Genetic Structure in Tunisian Apricot, Prunus armeniaca L., Populations Propagated by Grafting: A Signature of Bottleneck Effects and Ancient Propagation by Seedlings

In order to give insights into the origin and historical selection process of Tunisian apricot propagated by grafting, 31 cultivars from three areas presenting contrasting ecological conditions – Kairouan, Testour and Ras Jbel were compared to cultivars from Europe, North America, North Africa, Turkey, Iran and China, using 234 AFLP markers. The phenetic analysis allowed to distinguish 5 clusters, the four previously defined groups: – ‘diversification’, ‘geographically adaptable’, ‘continental European’ and ‘Mediterranean’ – groups and the Tunisian one. The partitioning of genetic diversity within and between cultivar groups assessed according to the Bayesian approach and assuming Hardy–Weinberg equilibrium, showed a loss of 21.81–38.49% of genetic diversity in Tunisian apricot compared to Mediterranean and diversification groups, respectively. Genetic variation occurred within Tunisian subgroups rather than among (F_ST = 0.060) evidencing a narrow genetic pool. Mediterranean and Tunisian groups were the least differentiated. Comparing them, 24 AFLP fragments discriminated the Mediterranean group from the Tunisian group but most of them where also shared by the other groups. Strongly differentiated gene pool and low genetic diversity are probably the result of bottleneck effects linked to the occurrence of propagation by seedlings rather than by grafting during the introduction periods in the North and the Centre of Tunisia. This study points at the propagation by seedlings as an important factor which should be taken into account to understand the evolution of apricot in South Mediterranean areas.     

Genetic Relationship between <Emphasis Type="Italic">Castanea sativa</Emphasis> Mill. Trees from North-western to South Spain Based on Morphological Traits and Isoenzymes

This study is focused in the main chestnut growing areas from north- to south-western Spain. We studied 50 accessions corresponding to 22 cultivars named by local growers; 11 from Andalucía, 9 from Castilla-León, and 2 from Extremadura. These were compared with 22 types classified previously in Galicia (82 accessions). Ten morphological traits and five isoenzyme systems were used to classify them and establish genetic relationships. A lower genetic variability has been found in Extremadura (middle Spain) and Andalucía (south) than in Galicia (north western) which may be because of the lower importance of the crop in those areas and the geographic barriers between them. Galicia could be the origin of the types found in Castilla-León, Extremadura, and south-western Andalucía, and the types found in Central Andalucía were closer to those found in Castilla-León and Extremadura. Most accessions studied (117/132) could be classified positively, making 37 out of 44 cultivars found from northern to southern Spain. Three groups of synonymies were found in Castilla-León: ‘Brava’ and ‘Negral’, ‘Gallego’ and ‘Injerto’, and ‘Rapega’ and ‘Verdello’. Most of the Spanish types have been propagated as a principal clone. Variability within the types is important and must be considered to select the best clones as cultivars.     

Ploidic and Molecular Analysis of ‘Morado de Huetor’ Asparagus (Asparagus officinale L.) Population; A Spanish Tetraploid Landrace

A study has been conducted into the genetic variation analysis of the tetraploid asparagus landrace ‘Morado de Huetor’ and its relationship with current commercial cultivars using Random Amplified Polymorphic DNA (RAPD) molecular markers. The presence of different ploidic levels in the ‘Morado de Huetor’ landrace has been also studied using cytogenetic analysis. Ten decamer oligonucleotides were used to obtain RAPD markers and to characterise 52 individuals of ‘Morado de Huetor’, 7 of the tetraploid cultivar ‘Purple Passion’, and 55 of 5 diploid hybrid commercial cultivars. Jaccard similarity index was calculated and a cluster analysis using UPGMA (Unweighted Pair-Group Method using Arithmetic Average) was performed. Tetraploid asparagus, ‘Morado de Huetor’ and ‘Purple Passion’, were well differentiated from the diploid ones showing a higher genetic variability. This result suggests a different origin for tetraploid and diploid asparagus varieties. Within the diploid cultivars a variety distribution was obtained. A specific monomorphic band (OPB20₈₈₃) was found in tetraploid varieties. Within the diploid cultivars, two bands (OPB20₈₃₀, OPC15₇₀₅) can be used to distinguish between the hybrid cultivars used in this study. Tri-, penta-, hexa-, and octoploid plants were found in ‘Morado de Huetor’. The origin of these ploidic levels is discussed and their use in the development of new varieties is proposed. In conclusion, ‘Morado de Huetor’ is a genetic resource that could be used to increase the narrow genetic background reported in diploid asparagus cultivars.     

Genetic diversity of cultivated and wild Ussurian Pear (<Emphasis Type="Italic">Pyrus ussuriensis</Emphasis> Maxim.) in China evaluated with M13-tailed SSR markers

Eight genomic SSR markers with a M13 tail attached were used to assess the genetic diversity of 72 Ussurian Pear accessions (Pyrus ussuriensis Maxim.) in China. The M13-tailed method was effective in discriminating all the 32 wild accessions. All the 40 Ussurian Pear cultivars could be successfully discriminated with the exception of 4 sets of synonymies or spots. A total of 108 alleles were obtained with an average of 13.5 per locus. The expected heterozygosity, observed heterozygosity, and power of discrimination were 0.78, 0.63, and 0.86 respectively. Three triploid cultivars (‘Anli’, ‘Ruan’er’, and ‘Pitaiguo’), and one wild accession, P. ussuriensis ‘Xilin-3’, showed three alleles at some SSRs. The number of alleles and observed heterozygosity per locus for 40 Ussurian Pear cultivars were 9.1 and 0.62, respectively, lower than the values of 32 wild accessions which were 11.3 and 0.65, respectively. A dendrogram based on the SSR genotypes was obtained, showing two major groups corresponding to cultivated group and wild group. All the cultivars fell into the cultivated group. Some subgroups (Nanguoli subgroup, Zhibazi subgroup, Xiangshuili subgroup, Balixiang subgroup, Anli subgroup) could be found in the cultivated group. A very close relationship between ‘Huagaili’ and ‘Miansuan’, and a close relationship between ‘Anli’ and a wild accession, P. ussuriensis ‘Huangshanli’ could be found in Anli subgroup. ‘Nanguoli’ and ‘Xiaowuxiang’ showed a close relationship with at least one identical allele at each locus with the exception of NH015a.     

ISSR Variation in Olive-tree Cultivars from Morocco and other Western Countries of the Mediterranean Basin

In olive tree (Olea europaea L.), 12 varieties (or cultivars) representing the main domesticated material used in Morocco and 19 olive cultivars used extensively in five countries of the western Mediterranean Basin, were analysed using inter-simple sequences repeat (ISSR) markers which had never been used previously for extensive discrimination of cultivars. Four selected primers produced a total of 26 polymorphic reproducible amplification fragments. Combinations of these ISSR markers allowed to identify 25 of the 31 cultivars. Two additional combinations were distinguished, each corresponding to three Moroccan cultivars or local varieties. Evidence of a multiclonal composition in the widely cultivated variety ‘Picholine marocaine’ was obtained by the identification of three genotypes within the four morphologically distinct clones analysed in the variety. In the UPGMA phenogram based on the proportion of shared ISSR fragments, five groups of cultivars were distinguished at the 40% critical value of similarity. Four of the groups contained varieties from various geographic origins, as the consequence of successive human migrations which favoured olive dispersion throughout the Mediterranean Basin. However, the fifth group gathered together 9 of the 12 Moroccan cultivars and very few cultivated clones from Greece and Spain. The results suggest that most of the Moroccan cultivars are closely related and likely originated from local domestication.     

Spanish melons (Cucumis melo L.) of the Madrid provenance: a unique germplasm reservoir

Melon (Cucumis melo L.) landraces of the Madrid provenance, Spain, have received national distinction for their high fruit quality and sensorial attributes. More specifically, a unique array of Group Inodorus landraces have been continuously cultivated and conserved by farmers in the municipality of Villaconejos since the 19th century. Their genetic relationships to other Group Inodorus and Flexuous melon market classes is not known, and, thus, a study was designed to determine their genetic relationships using 52 simple sequence repeat (SSR) markers, and then make genetic comparisons between these accessions and a previously published “Standard Reference Germplasm Array” (RA) containing Group Inodorus (14 Spanish and one USA), Flexuosus (1 Spanish), and Cantalupensis ( 2 USA) melon accessions. This subset consisted of 15 Spanish Group Inodorus landraces that circumscribed the genetic variation of major Spanish melon market classes (Groups Inodorus and Flexuosus), and USA commercial varieties (Groups Cantalupensis and Inodorus). Based on genetic distances, Villaconejos (Madrid) genotypes differed substantially from RA subset accessions, thus defining their genetic uniqueness. Principal component analysis (PCA) partitioned the accessions examined into four distinct groups revealing that Villaconejos black epidermis melons (landraces ‘Largo’, ‘Largo Negro Escrito’ and ‘Puchero’) were distinctly different from all other accessions examined, as cluster analysis separated Rochet market type Villaconejos’ accessions (landraces ‘Mochuelo’, ‘Mochuelo Tradicional’ and ‘Melón de Villaconejos’) from RA of the same market type. Genetic assessment of principal Spanish market classes revealed comparatively low intra-market heterogeneity in Piel de Sapo type accessions and high heterogeneity in Black and Yellow market type accessions. While a relatively high level of genetic introgression was detected between Yellow and Green market types, black epidermis market types were genetically unique. Given the uniqueness and high genetic diversity resident in Villaconejos landraces, this germplasm pool should be considered as a genetic source for broadening the comparatively narrow genetic base of Group Cantalupensis and Inodorus melon market types, especially standard commercial Spanish Group Inodorus market types (e.g., Piel de Sapo, Rochet, and Canari).     

Molecular Markers for the Classification of Switchgrass (Panicum virgatum L.) Germplasm and to Assess Genetic Diversity in Three Synthetic Switchgrass Populations

Information regarding the amount of genetic diversity is necessary to enhance the effectiveness of breeding programs and germplasm conservation efforts. Genetic variation between 21 switchgrass genotypes randomly selected from two lowland (‘Alamo’ and ‘Kanlow’) and one upland (‘Summer’) synthetic cultivars were estimated using restriction fragment length polymorphism (RFLP) markers. Comparison of 85 RFLP loci revealed 92% polymorphism between at least two genotypes from the upland and lowland ecotypes. Within ecotypes, the upland genotypes showed higher polymorphism than lowland genotypes (64% vs. 56%). ‘Kanlow’ had a lower percent of polymorphic loci than ‘Alamo’ (52% vs. 60%). Jaccard distances revealed higher genetic diversity between upland and lowland ecotypes than between genotypes within each ecotype. Hierarchical cluster analysis using Ward's minimum variance grouped the genotypes into two major clusters, one representing the upland group and the other the lowland group. Phylogenetic analysis of chloroplast non-coding region trnL (UAA) intron sequences from 34 switchgrass accessions (6 upland cultivars, 2 lowland cultivars, and 26 accessions of unknown affiliation) produced a neighbor-joining dendrogram comprised of two major clusters with 99% bootstrap support. All accessions grouped in the same cluster with the lowland cultivars (‘Alamo’ and ‘Kanlow’) had a deletion of 49 nucleotides. Phenotypic identification of greenhouse-grown plants showed that all accessions with the deletion are of the lowland type. The deletion in trnL (UAA) sequences appears to be specific to lowland accessions and should be useful as a DNA marker for the classification of upland and lowland germplasm.     

Identification of sweet cherry cultivars (Prunus avium L.) and analysis of their genetic relationships by chloroplast sequence-characterised amplified regions (cpSCAR)

Ten cpSCAR markers that show polymorphism in Prunus avium were used to fingerprint sweet cherry cultivars. The purpose of the study was also to contribute to identification and to help determine their genetic interrelationships. Samples of ‘0900 Ziraat’, a superior Turkish variety, which were collected in several locations all over Turkey, had identical cpSCAR patterns, and they resembled a common European haplotype, A. ‘Sweetheart’, ‘Summit’ and ‘Canada Giant’ and their haplotype are intermediate between the previously described haplotypes A and B, which were originally found in Central and Eastern European sweet and wild cherries, and those from Northern Turkey, respectively. The data therefore suggests a local maternal descent (within Europe and Asia Minor) of the cultivars analysed. Our results show that chloroplast DNA analysis is a straightforward way to classify cherry cultivars. We compare our results to others previously reported for sweet cherry cultivars, and conclude that cpSCAR diversity data could be considered for phylogenetic studies in this group.     

Morphologic and Agronomic Diversity of Wild Genetic Resources of Medicago sativa L. Collected in Spain

One hundred and three natural populations of Medicago L. were collected in Spain, mainly from roadsides, non-irrigated or grazed lands. This germplasm was evaluated at Montpellier (France) with control cultivars and Spanish landraces under completely random block design, replicated four times, and observed for 64 qualitative or quantitative characters. Differences between natural populations and cultivated controls are highly significant, but gene flow occurs between wild and cultivated compartment and hybrid populations were identified. On the basis of multivariable analysis, the accessions were grouped into four clusters depending on their proximity with the cultivated pool to facilitate their management and ex situ conservation. The relationship between environment of the site of collection and phenotypic characteristics of the natural populations was also discussed. Different policies of conservation of these genetic resources are suggested to avoid their disappearance even when they disappeared from the other regions of the western Mediterranean. Spanish wild pool of alfalfa, also called ‘Mielga’, appears of great interest for the breeding of alfalfa because it contains a large diversity of characteristics (prostrate habit, rhizomes) linked to tolerance to grazing or drought environment. With the need for more sustainable systems in agriculture, the erosion of natural habitats and the necessity for rehabilitation of degraded ecosystems, the importance of this wild pool is really inestimable.     

Genic SSRs for European and North American hop (Humulus lupulus L.)

Eight genic SSR loci were evaluated for genetic diversity assessment and genotype identification in Humulus lupulus L. from Europe and North America. Genetic diversity, as measured by three diversity indices, was significantly lower in European cultivars than in North American wild accessions. Neighbor Joining cluster analysis separated the hop genotypes into European and North American groups. These eight SSRs were useful in uniquely identifying each accession with the exception of two sets of European landraces and a pair of Japanese cultivars, ‘Shinshuwase’ and ‘Kirin II’. An accession from Manitoba grouped with the European (EU) cluster reflecting the group’s genetic similarity to older Manitoba germplasm used to develop ‘Brewer's Gold’ and the gene pool arising from this cultivar. Cultivars grouped closely with one of their immediate parents. ‘Perle’ grouped with its parent ‘Northern Brewer and ‘Willamette’ grouped with its parent ‘Fuggle H’. Wild American accessions were divided into two subgroups: a North Central group containing mostly H. lupulus var. lupuloides and a Southwestern group containing H. lupulus var. neomexicanus accessions. These eight SSRs will be valuable for genotype identification in European and wild American germplasm and may potentially prove useful for marker-assisted selection in hop. PCR products from four previously reported primer pairs that amplify the same intronic SSR regions as do the genic SSRs in this study were compared in eight common cultivars. Different primer pairs generated robust markers at the chs2 and chi loci. However, only the HLC-004B and HLC-006 primer pairs amplified successfully at the chs3 and chs4 loci. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic Diversity and Relationships of Japanese Peach (<Emphasis Type="Italic">Prunus persica</Emphasis> L.) Cultivars Revealed by AFLP and Pedigree Tracing

To evaluate the genetic diversity and to clarify the genetic relationships of Japanese peach cultivars, we analyzed the amplified fragment length polymorphism (AFLP) and traced the pedigree of 17 Japanese commercial peach cultivars and six traditional accessions. Sixteen AFLP primer combinations produced a total of 837 fragments and 146 polymorphic bands with a polymorphism percentage of 17.5%. All of the peach accessions could be identified from differences in at least 10 polymorphic bands. A cluster analysis showed that all the Japanese commercial peach cultivars, except ‘Kiyomi’ and ‘Jichigetsuto’, formed a major group consisting of three sub-groups. Of the six traditional accessions, four were genetically distant from the Japanese commercial peach cultivars while two accessions from China were classified into the Japanese commercial peach cultivars group. Both the AFLP analysis and pedigree tracing suggested that Japanese commercial peach cultivars are mainly derived from ‘Shanhai Suimitsuto’, one of the traditional accessions from China. Although the genetic relationships revealed by AFLP were generally in agreement with those shown by the pedigree information, some contradictions were found. Combining the AFLP results and pedigree information can provide a better understanding of the genetic relationships of Japanese peach cultivars.     

Analysis of Genetic Relationships among Turkish Cultivars and Breeding Lines of Lens culinatis Mestile Using RAPD Markers

Randomly Amplified Polymorphic DNA markers were used to determine the genetic relationships among Turkish lentil cultivars and breeding lines. Fourteen cultivars and thirteen breeding lines were evaluated to determine genetic variability using nine random 10-mer primers (among 45 primers). Forty-one reproducible bands were obtained, 54% of which were polymorphic. Genetic distances among cultivars and breeding lines were obtained from the simple matching coefficients (SM). The lowest genetic distance was observed between the cultivars of Ali Dayi and Kafkas with 5.0%, while ‘Seyran-96’ and ‘Ozbek’ had the highest genetic distance with 58.3%. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis was performed on the distance matrix using Phylip software. The dendrogram clearly showed two distinct groups. The first group is composed of Akm 565 and Akm 563. The second group contains all the cultivars and remaining eleven breeding lines.     

Relationship of European persimmon (Diospyros kaki Thunb.) cultivars to Asian cultivars, characterized using AFLPs

Sixty one persimmon (Diospyros kaki Thunb.) selections, including 17 Italian, 11 Spanish, 13 Japanese, six Korean, five Chinese, one Israeli, and eight of unknown origin, were evaluated for genetic differences by AFLP analysis. Relationships among cultivars were evaluated by UPGMA clustering, Neighbor Joining, and MultiDimensional Scaling. While similarities among groups were generally less than 0.60, both UPGMA and Neighbor Joining separated European and Asian cultivars. Spanish and Italian cultivars were not separated by any of the analyses, suggesting that they share a common gene pool, while Japanese, Chinese and Korean cultivars formed distinct clusters. Diversity within groups was greater than diversity between groups. Most cultivars were quite polymorphic (only 0.60–0.80 similarity between cultivars). In addition, the presence of several Japanese cultivars in the European group and a group of European cultivars nested between Chinese and Korean groups suggest that similar, but different progenitors were used in the development of the present European cultivars. ‘Kaki Tipo’ selections from different sources were clearly different by AFLP analysis, indicating that they are separate cultivars.     

Evaluation of genetic identity and variation of local apple cultivars (<Emphasis Type="Italic">Malus</Emphasis> × <Emphasis Type="Italic">domestica</Emphasis> Borkh.) from Spain using microsatellite markers

A collection of 114 local cultivars of Malus × domestica Borkh. from the Northwest of Spain and a group of 26 non-native commercial cultivars, were studied in order to determine the level of genetic differentiation between them, to know the population genetic structure of the three main production regions in North Spain, and to detect possible duplications, misidentifications, and intrusions of foreign cultivars into the present day Spanish apple gene pools. Ten primer pairs of microsatellite loci were selected from previous studies on apple. Allelic frequencies were used to estimate the average expected heterozygosity (Hexp) and F-statistics. A Principal Component Analysis and a Cluster Analysis were conducted in order to determine the relationships among cultivars. Considering all populations (Spanish and commercial cultivars) we found 119 alleles with the 10 microsatellites; 10 out of 119 were rare (with frequencies lower than 0.01). Spanish cultivars can be used as references for those alleles for further studies since they are available in Germplasm banks. Triploid cultivars were quite frequent, 39 out of 140, with the highest number occurring in Galicia (29 cultivars). North Spain presented a high variability for apple according to heterozygosity levels. Microsatellites have provided useful information about the singularity of Spanish apple cultivars, revealed six groups of synonymies and five introgressions of commercial cultivars.     

Assessing genetic diversity of Polish wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>) varieties using microsatellite markers

Fifty-three wheat cultivars have been genotyped using 24 SSR (simple sequence repeat) markers in order to evaluate genetic similarities among Polish wheats, i.e. 53 spring and winter cultivars; ‘Chinese Spring’ was taken as reference. ll but one SSR marker allowed to identify DNA polymorphisms, giving in total 166 alleles (including nulls), from 3 to 13 alleles per marker with mean of 7.22. Based on marker data, genetic similarities were calculated and a dendrogram was created. ‘Spring’ cultivars were less diverse than winter ones, showing the biggest similarity to ‘Chinese Spring’. Four sister cultivars (Nutka, Tonacja, Zyta and Sukces), formed a cluster of very similar materials, of which Zyta and Sukces had the highest similarity indices. Parental lines Jubilatka and SMH 2182 were more distant from each other (genetic similarity of 0.227). It was possible to differentiate all the wheats using only four SSR markers: Xgwm186, Xgwm389, Xgwm459 and Xgwm577.     

Characterization of Promising Apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) Genetic Resources in Malatya,Turkey

The study here was conducted on nearly 12,000 apricot seedlings in the Malatya Region in the Eastern part of Turkey. This region is famous for its horticulture based mainly on apricot production and the Country's highest apricot production originates from this region. The flower and fruit characteristics of all populations, which include apricot seedlings, in the region were evaluated. Based on their horticultural performances, 13 genotypes were selected, of which seven were considered as apricots served in dried form and six as in table consumption form. Among the selected genotypes, the fruit weight ranged between 28.5 and 71.19 g, soluble solids ranged between 12.7 and 26.5%, while the range in total acidity was between 0.35 and 1.80% and fruit development period was between 87 and 183 days. To determine the selected genotypes performance in a similar environment, they were grafted on to 4-year-old rootstocks. The results from these combinations showed that there was some decrease, especially in fruit size and soluble solids, in the genotypes performance when compared to the results of the initial observations. Some differences were also detected in taste, fruit shape, pit shape, fruit flesh firmness, skin and flesh colors. The dry fruit yield was determined as 22.50–28.36% for the selected dry apricot genotypes. The dry fruit yield of all seven genotypes considered for dry consumption were similar to ‘Hacıhaliloğlu’ and higher than ‘Canino’, which were evaluated as control cultivars.     

Microsatellite Markers Revealed the Genetic Diversity of an Old Japanese Rice Landrace ‘Echizen’

Landraces of rice (Oryza sativa L.) are valuable sources of genetic variation that have been lost in advanced cultivars. Seeds of a rice landrace stored for almost 100 years were found on Sado Island in Niigata prefecture, Japan. This report aims to present basic data on the genetic variation of this landrace, which was known as ‘Echizen’. Five samples of ‘Echizen’, consisting of two old samples, one sample maintained on farm, and two lines regenerated from old seeds were compared with other advanced cultivars and landraces using 19 microsatellite markers. Among the five samples of Echizen, the two stored samples showed greater diversity than the other samples. Cluster analysis based on the UPGMA method also showed that old Echizen was a diverse landrace that could cover the genetic diversity of most Japanese rice cultivars.     

Genetic diversity and relationships of common apricot (Prunus armeniaca L.) in China based on simple sequence repeat (SSR) markers

The common apricot (Prunus armeniaca L.) is adaptable to the diverse geographical areas throughout northern China where the original center for common apricot is worldwide. The diversity of 94 apricot samples, including 66 typical Chinese local cultivars, four kernel-using apricots, thirteen cultivars of Xinjiang (belong to Central Asian groups), ten exotic cultivars and one black apricot (Prunus dasycarpa Ehrh.) accession, were investigated using 21 simple sequence repeat markers. Totally, 662 genotypes were identified in the set of tested 93 common apricot cultivars, with an average of 31.52 genotypes per locus. The allele diversity per locus, with an average allele number of 15.14, and the heterozygosity rates, with an average expected heterozygosity value for the sample set of 0.792, were found to be higher than those in previous studies, implying that Chinese apricot germplasms presented a high level of genetic diversity. The clustering analysis and principal coordinate analysis outlined the genetic relationships of apricot cultivars tested from different geographical distributions. The results supported the traditional classification of apricot germplasm based on the ecological types, and showed that the richest diversity existed in the northern China and northwestern China local cultivars among common apricot germplasm resources tested. This study will facilitate the understanding of the evolution relationships and the conservation strategies of the genetic diversity in apricot in China.     

Ambiguous genetic relationships among coconut (<Emphasis Type="Italic">Cocos nucifera</Emphasis> L.) cultivars: the effects of outcrossing,sample source and size,and method of analysis

A prior analysis of eight coconut cultivars with 15 microsatellite (SSR) markers drew unexpected relationships between two of the out-crossing tall cultivars evaluated: ‘Atlantic Tall’ and ‘Panama Tall’. We further investigated the relationships between these eight cultivars by increasing the number of individuals studied (particularly for ‘Atlantic Tall’ and ‘Panama Tall’), by including 28 more molecular markers, and by adding two other cultivars to our analysis. Our results show that five to ten coconut individuals do not represent a dependable sample to withdraw conclusions regarding cultivar/variety relationships, particularly when studying out-crossing genotypes. As suggested in the prior study, a high level of hybridization was observed between the ‘Atlantic Tall’ and ‘Panama Tall’ cultivars. However, at this time we were able to identify distinct groups for each one of these two cultivars. The two clustering methods used (Neighbor Joining, NJ and Unweighted Pair Group Method with Arithmetic mean, UPGMA) produced dendrograms that resolved contrasting cultivar relationships, especially for the ‘Atlantic Tall’ and ‘Panama Tall’ cultivars. We discuss the implications of our results in regard to current scenarios of coconut domestication and future considerations when assessing genetic relationships among different varieties.