 materials showed that the test materials could be divided into three groups when the genetic distance was 0.856. The experiment shows that the genetic diversity of the ‘Zuijinxiang’ radiation variation germplasm resources is rich. In addition, SCoT molecular marker technology can distinguish the materials with close genetic distance, and can be used for early identification techniques of grape mutant materials. This study provides a theoretical basis for the development of excellent mutant germplasm of ‘Zuijinxiang’ grapes.

scholarly journals Genetic diversity and population structure of Meretrix petechialis in China revealed by sequence-related amplified polymorphism markers

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8723 ◽  
Author(s):  
Qiaoyue Xu ◽  
Junhong Zheng ◽  
Hongtao Nie ◽  
Qingzhi Wang ◽  
Xiwu Yan
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Scientific Basis ◽  
Germplasm Resources ◽  
Polymorphic Loci ◽  
Information Index ◽  
Geographical Populations ◽  
Meretrix Petechialis

Genetic variation in nine stocks of Meretrix petechialis collected from China was analyzed using sequence-related amplified polymorphism (SRAP) markers. Eight primer pairs produced 132 polymorphic loci with an average of 16.5 loci per primer pair. A population from Jiangsu had the highest percentage of polymorphic loci at 27.27%, suggesting that these resources had a rich genetic diversity. The Nei’s gene diversity of the nine populations ranged from 0.0647 to 0.0793; a population from Shandong was the lowest and a population from North Korea the highest. The Shannon’s information index was between 0.1023 and 0.1202, with the lowest in the Shandong population and the highest in the Jiangsu population. The Nei’s unbiased genetic distance between the nine populations was 0.0243–0.0570 and the genetic similarity was 0.9446–0.9760; the genetic distance between Guangxi and Shandong populations was the furthest (0.0570) and the genetic distance between Shandong and Jiangsu populations was the closest (0.0243). Nei’s gene diversity analysis indicated that the genetic variance was mainly found within individual geographical populations, and the analysis of molecular variance revealed low but significant genetic differentiation among local and regional populations. The limited gene flow (Nm = 0.555) was inferred as a major reason for the extent of genetic differentiation in M. petechialis. The results obtained here indicated that M. petechialis have high degree of genetic diversity and the potential of further breeding with excellent germplasm resources. This study provides a scientific basis for the protection of germplasm resources and the breeding of M. petechialis.

scholarly journals Assessment of Genetic Diversity of Promising Castor Been (Ricinus communis L.) Genotypes in Nigeria

2019 ◽  
Vol 11 (3) ◽  
pp. 467-474
Author(s):  
Bolaji Zuluqurineen SALIHU ◽  
Olamide Ahmed FALUSI ◽  
Adeyinka Olufemi ADEPOJU ◽  
Ibrahim Wasiu AROLU ◽  
Oladipupo Yusuf DAUDU ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Gene Diversity ◽  
Ricinus Communis ◽  
Polymorphic Information Content ◽  
Block Design ◽  
Genetic Material ◽  
Morphological Data ◽  
Research Attention ◽  
Ricinus Communis L

Castor oil plant (Ricinus communis L.) is an important oil crop with little research attention in Nigeria. In the present research, extent of genetic diversity among 20 Nigerian castor genotypes was determined using morphological descriptors and molecular markers. The genotypes were laid out on a randomized complete block design with three replicated plots. Molecular genotyping of the genotypes was carried out using genomic Simple Sequence Repeats (SSR). The genotypes revealed high divergence in seed colour, seed shape, seed mottle, seed caruncle and seed sizes. Seedling establishment varied from 70.18% (in Acc. 006) to 93.25% (Acc. 001) with average mean of 81.53%. Raceme length ranged from 15.90 cm to 29.54 cm with population mean of 20.80 cm. The highest seed yield (1222.98 kg/ha) was recorded in Acc. 001 and the least (611.46 kg/ha) was observed in Acc. 006. Seed oil content varied between 32.15% in Acc. 042 and 54.03% in Acc. 006. Agglomerative cluster dendrogram constructed from morphological data showed random distribution of the genotypes into three cluster groups irrespective of the sources/collection points. The genetic diversity based on SSR Marker Analysis revealed high average expected heterozygosity (0.74), Polymorphic information content (0.68), Nei’s gene diversity index (0.72) and Shannon's Information index (1.43). The dendrogram constructed from molecular data grouped the twenty genotypes into three groups at coefficient of 0.34. From these findings, it showed that the twenty genotypes evaluated are divergent in nature and they could serve as good genetic material for castor breeding in Nigeria.

scholarly journals ANALISIS KERAGAMAN GENETIK PLASMA NUTFAH KAKAO (Theobroma cacaoL.) BERDASARKANMARKA SSR / Analysis of Genetic Variability Germplasm of Cacao (Theobroma cacaoL.)Basedon SSR Marker

2020 ◽  
Vol 17 (4) ◽  
pp. 156
Author(s):  
Surti Kurniasih ◽  
Rubiyo Rubiyo ◽  
Asep Setiawan ◽  
Agus Purwantara ◽  
Sudarsono Sudarsono
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Ssr Markers ◽  
Theobroma Cacao ◽  
Simple Sequence Repeat ◽  
Ssr Marker ◽  
Gene Diversity ◽  
Sequence Repeat ◽  
Theobroma Cacao L ◽  
Simple Sequence

<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>

scholarly journals Measurement of Genetic Diversity of Chinese Seashore Paspalum Resources through Morphological and Sequence-related Amplified Polymorphism Analysis

2019 ◽  
Vol 144 (6) ◽  
pp. 379-386
Author(s):  
Yan Liu ◽  
Hailin Guo ◽  
Yi Wang ◽  
Jingang Shi ◽  
Dandan Li ◽  
...  
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Cluster Analysis ◽  
Genetic Variation ◽  
Genetic Distance ◽  
Morphological Characteristics ◽  
The United States ◽  
Germplasm Resources ◽  
Seashore Paspalum ◽  
Chinese Germplasm

Seashore paspalum (Paspalum vaginatum) is a notable warm-season turfgrass. Certain germplasm resources are distributed in the southern regions of China. The objectives of this study were to investigate the genetic diversity and genetic variation of Chinese seashore paspalum resources. Morphological characteristics and sequence-related amplified polymorphism (SRAP) markers were used to assess genetic relationships and genetic variation among 36 germplasm resources from China and six cultivars from the United States. The results showed significant variation for 13 morphological characteristics among 42 tested seashore paspalum accessions, and that the phenotypic cv was, in turn, turf height > turf density > internode length > inflorescence density > leaf width > reproductive branch height > spikelet width > leaf length > spikelet number > inflorescence length > internode diameter > inflorescence width > spikelet length. According to the morphological characteristics and cluster analysis, 42 seashore paspalum accessions were divided into six morphological types. In total, 374 clear bands were amplified using 30 SRAP primer combinations; among these bands, 321 were polymorphic with 85.83% polymorphism. SRAP marker cluster analysis showed that 42 seashore paspalum accessions were grouped into seven major groups, with a genetic similarity coefficient ranging from 0.4385 to 0.9893 and genetic distance values ranging from 0.0108 to 0.8244. The high level of genetic diversity occurred among Chinese germplasm, and the genetic distance was relatively high between Chinese germplasm and cultivars introduced from the United States. The patterns in morphological trait variations and genetic diversity will be useful for the further exploitation and use of Chinese seashore paspalum resources.

scholarly journals Analysis of Genetic Diversity and Population Structure of Some Bangladeshi Rice Landraces and HYV

2012 ◽  
Vol 4 (3) ◽  
pp. 757-767 ◽  
Author(s):  
M. M. Hassan ◽  
A. K. M. Shamsuddin ◽  
M. M. Islam ◽  
K. Khatun ◽  
J. Halder
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Allele Number ◽  
Rice Landraces ◽  
Efficient Management ◽  
Ssr Loci ◽  
Pattern Of Variation ◽  
Rice Improvement

Information on the patterns of genetic variation and population structure is essential for rational use and efficient management of germplasms. It helps in monitoring germplasm and can also be used to predict potential genetic gains. Therefore, in the present study genetic diversity of 59 rice genotypes were assessed using 8 simple sequence repeat (SSR) primers. By the DNA profiling, a total of 114 alleles were detected. Allele number per/locus ranged from 9 to 27, with an average of 14.25. Average polymorphism information content (PIC) value was 0.857 with lowest 0.767 to highest 0.857. Mean gene diversity over all SSR loci was 0.870 with a range from 0.792 to 0.948. Fst values for each locus varied from 0.071 to 0.262. Genetic distance between the variety pair ranged from 0.33 to 1.0. The lowest genetic distance was found between Rajashili and Kumragori (2). Cluster and principal coordinate analysis (PCoA) analysis revealed similar pattern of variation. Marker RM11300 was found most polymorphic and robust among the accessions and can be widely used for rice germplasm characterization. The exclusive variability and unique feature of germplasm found in this study can be a gateway for both domestic and global rice improvement.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i3.10416 J. Sci. Res. 4 (3), 757-767 (2012)

scholarly journals Molecular characterization of wheat (Triticum aestivum L.) genotypes through SSR markers

2012 ◽  
Vol 37 (3) ◽  
pp. 389-398 ◽  
Author(s):  
S Islam ◽  
MS Haque ◽  
RM Emon ◽  
MM Islam ◽  
SN Begum
Keyword(s):  
Genetic Diversity ◽  
Triticum Aestivum ◽  
Genetic Distance ◽  
Microsatellite Markers ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Allelic Diversity ◽  
Triticum Aestivum L ◽  
Allele Number ◽  
Average Gene

A study was undertaken to examine the genetic diversity of 12 wheat (Triticum aestivum L.) genotypes, using 4 simple sequence repeats (SSRs). A total of 10 alleles were found. Allele number per locus ranged from 2 to 4 with an average of 2.5. The polymorphic information content (PIC) values ranged from 0.2755 to 0.5411 with an average of 0.3839. The average gene diversity over all SSR loci for the 12 wheat genotypes was 0.4688, ranging from 0.3299 to 0.6042. Cluster analysis based on microsatellite allelic diversity discriminated the varieties into different clusters. Genetic diversity was the highest between variety Gourab and Akbar as well as Gourab and BAW-1064, showing a genetic distance value of 0.4697. The genetic distance was lowest between Balaka and Aghrani as well as Triticale and BAW-1036. Positive correlations were found between gene diversity, number of alleles, the allele size range and the types of repeat motif of microsatellite markers. It was found from this study that microsatellite markers could characterize and discriminate all of the genotypes. More primers should be used for saturation of different regions in further studies. Bangladesh J. Agril. Res. 37(3): 389-398, September 2012 DOI: http://dx.doi.org/10.3329/bjar.v37i3.12082

Genetic Variation in Invasive Populations of Yellow Toadflax (Linaria vulgaris) in the Western United States

Weed Science ◽  
2008 ◽  
Vol 56 (3) ◽  
pp. 394-399 ◽  
Author(s):  
Sarah M. Ward ◽  
Scott D. Reid ◽  
Judy Harrington ◽  
Jason Sutton ◽  
K George Beck
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Recombination ◽  
Diversity Index ◽  
Gene Diversity ◽  
Group Method ◽  
Restricted Gene Flow ◽  
Genetic Structuring ◽  
Invasive Weed ◽  
Yellow Toadflax

Intraspecific genetic variation may contribute significantly to invasiveness and control problems, but has been characterized to date in relatively few invasive weed species. We examined 56 intersimple sequence repeat (ISSR) loci in 220 individuals from 11 invading populations of yellow toadflax sampled across five western states. All populations showed high levels of genetic diversity. Estimated values for Shannon's diversity measure ranged from 0.217 to 0.388, and for expected heterozygosity from 0.178 to 0.260. Nei's total gene diversity index (HT), on the basis of all individuals across all populations, was 0.267. Partitioning of genetic variance using analysis of molecular variance revealed 1.7% of genetic variation among regional population groups, 29.1% among populations within groups, and 69.2% within populations, consistent with expectations for an outcrossing species but suggesting little geographic differentiation. Pairs of adjacent individuals identical at all ISSR loci that appeared to be ramets of a single clone were detected in only one population. This indicates that patch expansion in yellow toadflax is driven more by sexual reproduction via seed than by rhizomatous clonal spread, at least at the spatial scale of sampling for this study. Eight populations had significant values for Mantel's R at P = 0.05, suggesting some fine-scale positive genetic structuring, possibly from restricted gene flow. Population clustering on the basis of Nei's genetic distance between populations and unweighted pair group method with arithmetic mean did not reflect geographic location. It is likely that multiple introductions of this species have occurred across the Intermountain West, followed by extensive genetic recombination. High levels of genetic diversity within yellow toadflax populations pose management challenges, as already seen in reports of variable response to herbicide application and limited impacts of biocontrol agent releases.

scholarly journals GENETIC DIVERSITY OF UPLAND RICE LANDRACES FROM JAVA ISLAND AS REVEALED BY SSR MARKERS

2015 ◽  
Vol 16 (1) ◽  
pp. 1
Author(s):  
Sutoro Sutoro ◽  
Puji Lestari ◽  
Hakim Kurniawan
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Ssr Markers ◽  
Upland Rice ◽  
Diversity Index ◽  
Crop Improvement ◽  
Conservation Strategy ◽  
Genetic Diversity Index ◽  
Rice Landraces ◽  
Glutinous Rice

Java Island is one of origins of a large number of indigenous upland rice accessions, which may serve as valuable plant genetic resources for future crop improvement in Indonesia. However, these landraces especially non-glutinous and glutinous rice are rapidly being lost because of land-use, agricultural practices and other factors. A better understanding of genetic diversity of local upland rice is important for crop improvement program, crop management and conservation strategy. This study aimed to evaluate the genetic diversity of upland rice landraces originating from Java Island. A total of 82 upland rice accessions comprising of 55 non-glutinous rice and 27 glutinous type were genotyped using the 16 simple sequence repeat (SSR) markers. The result showed that a total of 74 alleles were found with major allele frequency found on RM431 (0.96). Most of the SSR markers (56.3%) showed high discriminating power as represented by polymorphic informa-tion content (PIC) value higher than 0.5. A moderate genetic diversity index was detected in all landraces, which was 0.55. Genetic diversity index of non-glutinous and glutinous rice were 0.54 and 0.53, respectively. Their genetic distance was about 0.057. The phylogenetic tree generated two main clusters that demonstrated discrimination among landraces according to the individual genetic properties rather than their geographical origins and grain types (non-glutinous and glutinous type). The levels of genetic diversity were varied across rice types and geographical origins. According to the regions, the closest genetic distance was found between upland rice landraces from Central Java and West Java (0.040). The information derived from this study is important, in combination with phenotypic data, to identify desired useful traits came from different origins of the gene pool to be used for breeding purposes.

scholarly journals Genetic Relationship Among Ten Promising Eggplant Varieties Using RAPD Markers

1970 ◽  
Vol 19 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Md. Sanaullah Biswas ◽  
Md. Abdullah Yousuf Akhond ◽  
Md. Al-Amin ◽  
Mahmuda Khatun ◽  
Muhammed Rezwan Kabir
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Genetic Relationship ◽  
Plant Tissue ◽  
Rapd Markers ◽  
Gene Diversity ◽  
Similarity Index ◽  
The Other ◽  
Upgma Dendrogram ◽  
Potential Tool

RAPD technique was used as a tool for assessing genetic diversity and varietal relationships among ten varieties of eggplant. Out of 21 primers screened four were selected. With these primers 76 clear and bright fragments were obtained of which 44 fragments considered polymorphic. The proportion of polymorphic loci and gene diversity values across all loci were 57.89% and 0.23, respectively. The UPGMA dendrogram based on genetic distance segregated the ten varieties of eggplant into two main clusters. Dohazari, Kazla, Nayantara and ISD-006 were grouped together in cluster I whereas Uttara, Islampuri, Khatkhatia, Singnath, BARI Begun-08 and Eggplant Line-083 into cluster II. Kazla and Nayantara variety pair was very close to each other with the highest intervarietal similarity index (92.54%) and lowest genetic distance (0.14). On the other hand, Khatkhatia and Nayantara pair was the lowest intervarietal similarity index (41.67%) with highest genetic distance (0.48). Therefore, identification of genetically distinct varieties using RAPD markers could be a potential tool for eggplant improvement. Key words: Eggplant, Polymorphism, Genetic relationship, RAPD D.O.I. 10.3329/ptcb.v19i2.5006 Plant Tissue Cult. & Biotech. 19(2): 119-126, 2009 (December)

scholarly journals Phenotypic and Genotypic Diversity for Drought Tolerance among and within Perennial Ryegrass Accessions

HortScience ◽  
2015 ◽  
Vol 50 (8) ◽  
pp. 1148-1154 ◽  
Author(s):  
Yu Cui ◽  
Jinsheng Wang ◽  
Xingchun Wang ◽  
Yiwei Jiang
Keyword(s):  
Genetic Diversity ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Genetic Distance ◽  
Perennial Ryegrass ◽  
Molecular Mechanisms ◽  
Phenotypic Diversity ◽  
Gene Diversity ◽  
Leaf Water Content ◽  
Drought Response

Perennial ryegrass (Lolium perenne L.) is a popular cool-season forage and turfgrass in temperate regions. Due to its self-incompatible and out-crossing nature, perennial ryegrass may show a high degree of heterozygosity. Perennial ryegrass generally is susceptible to drought stress, but variations of drought response of individual genotypes within a particular accession or cultivar are not well understood. The objective of this study was to characterize phenotypic diversity of drought tolerance within and among accessions in relation to genetic diversity in perennial ryegrass. Five individual genotypes from each of six accessions varying in origin and growth habits were subjected to drought stress in a greenhouse. Leaf wilting, plant height, chlorophyll fluorescence (Fv/Fm) and leaf water content (LWC) differed significantly among accessions as well as among genotypes within each accession under well-watered control and drought stress conditions. Fv/Fm was highly correlated with LWC under drought stress. Genetic diversity among and within accessions were identified by using previously characterized 23 simple sequence repeat markers. Across accessions, the mean major allele frequency, gene diversity, and heterozygosity values were 0.66, 0.43, and 0.66, respectively. Accessions with closer genetic distance generally had similar drought responses, while accessions with greater genetic distance showed distinct drought tolerance. Significant differences in drought tolerance among and within accessions, especially for individual genotypes within one accession, indicated that variations of drought response could be used for enhancing breeding programs and studying molecular mechanisms of stress tolerance in perennial ryegrass.

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