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Universitat de Lleida (2012)

Barley adaptation to stress prone environments

Visioni, Andrea

Titre : Barley adaptation to stress prone environments

Auteur : Visioni, Andrea

Université de soutenance : Universitat de Lleida

Grade : Doctoral thesis 2012

Résumé
Multi environment trials conducted over mapping population are often used to test genotypes in a set of environments that represent the target environmental range. The first part of this work is the evaluation of the ‘Nure’ x ‘Tremois’ double-haploid mapping population, together with an association panel comprising 185 barley varieties representative of the barley germplasm cultivated in the Mediterranean basin. Plant material was tested across eighteen site by year field trials combination, in six countries across the Mediterranean basin. Trials were growth at sites contrasting for natural rainfall (high vs low on the base of past meteorological data) or at the same site with one being rainfed and the other with supplementary irrigation. Trials conducted for two years in each one of the sites and this allowed tocollect a huge data series comprising agronomical traits defining grain yield and yield components, phenological and environmental data, subsequently used to identify genomic regions involved in barley adaptation. The 118 doubled haploid lines of the mapping population were genotyped with Diversity Array Technology® (DaRT) marker assay and subsequently a total of 15 CAPS and SSCP marker for candidate genes involved in phenology regulation and abiotic stress response were added to the linkage map based on DaRT markers. Data collected were firstly used to perform QTLs analysis with composite interval mapping for any environment/ trait combination, results showed eight QTLs for grain yield, days to heading and grain yield components. . The two mostly frequents QTLs for grain yield and days to heading were located on barley chromosome 1H (3 trials), 2H (8 trials) and 5H (5 trials) overlapping respectively HvFT3 gene, the earliness per se locus (eam6/Eps-2) and the vernalization gene Vrn_H1. A further QTL multi-environment analysis was performed and revealed that across the 18 field trials QTL for eam6/Eps-2 (2H) and Vrn-H1 (5H) were commons for days to heading and grain yield. We use all the environmental information collected to check QTLs sensitivities to co-environmental co-variables. Most of significant associations collected were related to temperature and temperature-based variables troughtout the growing cycle. Eam6/Eps-2 showed non-crossover QTL.E interaction, while for Vrn-H1 crossover interactions were revealed. The 185 barley accession were genotyped with 1536 SNPs and data collected for this population for cold resistance in two field trials in Spain an Italy, the first trial was characterized by an exceptional winter, while the second was previously know has frost-prone environment. Results from genome wide association analysis showed 13 positive associations with specific genomic regions. Interestingly several of these QTL were coincident with the position of previously mapped loci for cold tolerance, on chromosomes 2HL, 4HL and 5HL.

Mots clés : Ordi Genètica vegetal Cebada Genetica vegetal Barley Plant genetic Millora genètica Mejora genética vegetal Plant breeding

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