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Genetic mapping of diagnostic markers for the Lg 2 locus conferring ligules in Triticum aestivum L. and derived from Aegilops tauschii Coss.

Amagai, Y., Kuboyama, T., Watanabe, N.
Euphytica 2017 v.213 no.3 pp. 59
Aegilops tauschii, Hordeum vulgare, Triticum aestivum, alleles, barley, chromosome mapping, hexaploidy, loci, mutants, nucleotide sequences, phenotype, plant breeding, progeny, wheat
It has been suggested that the non-allelic lg ₂ and Lg ᵗ alleles, that confer liguleless phenotypes, are present in chromosome 2D. We hypothesized that the naturally occurring liguleless phenotype present in polyploid wheat was a typical example of loss of dominant duplicated alleles, a process that has been described as genetic diploidisation. In the present study, we obtained the base sequence of the candidate of Lg ₂ gene through a “blastn” query with the upstream region of HvLG, the candidate gene sequence for the ligule locus in barley (Hordeum vulgare), and developed deletion markers of the Lg ₂ locus from Ae. tauschii. We applied the deletion markers to locate the Lg ₂ locus in hexaploid wheat. The F₂ progeny of ANK-33/SynW-5 segregated in a 3 liguled:1 liguleless ratio. The Lg ₂ gene was completely linked to markers G3489_2DL12del and G3489_2DL11del and segregated in a 1:2:1 ratio. Liguleless Mutant, a liguleless mutant of Aegilops tauchii, was determined by the dominant Lg ᵗ gene. In Ae. tauschii, the F₂ progeny of KU2126/Liguleless Mutant, marker Atlg_2DL19del segregated in a 1:2:1 ratio independently of the 3 liguleless:1 liguled segregation. The results indicate that three deletion markers can be used to mark the Lg ₂ locus in chromosome 2D of synthetic and hexaploid wheat.