Genetic distinctness revealed by SSR characterization in Cucumis sativus L. and its wild relatives (original) (raw)
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Diversity in Cucumber Genotypes Based on Morphological Traits and SSR Molecular Markers
Biosciences, Biotechnology Research Asia
ABSTRACT: Biodiversity is one of the most important factors in the survival and improvement of any species. Therefore, germplasm collection is the first step for plant improvement. To investigate their genetic and morphological relationships, 10 morphological traits of 20 genotypes of local cucumbers were evaluated using 9 SSR primers. A high genetic variability was observed for the number of flowers per plant. The values of the Jaccard similarity coefficient ranged between 0.51 and 0.92, indicating a high diversity of the genotypes. To evaluate the genetic similarity among genotypes, a cluster analysis using the UPGMA method was performed based on the Jaccard similarity coefficient. The average genetic distance between genotypes (using the Jaccard similarity coefficient) was 0.74 and the mean polymorphic information content (PIC) was 0.69. The primer SSR13251 had the highest PIC (0.8). The clustering pattern of the SSR markers did not coincide with the groupings based on quantitati...
Genetic diversity assessment of cucumber (Cucumis sativus L.) genotypes using molecular markers
Electronic Journal of Plant Breeding, 2017
In the present investigation, 13 genotypes of cucumber were screened for genetic diversity using eight ISSR primers. The six ISSR primers generated 52 alleles. A total of 52 loci were amplified that exhibited 92.30 per cent polymorphism. A maximum of 11 loci were detected by the primer UBC-855 and UBC-890. Unique bands were also observed by the primers namely UBC-808, UBC-840, and UBC-855. The similarity value ranged from 22 per cent to 80 per cent with the average value of 46 per cent. The genotype Pgyn-1 was found most diverse than others with 33 per cent similarity. The 13 genotypes were grouped into two major groups (A and B) based on ISSR markers. Group A consisted of the most diverse genotype, Pgyn-1. Group B contained the maximum number of genotypes and further divided in two major sub clusters IB and IIB. Sub cluster IB includes small sub cluster of seven genotypes in which Pgyn-4 was found separately whereas, sub cluster IIB contained PCUC-35 and Punjab Naveen as well as shared the cluster genetically while they differ a lot in respect to visual identification.
Genetic diversity of cucumber genotypes revealed by SSR markers and agronomic traits
Genetika, 2019
Understanding the level of genetic diversity and structure of landraces is essential for economical use of genetic resources. In the present study, we investigated the genetic diversity of 36 representative sample of cucumber genotypes based on 10 quantitative traits and 17 polymorphic simple sequence repeat (SSR) markers. Our result revealed variability in flowering behavior, growth habit and fruit characters. We found that the traits, days to opening of first female flower varied from 39.03 to 51.94, fruit length 6.09 to 30.01(cm), fruit weight 104.39 to 277.05(g) and yield per plant 699.38 to 1670.93(g). Genetic distance based on 17 SSR markers among 36 genotypes was quantified ranging from 0.03 to 0.70 indicated a wide diversity among the genotypes selected for evaluation in the present study. These primers produced 2-4 number of alleles with an average 2.76. Polymorphism information content varied from 0.005 to 0.550 with an average of 0.348. The observed heterozygosity mean was 0.098, while gene diversity or expected heterozygosity was 0.625 to 0.057. The distinct genotypes found in this study based on 406
Spanish Journal of Agricultural Research, 2018
The cucumber (Cucumis sativus L.) is an important crop worldwide. In the present study, the molecular genetic diversity of 131 Spanish accessions was analyzed using 23 simple sequence repeat (SSRs). Eighteen of these SSRs were polymorphic; the mean number of alleles, mean observed heterozygosity and mean polymorphic information content were 3.2, 0.065 and 0.229, respectively. Seven SSRs showed a polymorphic information content (PIC) ranging from 0.31 to 0.44, therefore they were reasonably informative. Around 60% of the alleles showed a frequency higher than 0.05, and only one allele in the SSR31399 showed a frequency lower than 0.01. In addition, three accession-specific alleles were found. A high proportion of variation among accessions was obtained. In no case all plants of any accession showed the same genotype and only 18 of 131 Spanish accessions had at least two plants with the same genotype. A cluster analysis did not show any relation with morphological types or geographica...
Plant Systematics and Evolution, 2004
The phylogenetic relationships within the genus Cucumis (a total of 25 accessions belonging to 17 species) were studied using the nuclear ribosomal DNA internal transcribed spacer (ITS) region. The analysis included commercially important species such as melon (C. melo L.) and cucumber (C. sativus). Two additional cucurbit species, watermelon and zucchini, were also included as outgroups. The data obtained reflected the clustering of Cucumis species in four main groups, comprising accessions from cucumber, melon, C. metuliferus and the wild African species. Some of the species clustered in different positions from those reported in classifications previously described by other authors. The data obtained clearly identify a division between the 2n=2x = 14 species (C. sativus) and the 2n = 2x = 24 ones (C. melo and wild species). Within the wild species we identified a subgroup that included C. sagittatus and C. globosus. Oreosyce africana, also classified as Cucumis membranifolius, was shown to be nested within Cucumis. Three accessions previously classified as independent species were shown to be genotypes of Cucumis melo. A set of melon and cucumber SSRs were also used to analyse the Cucumis species and the results were compared with the ITS data. The differential amplification of the SSRs among the accessions made it possible to distinguish three main groups: melon, cucumber and the wild species, though with less detail than applying ITS. Some SSRs were shown to be specific for melon, but other SSRs were useful for producing PCR fragments in all species of the genus.
Genetic diversity in cucumber (cucumis sativus L.): Iii. An evaluation of Indian germplasm
Genetic Resources and Crop Evolution, 1997
Genetic variation in cucumber (Cucumis sativus L. var. sativus) accessions from India was assessed by examining variation at 21 polymorphic isozyme loci. Forty-six accessions acquired by the U.S. National Plant Germplasm System (NPGS) before 1972 were compared with 146 accessions collected during a 1992 U.S.–India expedition to the states of Rajasthan, Madhya Pradesh and Uttar Pradesh, India. Isozymic profiles of these Indian accessions were also compared with 707 previously examined U.S. NPGS cucumber accessions. Two distinct groups (Group 1 and Group 2) were identified within accessions collected in 1992 (0.025 > P > 0.01). Variation at Ak-2, Fdp-2, Gr, Mdh-2, Mpi-1, Per, Pgm and Skdh was important in the detection of this difference. A previously unreported Pgm allele [Pgm (3) – 105] was detected in accessions collected in a market in Pali, Rajasthan. Group 1 contained 37 (27 Madhya Pradesh + 10 Uttar Pradesh) accessions and Group 2 contains 102 (84 Rajasthan + 18 Madhya Pradesh) accessions. Seven accessions (5 Madhya Pradesh + 2 Rajasthan) were not associated with either group. The accessions 20664 (Tonk, Rahjasthan), 20666 (Jaipur, Rahjasthan), 20872 (Sehore, Madhya Pradesh), 20881 (Ashtok, Sehore, Madhya Pradesh) and 21026 (Bhatta, Dehra Dun, Uttar Pradesh) were heterozygous for at least nine loci and represent the genetic diversity within this collection. Isozymic variation in U.S. NPGS accessions acquired before 1972 differed significantly (P > 0.005) from those collected during 1992. All loci were important in the detection of this difference, except Ak-2, Pep-pap, and Pgd-2. When Indian accessions taken collectively (i.e., those acquired before 1972 and during 1992) were compared with an array of 707 C. sativus accessions examined previously, relationships between accessions grouped by country or subcontinent differed from those found in previous work.
The Nucleus, 2011
Interrelationships between the wild and cultivated species of Cucumis L. and their F 1 hybrid was analyzed based on morphological, crossability, chromosome pairing behaviour and seed-protein profiles. Morphologically the wild species, C. pubescens Willd., was found to be distinct from the cultivated taxa C. melo var. melo L. Hybridization studies using the cultivated variety, C. melo and the wild taxa, C. pubescens revealed that the two species of Cucumis were cross compatible. Most of the morphological characters of the F 1 hybrid were intermediate to that of their parents. Fertile hybrid with normal bivalents (n=12) indicated genomic relationships between the wild and cultivated taxa. Seed protein profile revealed that banding pattern of parents and hybrid were closely related, thereby corroborates the close morphological and cytogenetical affinities of the wild and cultivated taxa. The study suggests the possibility to transfer some of the agriculturally important characters of the wild to the popular cultivated varieties through hybridization.
Genome-wide characterization of simple sequence repeats in cucumber (Cucumis sativus L.)
2010
Background: Cucumber, Cucumis sativus L. is an important vegetable crop worldwide. Until very recently, cucumber genetic and genomic resources, especially molecular markers, have been very limited, impeding progress of cucumber breeding efforts. Microsatellites are short tandemly repeated DNA sequences, which are frequently favored as genetic markers due to their high level of polymorphism and codominant inheritance. Data from previously characterized genomes has shown that these repeats vary in frequency, motif sequence, and genomic location across taxa. During the last year, the genomes of two cucumber genotypes were sequenced including the Chinese fresh market type inbred line '9930' and the North American pickling type inbred line 'Gy14'. These sequences provide a powerful tool for developing markers in a large scale. In this study, we surveyed and characterized the distribution and frequency of perfect microsatellites in 203 Mbp assembled Gy14 DNA sequences, representing 55% of its nuclear genome, and in cucumber EST sequences. Similar analyses were performed in genomic and EST data from seven other plant species, and the results were compared with those of cucumber.
Fingerprinting in cucumber and melon (Cucumis spp.) Genotypes using morphological and ISSR markers
Journal of Crop Science and Biotechnology, 2011
In the present investigation, 13 Cucumis genotypes from different geographical areas of India were screened for genetic diversity using 19 morphological traits and 15 ISSR primers. The analysis of morphological traits grouped the accessions into six clusters. Cluster V contained the maximum number of genotypes namely Kanivellari, Long Green, Andaman Local, Perundurai Local, and Sempatti Local. Clusters I and VI contained the minimum number of genotypes. Among all the characters, the highest mean value was observed in fruit length (23.38) and the lowest mean value was observed in stripes on the blossom end (1.31). The 15 ISSR primers generated 109 polymorphic alleles. The average number of ISSR alleles generated was 8.3 per primer and the level of polymorphism was 87.20%. The ISSR primer UBC 825 was highly informative with a PIC value of 0.8934. The 13 genotypes were grouped into six clusters based on ISSR markers. Cluster III contained the maximum number of genotypes, namely Kanivellari, Sankagiri Local, Perundurai Local, Long Melon, and Sempatti Local, while Clusters I, II, IV, and V (Karur Local, Andaman Local, Edapaddi Local, and N 78, respectively) contained the minimum number of genotypes. The ISSR profile generated genotypes specific allele namely, UBC 812700bp and UBC 8121000bp for Cluster VI which contained Cucumis genotypes collected from the northern part of India. Similarly, UBC 808 produced specific allele UBC 808650bp formed in Cluster III which contained genotypes collected from Tamil Nadu and Kerala.