Verifying the reliability of hybrid issued from the cross “Picholine marocaine clones X Picholine du Languedoc”

In order to verify the reliability of hybrid population issued from crossing between 3 clones of "Picholine marocaine" cultivar and the "Picholine du Languedoc" cultivar, the descendants and their parents wereanalysed using 35 microsatellite loci. No offspring resulted from self crossing of "Picholine marocaine" cultivar and 218 descendants among 220 analysed are legitimate. This study showed clearly a segregating population and may be used as a genetic material for linkage map construction and for phenotyping resistance traits related to Spilocaea oleagina disease

Rôle du métabolisme phénolique dans la défense de l’olivier à la maladie de l’oeil de paon causée par Spilocaea oleagina

In order to search the role of phenolic metabolism in the defence of the olive- tree to Spilocaea oleagina, three defence components (soluble phenolics, cell well-bound phenolics, lignin) as well as phenylalanine ammonia-lyase (Pal, key enzyme of the phenolic metabolism) were studied in a resistant cultivar (Picholine du Languedoc) and a susceptible cultivar (Moroccan Picholine). The inoculation of olive-tree leaves by Spilocaea oleagina induces a foliar necrosis whose speed of onset and expansion distinguishes clearly the two studied cultivars according to their behaviour to the leaf-spot disease. For the resistant cultivar, these symptoms are composed of small necrotic lesion, whereas, for the susceptible cultivar, they appear as extended necrotic spots. All these symptoms are accompanied by an increase in the accumulation of the contents of soluble and parietal phenolics and the intensification of the lignifications whose speed and intensity plainly distinguish both cultivars under study. The induction of PAL activity is fast and intense in the resistant cultivar, whereas it is late and weak in the susceptible cultivar. These results reveal that the response of phenolic metabolism to the resistance of the olive tree to the leafspot disease appears to occur in the early stages of infection leading to an increase biosynthesis of the contents of three defence components (soluble phenolics, parietal phenolics and lignin).Afin de rechercher le rôle du métabolisme phénolique dans la défense de l’olivier vis-à-vis de la maladie de l’oeil de paon trois composantes de défense constitutives et induites (phénols solubles, phénols liés à la paroi, lignine) ainsi que la phénylalanine ammonialyase (PAL) ont fait l’objet d’études chez une variété résistante (Picholine du Languedoc) et une variété sensible (Picholine marocaine). L’inoculation des feuilles de l’olivier par Spilocaea oleagina se traduit par des symptômes nécrotiques dont la vitesse d’apparition et d’extension distingue clairement les deux variétés étudiées selon leur comportement à la maladie de l’œil de paon. Chez la variété résistante, ces symptômes consistent en petites lésions nécrotiques alors que chez la variété sensible, ils apparaissent sous formes de tâches nécrotiques étendues qui se généralisent à l’ensemble de la feuille. Ces symptômes s’accompagnent par une augmentation de l’accumulation des teneurs en phénols solubles et pariétaux et par l’intensification de la lignification dont la rapidité et l’intensité distingue clairement les deux variétés étudiées. L’induction de l’activité PAL est rapide et intense chez la variété résistante alors qu’elle est tardive et faible chez la variété sensible. Ces résultats montrent que l’intervention du métabolisme phénolique dans la résistance de l’olivier au Spilocaea oleagina semble se manifester dans les premiers stades de l’infection en aboutissant à la biosynthèse de quantités importantes en phénols solubles et pariétaux et en lignine

Grafting versus seed propagated apricot populations: two main gene pools in Tunisia evidenced by SSR markers and model-based Bayesian clustering

Apricot was introduced into the Mediterranean Basin from China and Asian mountains through the Middle-East and the Central Europe. Traditionally present in Tunisia, we were interested in accessing the origin of apricot species in the country, and in particular in the number and the location of its introductions. A set of 82 representative apricot accessions including 49 grafted cultivars and 33 seed propagated ‘Bargougs’ were genotyped using 24 microsatellite loci revealing a total of 135 alleles. The model-based Bayesian clustering analysis using both Structure and InStruct programs as well as the multivariate method revealed five distinct genetic clusters. The genetic differentiation among clusters showed that cluster 1, with only four cultivars, was the most differentiated from the four remaining genetic clusters, which constituted the largest part of the studied germplasm. According to their geographic origin, the five identified groups (north, centre, south, Gafsa oasis and other oases groups) enclosed a similar variation within group, with a low level of differentiation. Overall results highlighted the distinction of two apricot gene pools in Tunisia related to the different mode of propagation of the cultivars: grafted and seed propagated apricot, which enclosed a narrow genetic basis. Our findings support the assumption that grafting and seed propagated apricots shared the same origin

Microsatellite markers for identification of a group of italian olive accessions

Cultivar characterization for fruit trees certification requires fast, efficient and reliable techniques. Microsatellite markers (SSR) were used in the molecular characterization of 23 genotypes of Olea europaea subsp europaea. The DNA from the olive cultivars was analyzed using nine pre-selected SSR primers (GAPU59, GAPU71A, GAPU71B, GAPU103A, UDO99-01, UDO99-12, UDO99-28 and UDO99-39) and revealed 29 alleles, which allowed each genotype to be identified. In the dendrogram, the nine primers allowed the 23 olive genotypes to be grouped into subgroups corresponding to the same cultivar denominations. SSR markers proved to be efficient and reliable for the molecular characterization of Italian olive cultivars.A caracterização de cultivares na produção de mudas certificadas exige técnicas rápidas, eficientes e confiáveis. Marcadores microssatélites (SSR) foram utilizados objetivando a caracterização molecular de 23 genótipos de Olea europaea subsp europaea. O DNA das cultivares foi analisado por meio de nove primers SSR pré-selecionados (GAPU59, GAPU71A, GAPU71B, GAPU103A, UDO99-01, UDO99-12, UDO99-28 and UDO99-39) e reveleram um total de 29 alelos que permitiram individualizar cada um dos genótipos. No dendrograma, os nove primers permitiram a separação dos 23 genótipos, em subgrupos. Os SSR foram eficientes e confiaveis para a caracterização molecular de cultivares italianeo de oliva

RAPD fingerprints for identification and genetic characterization of fig (Ficus carica L.) genotypes

L'identification de 21 accessions de figuier (#Ficus carica$ L.), représentant différentes variétés, a été tentée par la méthode "RAPD" (Random amplified polymorphism DNA). A la suite du test de 85 amorces sur 4 génotypes, 12 amorces ont pu être sélectionnées qui révèlent du polymorphisme. Les 19 marqueurs RAPD permettent l'identification de 17 profils de bandes. L'analyse met en évidence une erreur d'étiquetage pour une accession et confirme la synonymie des deux autres. La technique RAPD appliquée chez le figuier montre un niveau suffisant de polymorphisme pour la discrimination des génotypes, une bonne stabilité clonale et reproductibilité. La variabilité génétique observée au sein des génotypes de figuiers étudiés apparaît non structurée suggérant qu'un flux génétique aurait existé entre les populations naturelles à l'origine des cultivars. (Résumé d'auteur