DTA

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Tesi etd-06222017-113911

Type of thesis
Perfezionamento
Author
BRUNAZZI, ALICE
URN
etd-06222017-113911
Title
Exploiting the genetic diversity of Triticum urartu for the identification of genes involved in adaptation to climate change
Scientific disciplinary sector
AGR/07
Course
SCIENZE AGRARIE E BIOTECNOLOGIE - Agrobiosciences
Committee
relatore Prof. PE', MARIO ENRICO
Keywords
  • doubled haploids
  • landscape genomics
  • Triticum urartu
Exam session start date
;
Availability
completa
Abstract
Climate change urges broadening the bases of wheat diversity in order to withstand in a sustainable manner the shifting conditions in which wheat is grown. Natural populations of Triticum urartu, donor of the A genome to bread and durum wheat, represent an important reservoir of genes/alleles. Since such populations have been subjected to natural selection in evolutionary times, they are expected to harness relevant adaptive variation. In this PhD thesis, the landscape genomics approach was used with the objective to identify the genomic loci responsible for local adaptation. A collection of 428 natural accessions of T. urartu from seed banks worldwide and representing the distribution of the Au genome across the Fertile Crescent was assembled. Sampling sites were used into a geographic information systems (GIS) analysis to extract environmental information relative to T. urartu populations. A most limiting factor analysis allowed the identification of the most divergent sampling points in terms of climatic conditions. The T. urartu panel was also characterized using a double-enzyme RAD sequencing protocol, producing tens of thousands of molecular markers spanning the entire draft genomic sequence of T. urartu. Geographic and molecular data were used to identify adaptive alleles through population genetics and linear regression approaches. At the same time, the full collection was sowed in order to monitor seed phenotypic variation and to increase seed availability for a future deep phenotypic characterization. A broad variation in several traits, including seeds area and perimeter was observed. Furthermore, as a promising methods for speeding up the breeding process and the release of new improved varieties, this thesis reviews the current status of research on doubled haploid production in wheat considering the methodology currently applied at the Heartland Plant Innovation Center Inc. in Kansas (USA).
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