Francois Marais , Bipin Neupane , Sagar Adhikari , Justin Hegstad , Yuan Liu , Bradley Bisek and Xuehui Li

Keywords: Triticum X Thinopyrum hybrids - Genotyping by sequencing - allopolyploid development

Abstract: D-tritipyrums (2n = 42; AABBJd J d ) are hexaploid hybrids with A and B genome chromosomes from Triticum turgidum L. var durum (2n = 28, AABB) and/or Triticum aestivum L. (2n = 42 = AABBDD) and a set of seven Jd chromosomes that derive from the J1 d and J2 d genomes of Thinopyrum distichum (Thunb.) Löve (2n = 28; J1 d J1 d J2 d J2 d ). A d-tritipyrum collection consisting of lines with diverse combinations of J d chromosomes has been derived through reassortment of the J1 d and J2 d genome chromosomes, yet not all of these chromosome sets are genetically balanced and agronomically useful. Forty-seven d-tritipyrums and seven d-tritipyrum/wheat hybrid derivatives were therefore analyzed to identify the J d genome chromosomes in each. Genome-wide sequence tags were acquired through genotyping by sequencing (GBS) and sorted with the aid of appropriate control genotypes to obtain a pool of Th. distichum associated sequence tags. Nine Th.- distichum single chromosome addition lines in hexaploid triticale were then used as reference genotypes to identify appropriate sequences for analyzing each homoeologous group within each line. Nineteen different Jd chromosome subsets were found among the lines. The “best” J d genome was identified based on plant phenotype and fertility and included chromosomes 1J2 d , 2J1 d , 3J2 d , 4J2 d , 5J1 d , 6J2 d and 7J2 d . Six phenotypically diverse d-tritipyrum lines with the selected genome will form the basis of a new breeding population and will be used as pivotal Jd genotypes to broaden its A, B and J d genome variability through backcross-based introgression.

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