Commercial Iranian olive cultivars: morphological traits,molecular diversity,and genetic structure

Iran is considered to have a unique gene pool of different fruit and nut species including olive (Olea europaea L.). In this study, we used 22 previously developed microsatellite (simple sequence repeat; SSR) markers for olive to evaluate the level of genetic variation and to produce identification keys for 63 Iranian accessions of olive belonging to 17 groups of cultivars. Based on morphological features, the number of flowers per inflorescence, fruit weights, endocarp weights, oil percentages, and flesh weights per endocarp had the highest coefficient of variation values, indicating the large extent of morphological variability among the 63 Iranian olive cultivars studied. All 22 microsatellite (SSR) markers revealed a high level of polymorphism, with a mean polymorphic information content (PIC) value of 0.511. Analyses of genetic structure among the 63 olive accessions were carried out using model-based methods, which showed a tendency for geographical clustering. Ten SSRs out of the 22 were successful for the identification of unique ID keys for 52 of the 63 accessions. In most cases, there was disagreement between the molecular data and the morphological data. These results could be used to reconstruct and maintain a collection of olive for future breeding programmes.     

SSR markers reveal the uniqueness of olive cultivars from the Italian region of Liguria

Twenty-three important Ligurian olive accessions corresponding to 16 cultivars were studied using 12 SSR markers and 40 Mediterranean cultivars were included in the study in order to investigate the relationships between Ligurian and Mediterranean germplasm. All SSRs produced polymorphic amplifications. One hundred and forty-nine alleles were found in the 63 accessions analysed. Twenty-two alleles were specific to germplasm from Liguria and of these 12 were unique to single cultivars. Heterozygosity and discriminating power calculated in this regional germplasm were high on average (0.70 and 0.74) and not so much lower than the values in the total sample that includes cultivars from different Mediterranean countries (0.77 and 0.88 respectively). No cases of genetic identities were found between Ligurian and Mediterranean accessions. Several cases of homonyms and synonyms within the Ligurian germplasm were explained. Cluster analysis generally revealed a clear discrimination of the profiles from Liguria and Italy with respect to the cultivars from other Mediterranean countries. Only one Ligurian cultivar, “Negrea”, appeared to have a different origin, grouping with the Mediterranean cultivars.     

越橘叶片转录组SSR发掘及其多态性研究

对高丛越橘品种‘布里吉塔’叶片转录组序列进行了简单重复序列（SSR）位点搜索和分析,发现了22 058个SSR位点,总发生频率为21.32%。SSR重复类型以二核苷酸发生频率最高（77.70%）,三核苷酸次之（21.45%）。选用53对SSR引物在8个越橘属植物中进行PCR扩增,筛选出15对条带清晰且能稳定扩增的SSR核心引物。使用核心引物对39份越橘属种质进行分析,有效等位基因数最大值为7.11（VcSSR19）,最小值为1.41（VcSSR41）,平均值为3.90。香农多样性指数变化范围是0.64 ~ 2.31,平均值为1.55。观察杂合度和期望杂合度的变化范围分别是0.050 ~ 0.900和0.293 ~ 0.870,平均值分别为0.457和0.677。使用5对引物可以完全区分39份种质中的38份。南高丛越橘品种‘莱格西’和‘蓝雨’与蔓越橘品种、越橘属野生种具有更近的亲缘关系,是与野生种进行杂交育种的合适种质。     

Ampelographic and genetic characterisation of ancestral grapevine (Vitis vinifera L.) accessions present in the Umbria Region (Central Italy)

Summary

During an ongoing effort to recover and preserve local germplasm, 14 accessions of indigenous minor grapevine (Vitis vinifera L.) cultivars from the Umbria Region, Central Italy, were chosen because they had been neglected and were threatened with extinction. Their phenotypic and genetic characteristics were evaluated through an ampelographic study of their shoots, mature leaves, bunches, and berries and by genomic analysis using an international set of nine microsatellite (simple sequence repeat; SSR) markers (VVS2, VVMD5, VVMD7, VVMD27, VrZAG62, VrZAG79, VVMD25, VVMD28, and VVMD32). Comparisons of the SSR profiles of all 14 accessions with grapevine accessions in several databases permitted the identification of unique genotypes, as well as possible synonyms. Information on these older, neglected cultivars will help to reduce the genetic erosion of grapevine germplasm, improve conservation and possible recovery, and assist in the future production of new, distinctive wines.     

Agronomic evaluation of seedlings from crosses between the main Spanish olive cultivar ‘Picual’ and two wild olive trees

Summary

Until recently, olive breeding programmes have been based exclusively on cultivated olive germplasm (Olea europaea subsp. europaea var. europaea), in contrast to breeding in other fruit crops where the use of wild relatives has been widely reported. In this study, ten agronomic traits were evaluated in two progenies derived from controlled crosses between the Spanish olive cultivar ‘Picual’ (female) and two wild (O. europaea subsp. europaea var. sylvestris) genotypes (males). The results of this evaluation were compared with the progenies of crosses between ‘Picual’ (female) and the three cultivars, ‘Sikitita’, ‘Meski’, and ‘Zaity’ (male). The two ‘Picual’ × wild genotype progenies had the highest mean values for vigour traits (i.e., tree height and trunk diameter). Progenies from both ‘Picual’ × wild genotype crossess also showed the highest percentages of trees (53.8% and 37.5%) with a short juvenile period, compared to the progenies from crosses between ‘Picual’ and each of the three cultivars ‘Sikitita’, ‘Meski’, and ‘Zaity’ (0%, 5%, and 3.6%, respectively). Significant differences were also observed between progenies in fruit traits as well as in oil contents and fruit weights. Progenies from both crosses with wild olive showed lower values for the fruit traits evaluated than the cultivated olive progenies. However, significant improvements were achieved compared to fruit traits in the wild parents. The implications of these results for the future use of wild germplasm in olive breeding programmes are discussed.     

Assessment of genetic diversity of Latvian and Swedish sweet cherry (Prunus avium L.) genetic resources collections by using SSR (microsatellite) markers

Three previously described highly polymorphic SSR (microsatellite) primer pairs were tested on 126 sweet cherry (Prunus avium L.) accessions to adapt a fast, reliable method for preliminary screening of sweet cherry germplasm collections and to compare two sweet cherry germplasm collections: at the Latvia State Institute of Fruit-Growing, Dobele (LIFG-Dobele) and at the Division of Horticultural Genetics and Plant Breeding at Balsgård, Department of Crop Sciences, Swedish University of Agricultural Sciences (SLU-Balsgård). The SSR loci were highly polymorphic with 4–10 different alleles and 5–18 genotypes. Heterozygosity values ranged from 0.431 to 0.809, gene diversity (PIC) values ranged from 0.400 to 0.753, and the discriminating power of each locus varied from 0.631 to 0.894. The combined discriminating power of all loci was highly effective (0.996). Sixteen identical accession groups with the same allele profile were discovered in both collections. This study demonstrated that SSR fingerprinting with the three primer pairs tested, can be used for preliminary characterization of sweet cherry germplasm collections.     

不同生态类型西瓜种质资源遗传多样性的SSR分析

采用SSR分子标记技术对96份不同生态型西瓜种质资源的遗传多样性进行研究。从398对引物中筛选出38对扩增条带清晰、多态性高的引物分析供试材料,共得到7043条清晰可辨条带,其中多态性条带826条,占11.7%。平均每对引物对96份材料扩增出185.34条带,其中21.74条具有多态性。96份材料间的相似系数为0.42～0.99。聚类分析结果表明,野生西瓜与栽培西瓜的亲缘关系较远。在栽培品种内华北生态型、华南生态型和西北生态型西瓜的亲缘关系较近,说明我国西瓜种质资源同源性较高,遗传基础狭窄,有必要引入更多种质资源以拓宽西瓜育种背景。     

Genetic diversity among olive varieties of Southern Italy and the traceability of olive oil using SSR markers

Summary

To evaluate germplasm variability and to identify DNA profiles useful for tracing the genetic identity of olive oil, we used six Simple Sequence Repeats (SSRs) in 47 cultivated olive varieties from Central and Southern Italy. A total of 80 polymorphic SSR markers were scored and both the observed heterozygosity and the polymorphic index content were, on average, high. Genetic similarities were investigated by agglomerative hierarchical clustering and principal component analysis. The results implied that most of the olive accessions from the Campania region were genetically different from those of other Italian regions. This finding was further supported by partitioning the genetic variability using analysis of molecular variance. Furthermore, we analysed the DNA isolated from the fruit and mono-varietal oils of three cultivars. Comparative analysis of the SSR profiles revealed that these were conserved in the agro-food chain, although our data also suggested that some issues, such as the sensitivity and performance of the assay in complex mixtures, may pose limitations. Our findings extend current knowledge of Italian olive germplasm and highlight the richness and specificity of the genetic resource of olives in some regions of Southern Italy. They also provide molecular information that can be exploited for the protection of genetic material and mono-varietal oils.     

Further Work on Plant Injection for Diagnostic and Curative Purposes

Summary

Randomly Amplified Polymorphic DNA (RAPD) markers were used to evaluate genetic similarity and inter-relationship among31 acid citrus species and cultivars, including sour oranges (six accessions); ‘Yuzu’ (four accessions) andits relatives (21 accessions). Out of the 60 decamer primers screened, 27 were selected which produced 108 markers; 76 of which were polymorphic. Species or cultivar-specific RAPD markers were also found. A dendrogram based on genetic distance implied that sour oranges were very distinct from ‘Yuzu’ and its relatives. ‘Yuzu’ accessions were very closely linked to each other, however; for the other specimens genetic polymorphism could easily be detected by RAPDs and the genetic variation between accessions was quite high and revealed their different origins. In this study some RAPDs allowed the distinction of very close cultivars, for instance ‘Kabosu’ from ‘Aka kabosu’.     

Genetic diversity of apricot revealed by a set of SSR markers from linkage group G1

Eight polymorphic simple sequence repeat (SSR) markers located in the G1 linkage group of apricot (Prunus armeniaca L.) were previously developed and evaluated in a small set of cultivars. Those primers were used for studying variability in 77 apricot cultivars belonging to five different geographical groups, such as Chinese, Asian (Irano-Caucasian and Central Asian), North American, Mediterranean and Western European as well as Middle European cultivars. Six of the markers were polymorphic and revealed a total of 71 alleles ranging from 5 (aprigms11) to 20 (aprigms1) alleles per locus with a mean value of 11.83 alleles per locus. In conclusion, the SSR loci located in the G1 linkage group show a level of polymorphism which is similar to loci dispersed throughout the entire genome. The total number of alleles and the number of unique alleles were the highest in Chinese apricots and the lowest in Middle European cultivars. Heterozygosity also showed a decrease from Asia and China to Middle Europe. No association could have been observed between any SSR markers tested and plum pox virus (PPV) resistant phenotype of cultivars. PPV resistant cultivars did not form a separate clade on the dendrogram obtained by UPGMA cluster analysis. Middle European and Chinese cultivars formed separate clusters while other genotypes formed smaller multiple sub-groups or scattered among different clusters. Our results support previous hypotheses on the origin of PPV resistance in North American apricots. The allele data was also presented in a form that allowed the easy observation of allele frequencies in each geographical group at each locus. Using this data field, differences and similarities between cultivar groups can be easily assessed. The analysis demonstrated the links between the North American and Mediterranean apricot germplasm and confirmed that the Chinese and Eastern European cultivars are distantly related.     

Inter- and intra-varietal analysis of three Olea europaea L. cultivars using the RAPD technique

Summary

Characterization and selection of olive clones for the production of olive oil is essential in Portugal because of its profitable exploitation. “Moura-Serpa” is the most important Portuguese region for the production of olive oil relying on three cultivars for oil quality. These are ‘Galega Vulgar’, ‘Cordovil de Serpa’ and ‘Verdeal Alentejana’. Therefore, it is of great importance to guarantee the varietal certification of the young trees and the establishment of new orchards. Random Amplified Polymorphic DNA (RAPD) technique was used to characterize these three cultivars. Analysis started using twenty primers that allowed us to distinguish the three cultivars and to select a reduced set of primers. The selected primers were used for inter- and intra-varietal analysis and for establishing a profiling system to assay genetic diversity in other olive cultivars. The method has the potential for use in varietal certification and breeding programmes that need to analyse a high number of samples.     

Maintaining product quality in raisins throughout the introgression of powdery mildew resistance

The availability of powdery mildew-resistant raisin accessions will lower grower production costs and enhance the environment through reduced fungicide use. To achieve this objective, backcrossing has been employed with Vitis romanetii as the source of non-race-specific powdery mildew resistance. Initial crosses of powdery mildew-resistant F₁ hybrid B36-45 with seeded raisin cultivars ‘Rangspray’ and ‘Raisin de Palestine’ yielded seedless powdery mildew-resistant first-generation backcross selections C87-41 and C87-106, which were used to develop second-generation backcross populations. Principal component analyses consistently identified ‘wrinkle,’ ‘meatiness,’ ‘product attractiveness’ and ‘skin persistence’ as being the quality characteristics most important in discriminating among powdery mildew-resistant raisin accessions and commercial raisin cultivars. Raisin quality ratings were much improved across most evaluated characters in second-generation backcross families as compared with parental powdery mildew- resistant accessions C87-41 and C87-106. After two generations of backcrossing, powdery mildew-resistant raisin selections were identified with product quality characteristics similar to those of commercial raisin cultivars.     

Microsatellite marker-based identification of mother plants for the reliable propagation of olive (Olea europaea L.) cultivars in Australia

Summary

Olive production in Australia has continued to increase in recent years, however there remains a high degree of confusion on the genetic identities of the cultivars being grown. In the present study, seven microsatellite (simple sequence repeat; SSR) loci were used to identify a set of 53 olive tree samples from different sources. The microsatellite DNA profiles of all 53 tree samples, including seven unknown trees, were compared with the SSR profiles of 14 reference olive cultivars. A total of 60 fragments (alleles), averaging 8.57 alleles per microsatellite locus, were amplified. High average values were found for the observed heterozygosity, the expected heterozygosity, and the polymorphic information content (0.73, 0.74, and 0.72, respectively). While all seven microsatellite markers proved useful for characterisation and identification purposes, a combination of three SSR primer pairs (DCA9, DCA18, and EM030) was sufficient to distinguish all 53 olive samples. The microsatellite allelic profiles allowed the 53 tree samples to be grouped into 23 genotypes. The allelic profiles of 14 of these genotypes matched with their reference cultivars, while the genetic identities of the remaining nine genotypes could not be confirmed. Some of these unknown genotypes may have been derived from feral olive trees, or were due to mislabelling and/or planting errors among Australian olive cultivars. Our results confirm the usefulness of microsatellite markers as a tool for cultivar differentiation and identification, and indicate the need for reliable identification of mother plants for commercial propagation.     

Genetic assessment of apple germplasm in Bosnia and Herzegovina using microsatellite and morphologic markers

Traditional apple cultivars from Bosnia and Herzegovina (B&H), potentially diverse due to specific geographic location and history of the country, represent a possible source of valuable traits for future breeding efforts and sustainable fruit growing. A total of 39 accessions, 24 traditional B&H cultivars and 15 modern international cultivars, maintained at the ex situ apple collection “Srebrenik” in Northeast Bosnia were, investigated using 10 SSR (simple sequence repeats) markers and 23 morphologic characteristics. All the used primer pairs manage to amplify clearly distinguishable and highly polymorphic SSR alleles, in average 10.4 alleles per locus. More than two different alleles per locus were detected for seven accessions (five traditional B&H cultivars and two international cultivars). Forty one unique alleles were exclusively present within the B&H cultivars, while seven unique alleles were only detected within international cultivars. The differentiation between traditional B&H and international cultivars (Fst = 0.060; P < 0.0001) was significant, also confirmed by analyses of molecular variance (AMOVA) (f_CT = 0.092; P < 0.001). Cluster analyses of 39 apple accessions, based on 10 SSR loci, revealed that only two traditional B&H cultivars grouped tightly with international cultivars (Ljepocvjetka and Bobovec Jon), while the rest formed separate clusters. Multivariate analyses of variance (MANOVA), nonparametric multivariate analyses of variance (NPMANOVA) and analyses of similarity (ANOSIM) showed statistically significant difference in morphologic characteristics between traditional B&H cultivars and the international cultivars. Cluster analyses of 39 apple accessions, based on the morphologic data, displayed less differentiation between traditional and international accessions, in comparison to the cluster analyses based on molecular data. No correlation between the molecular and morphologic data set was detected using the Mantel test. Many of the morphologic characteristics which have been analyzed in this study have significant commercial importance, we can assume that unlike the microsatellites these traits have been under agronomic selection pressure.     

SSR-based identification key of cultivars of Olea europaea L. diffused in Southern-Italy

Olive (Olea europaea L.) is an important fruit species in Italy and Mediterranean basin constituted by a wide germplasm with a large number of cultivars present in all the Mediterranean area. SSRs are becoming the markers of choice for variability studies in olives as they are simple to perform, transferable, hypervariable, highly polymorphic and show a high information content.Olive genetic diversity was studied using 16 SSR markers on 30 cultivars diffused in Southern-Italy. Resolving Power (RP) and Power of Discrimination (PD) were calculated to evaluate the efficiency of the SSR markers investigated in studies of cultivars fingerprinting. Based on their high efficiency, two SSR markers, UDO43 and DCA16 were chosen to set up an identification key to distinguish the entire set of cultivars, confirming the high biodiversity of the Southern-Italian olive germplasm and the suitability of SSR markers in studies of cultivar diagnosis.     

云南蔷薇属部分种质资源的SSR遗传多样性研究

利用简单重复序列SSR（Simple Sequence Repeat）标记技术对42份蔷薇属（Rosa L.）种质资源（包括13份野生种、变种、变型及29份栽培品种）的遗传多样性进行了研究。用筛选出的18对SSR引物对42份材料DNA进行PCR扩增,在18个位点共检测到148个等位基因,每一位点的等位基因变幅为6~14个,平均8.2个。材料间遗传相似系数变化范围为0.282~0.892,表明在分子水平上云南省蔷薇属植物具有丰富的遗传多样性。本研究发现,在相似系数为0.456时,基于SSR标记的聚类分析可以将 13个蔷薇野生种明显分为5个组,这与植物形态学分类结果大体一致。在遗传相似系数为0.43水平上,聚类分析将42份供试材料分为5大组群;同时初步探讨了野生种之间以及野生种与栽培品种之间的遗传亲缘关系。