Genetic analysis of rootstock-mediated nitrogen (N) uptake and root-to-shoot signalling at contrasting N availabilities in tomato

Selecting rootstocks for high nitrogen acquisition ability may allow decreased N fertilizer application without reducing tomato yields, minimizing environmental nitrate pollution. A commercial hybrid tomato variety was grafted on a genotyped population of 130 recombinant inbred lines (RILs) derived from Solanum pimpinellifolium, and compared with self- and non-grafted controls under contrasting nitrate availabilities (13.8 vs 1.0 mM) in the nutrient solution. Grafting itself altered xylem sap composition under N-sufficient conditions, particularly Na+ (8.75-fold increase) concentration. N deprivation decreased shoot dry weight by 72.7% across the grafted RIL population, and one RIL rootstock allowed higher total leaf N content than the best of controls, suggesting more effective N uptake. Sixty-two significant QTLs were detected by multiple QTL mapping procedure for leaf N concentration (LNC), vegetative growth, and the xylem sap concentrations of Mn and four phytohormone groups (cytokinins, gibberellins, salicylic acid and jasmonic acid). Only three LNC QTLs could be common between nitrogen treatments. Clustering of rootstock QTLs controlling LNC, leaf dry weight and xylem sap salicylic acid concentration in chromosome 9 suggests a genetic relationship between this rootstock phytohormone and N uptake efficiency. Some functional candidate genes found within 2 Mbp intervals of LNC and hormone QTLs are discussed

Literature review. Consistency and reproductibility of bio molecular methods for the examination of tomato variety DUS tests

National audienc

Genetic analysis of root-to-shoot signaling and rootstock-mediated tolerance to water deficit in tomato

Developing drought-tolerant crops is an important strategy to mitigate climate change impacts. Modulating root system function provides opportunities to improve crop yield under biotic and abiotic stresses. With this aim, a commercial hybrid tomato variety was grafted on a geno-typed population of 123 recombinant inbred lines (RILs) derived from Solanum pimpinellifolium, and compared with self-and non-grafted controls, under contrasting watering treatments (100% vs. 70% of crop evapotranspiration). Drought tolerance was genetically analyzed for vegetative and flower-ing traits, and root xylem sap phytohormone and nutrient composition. Under water deficit, around 25% of RILs conferred larger total shoot dry weight than controls. Reproductive and vegetative traits under water deficit were highly and positively correlated to the shoot water content. This association was genetically supported by linkage of quantitative trait loci (QTL) controlling these traits within four genomic regions. From a total of 83 significant QTLs, most were irrigation-regime specific. The gene contents of 8 out of 12 genomic regions containing 46 QTLs were found significantly enriched at certain GO terms and some candidate genes from diverse gene families were identified. Thus, grafting commercial varieties onto selected rootstocks derived from S. pimpinelli-folium provides a viable strategy to enhance drought tolerance in tomato. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Optimisation of apricot breeding by a joint conventional and molecular approach applied to the main agronomics traits

Preliminary results of the European ABRIGEN (FAIR6 CT98-4345) are presented. The general objective is the optimization of the apricot selection methodology in order to improve breeding strategies. It is based on a multidisciplinary research dedicated to the genetic determinism of the main agronomic traits, the quality of the fruit and the resistance to major diseases. It is mainly focus on: (i) the inheritance of the major agronomic traits, fruit quality and resistance to sharka and bacteriosis; (ii) the analysis of possible linkages or associations between traits; (iii) the identification of associated molecular markers. The work is based on the analysis of a 9x9 diallel cross, with 61 families and more than 3700 offspring. Teams including geneticists, development biologists, plant pathologists, physiologists and molecular biologists have been joined to reach the objective

Prospection characterisation and assessment of apricot genetic resources in the mediterranean region for the production in arid and semi-arid areas

Under the frame of an EEC - INCO-DC programme, 'APRIMED' research project is under development with the objective to characterize, to preserve and to identify the apricot genetic resources in part of the Mediterranean Region (Turkey, Spain, Italy, France, Morocco and Tunisia). An integrated and multidisciplinary approach divided in 3 main tasks has been developed. Prospection and preservation of genetic resources - During the prospection, 103 accessions have been identified in Morocco and 58 in Tunisia; while the preservation of 430 clones has been performed in France, 279 in Italy and 94 in Turkey. Characterization - A phenotypic characterization under UPOV descriptor has been achieved on 204 clones. A molecular characterization has been applied onto a set of 83 accessions by means of 4 microsatellites. Assessment of agronomic performances - The agronomic value has been accessed onto a total of 242 clones and partly investigated on 158 clones - Flower fertility has been investigated on the productive clones. Male sterility and interincompatibility groups have been identified. Chilling requirements and Floral anomalies measurements were optimized and applied to the germplasm. Fruit quality traits have been characterized in France, Italy, Tunisia and Turkey. Resistance to pest and disease has been characterized on a part of the gene-pool against sharka, Monilia and Capnodis tenebrionis

Prospection, characterization and assessment of apricot genetic ressources in the mediterranean region for the production in arid and semi-arid areas

National audienceUnder the frame of an EEC - INCO-DC programme, 'APRIMED' research project is under development with the objective to characterize, to preserve and to identify the apricot genetic resources in part of the Mediterranean Region (Turkey, Spain, Italy, France,. Morocco and Tunisia). An integrated and multidisciplinary approach divided in 3 main tasks has been developed. Prospection and preservation of genetic resources - During the prospection, 103 accessions have been identified in Morocco and S8 in Tunisia; while the preservation of 430 clones has been performed in France, 279 in Italy and 94 in Turkey

Prospection, charaterization and assessment of apricot genetic resources in the mediterranean region for the production in arid and semi-arid areas

International audienc