Comparative analysis of traditional and modern apricot breeding programs: A case of study with Spanish and Tunisian apricot breeding germplasm

Traditional plant breeding is based on the observation of variation and the selection of the best phenotypes, whereas modern breeding is characterised by the use of controlled mating and the selection of descendants using molecular markers. In this work, a comparative analysis of genetic diversity in a traditional (Tunisian) and a modern (Spanish) apricot breeding programme was performed at the phenotypic and molecular level using simple sequence repeat (SSR) markers. Seven phenotypic traits were evaluated in 42 Tunisian apricot accessions and 30 genotypes from the Spanish apricot programme. In addition, 20 SSR markers previously described as linked to specific phenotypic traits were assayed. Results showed that modern breeding using controlled crosses increases the size of the fruit. The fruit weight average observed in the Tunisian cultivars was of 20.15 g. In the case of traditional Spanish cultivars the average weight was 47.12 g, whereas the average weight of the other progenitors from France, USA and South Africa was 72.85 g. Finally, in the new releases from the CEBAS-CSIC breeding programme, the average weight was 72.82 g. In addition, modern bred cultivars incorporate desirable traits such as self-compatibility and firmness. Cluster and structural analysis based on SSR data clearly differentiates the genotypes according to their geographic origin and pedigree. Finally, results showed an association between some alleles of PaCITA7 and UDP96003 SSR markers with apricot fruit weight, one allele of UDAp407 marker with fruit firmness and one allele of UDP98406 marker with fruit ripening

Loss of genetic diversity as a signature of apricot domestication and diffusion into the Mediterranean Basin

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699In order to reduce energy waste for artificial lights and subsequent air conditioning in plant growth chambers, the aim of this preliminary study was to evaluate the feasibility of growing the microvine under 100% of LED illumination. Plant growth under two different LED lights was compared amongst each other and with plants maintained in greenhouse conditions. Regarding the impact on the reproductive and vegetative systems, the study showed that LED light is suitable to grow microvines in confined environments. Plants exposed to LED light exhibited similar leaf emergence rate but reduced vegetative and reproductive organ size compared to plants grown in the greenhouse. Photosynthesis for plants exposed to LED light was higher than what is usually observed on grapevine under natural conditions

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

Les ressources génétiques de l'abricotier en Tunisie et leur relation avec la variabilité méditerranéenne

MONTPELLIER-SupAgro La Gaillarde (341722306) / SudocSudocFranceF

Transcriptional analyses of root responses under soil water stress of one-year old apple cultivars

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresGlobal climate change may lead to longer or more frequent episodes of extreme temperatures and drought, thus threatening plant crops. Thus, we focused on apple tree aiming to identify the molecular mechanisms that are triggered when trees face water soil deficit. We focused on differentially expressed transcripts (DET) in roots, between well-watered trees compared to trees grown under soil water deficit either moderate (MS) and severe (SS). Two apple cultivars, ‘Starkrimson’ (ST) and ‘Granny Smith’ (GS), with contrasted behavior under water deficit, were grafted on M9 rootstock and grown in pots under controlled conditions. Roots were sampled when transpirable soil water (FTSW)=0.5 and FTSW=0.2 were reached, for MS and SS stress, respectively. RNA was extracted and analyzed using the AryANE micro-array apple chip to identify DET response to moderate and severe soil water deprivation. Among DET in roots, 209 up and 137 down-regulated genes were common to both cultivars under MS while 148 up and 542 down-regulated genes were common to both cultivars under SS. DET linked to the response to osmotic stress were observed at MS, especially signal sensors proteins kinases and phosphatases which were up-regulated. As expected, DET related to abscissic acid (ABA) were highly expressed under water deficit conditions, both ABA-dependent (ADP) and ABA-independent pathways (AIP) being stimulated. ABA biosynthesis was activated in both genotypes in MS, even though to a lesser extent in ST than in GS. However, these transcripts were no more differentially expressed in SS, suggesting that other mechanisms are involved under SS. Specific DET to each genotype were also observed. ST had a higher number of upregulated DET at MS and downregulated DET at SS than GS. Such results prove that even when grafted on the same rootstock, we notice a significant difference on the ST and GS roots system response to the soil water deficit evidencing that root systems (here M9) response to the soil water deficit depends on the grafted scion, probably because of different transpiration and regulation in response to soil water deprivation of the two scion genotypes. Further analyses are currently performed to decipher DET in aerial organs

Population structure and core collection construction of apricot (Prunus armeniaca L.) in north Africa based on microsatellite markers

North Africa enclosed original apricot genetic resources with the cohabitation of grafting and seed-propagated accessions. In this study, we assessed the genetic diversity and population structure of 183 apricot accessions using 24 microsatellite markers distributed evenly in the Prunus genome. A total of 192 alleles and a high level of gene diversity (0.593) were detected among the whole panel. Genetic structure analysis revealed the presence of four genetic clusters. We also found that both geographical origin and mode of propagation are important factors structuring genetic diversity in apricot species. Results confirmed the presence of gene exchange between the northern and southern countries of the Mediterranean Basin. Subsequently, a core collection of 98 accessions based on M (maximization) strategy showing 99.47% of allele retention ratio was constructed. No significant differences for Shannon’s information index and Nei’s diversity index were observed between the core and entire collections. Our results provide an effective aid for future germplasm preservation and conservation strategies as well as genetic association studies development in relation to phenotypic dat

Apricot genetic resource management. New prospects offered by phylo-geographic and association genetic approaches. Application in the mediterranean basin germplasm

International audienc

Apricot genetic resource management. New prospects offered by phylo-geographic and association genetic approaches. Application in the mediterranean basin germplasm

International audienceApricot (Prunus armeniaca L.) was introduced from China to the Mediterranean region through at least two majn routes and a large number of cultivars are here developed in the different countries. In order to characterize the actual Mediterranean genetic variability, 251 apricot accessions from France, Spain, Tunisia, and Turkey were investigated with a common set of markers. Twenty five SSR loci, covering the whole Prunus genome were chosen according to their expected polymorphism. Our results confirmed that SSR markers are efticient tools for fingerprinting cultivars and for determining the genetic structure of apricot Mediterranean populations as well. On the base of a Bayesian analysis four main phylogeograpbical groups have been identified: Tunisian, Enropean (Mediterranean & continental), Turkish and a diversification group joining accessions from central Asia to Europe

Genetic diversity and differentiation of grafted and seed propagated apricot (Prunus armeniaca L.) in the Maghreb region

UMR 1334 AGAP : Equipe AFEF ‘Architecture et Fonctionnement des Espèces fruitières’ ; Team AFFS ‘Architecture and Functioning of Fruit Species’Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699Apricots from Maghreb region (Algeria, Morocco and Tunisia) in North Africa are both clonally (by graft-ing) and seed propagated that are mainly grown in oasis agroecosystems. Are these two apricot groups genetically distinct or closely related, as previously suggested? We sought an answer to this question by analysing the genetic diversity and differentiation of 183 apricot accessions from Algeria, Morocco and Tunisia using 24 nuclear microsatellite markers distributed throughout the eight linkage groups of the Prunus genome. A total of 191 alleles were detected in the studied accessions. Similar high genetic diversity parameters were observed among all apricot geographic groups, revealing that there is high genetic variability in apricots from the Maghreb region. We conducted hierarchical clustering using the Neighbor-joining algorithm and showed that apricot can be classified according to its geographic origin and propagation mode in Maghreb. Despite this, we showed that both grafted and seed propagated apri-cots shared a common gene pool. Overall our results will help to improve management and conservation of Maghrebian apricot genetic resources

Comparative analysis of traditional and modern apricot breeding programs: A case of study with Spanish and Tunisian apricot breeding germplasm

Traditional plant breeding is based on the observation of variation and the selection of the best phenotypes, whereas modern breeding is characterised by the use of controlled mating and the selection of descendants using molecular markers. In this work, a comparative analysis of genetic diversity in a traditional (Tunisian) and a modern (Spanish) apricot breeding programme was performed at the phenotypic and molecular level using simple sequence repeat (SSR) markers. Seven phenotypic traits were evaluated in 42 Tunisian apricot accessions and 30 genotypes from the Spanish apricot programme. In addition, 20 SSR markers previously described as linked to specific phenotypic traits were assayed. Results showed that modern breeding using controlled crosses increases the size of the fruit. The fruit weight average observed in the Tunisian cultivars was of 20.15 g. In the case of traditional Spanish cultivars the average weight was 47.12 g, whereas the average weight of the other progenitors from France, USA and South Africa was 72.85 g. Finally, in the new releases from the CEBAS-CSIC breeding programme, the average weight was 72.82 g. In addition, modern bred cultivars incorporate desirable traits such as self-compatibility and firmness. Cluster and structural analysis based on SSR data clearly differentiates the genotypes according to their geographic origin and pedigree. Finally, results showed an association between some alleles of PaCITA7 and UDP96003 SSR markers with apricot fruit weight, one allele of UDAp407 marker with fruit firmness and one allele of UDP98406 marker with fruit ripening