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Accueil du site → Doctorat → Allemagne → 2020 → Environment-dependent regulation of flowering time in a barley (Hordeum vulgare L.) MAGIC population

Rheinischen Friedrich-Wilhelms-Universität Bonn (2020)

Environment-dependent regulation of flowering time in a barley (Hordeum vulgare L.) MAGIC population

Pesaran Afsharyan, Nazanin

Titre : Environment-dependent regulation of flowering time in a barley (Hordeum vulgare L.) MAGIC population

Auteur : Pesaran Afsharyan, Nazanin

Université de soutenance : Rheinischen Friedrich-Wilhelms-Universität Bonn

Grade : Doktorin der Agrarwissenschaften (Dr. agr.) 2020

Résumé partiel
Barley (Hordeum vulgare L.) is used as a source for food and feed and is the fourth widely cultivated cereal world-wide. Flowering time is a complex trait controlled by endogenous and environmental factors that marks switching of plant life cycle from vegetative to reproductive development. Flowering time mechanism has important role in crop adaptation to environment and abiotic stressors including heat and drought and has an impact on crop yield. Flowering time in barley, as a model for small grain cereals, is extensively studied. Nevertheless, what is known about its flowering time mechanism in response to environment is under-represented compared to model plants such as Arabidopsis thaliana. Therefore, the present thesis aims to improve understanding of environment-dependent regulation of flowering time in barley and provide insights into novel flowering time regulators. For this purpose a series of approaches were employed aiming to 1) better understand the interconnected dynamics of epistasis and environment using a MAGIC population and look for novel regulators ; 2) identify candidate gene(s) underlying novel barley flowering time QTL ; 3) investigate effect of flowering time genetic regions on yield-related traits under different environments. Spring barley MAGIC population was used in three detailed studies as plant material. This population can provide sufficient diversity and mapping power to study a complex trait such as flowering time and is constructed of an eight-way cross of barley landraces known as “founders of German barley breeding” and one elite cultivar Barke. The first study focused on QTL, epistasis and environment interaction regulation in flowering time pathway of barley under different environments including field and semi-controlled conditions. A set of 534 spring barley MAGIC DH lines were used for analyzing of quantitative trait loci (QTLs), epistatic interactions, QTL × environment interactions, and epistasis × environment interactions effects with single SNP and haplotype approaches. Results of this study, revealed overall 18 QTLs and 2,420 epistatic interactions which included regions for major genes such as Ppd-H1, Vrn-H1, Vrn-H3, and denso/sdw1. Distinguishable epistatic interactions were detected in field and semi-controlled conditions and findings from analysis of QTL × environment interactions and epistasis × environment interactions suggested the influence of temperature on regulators of flowering time pathway. Additionally, the results revealed a novel QTL harboring a flowering-delaying allele on chromosome 1H, engaged in epistatic and environment interactions, which we named “HvHeading”. The findings showed that this region was involved in epistasis and epistasis × environment interactions with regions harboring Ppd-H1, Vrn-H3, and Vrn-H1 and denso/sdw1 suggesting that it might have an important role in environment-dependent regulation of flowering time in barley. The second study aimed to investigate the newly-detected QTL HvHeading to identify the underlying candidate gene(s) by a targeted background effect elimination approach based on epistasis.

Sujets : MAGIC-Population, Blütezeit, Gerste, Interaktion mit der Umwelt, Epistase, HvHeading, MAGIC population, Flowering time, barley, environment interaction, epistasis

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Page publiée le 10 novembre 2021