A method to produce radiation hybrids for the D-genome chromosomes of wheat (Triticum aestivum L.).
Radiation hybrid (RH) mapping is based on radiation-induced chromosome breakage rather than meiotic recombination, as a means to induce marker segregation for mapping. To date, the implementation of this mapping approach in hexaploid (Triticum aestivum L.; 2n = 6x = 42; AABBDD) and tetraploid (T. turgidum L.; 2n = 4x = 28; AABB) wheat has concentrated on the production of mapping panels for individual chromosomes. In order to extend the usefulness of this approach, we have devised a method to produce panels for the simultaneous mapping of all chromosomes of the D subgenome of hexaploid wheat. In this approach, seeds of hexaploid wheat (AABBDD) are irradiated and the surviving plants are crossed to tetraploid wheat (AABB) to produce a mapping panel based on quasi-pentaploids (AABBD). Chromosome lesions in the A and B genomes are largely masked in the quasi-pentaploids due to the presence of A- and B-genome chromosomes from the tetraploid parent. On the other hand, the chromosomes from the D-genome are present in one copy (hemizygous) and allow radiation hybrid mapping of all D-genome chromosomes simultaneously. Our analyses showed that transmission of D-genome chromosomes was apparently normal and that radiation-induced chromosome breakage along D-genome chromosomes was homogeneous. Chromosome breakage levels between D-genome chromosomes were comparable except for chromosome 6D which suffered greater chromosome breakage. These results demonstrate the feasibility of constructing D-genome radiation hybrids (DGRHs) in wheat.
Riera-Lizarazu
O
O
Department of Crop and Soil Science, Oregon State University, Corvallis, OR 97331-3002, USA. oscar.riera@oregonstate.edu
Leonard
J M
JM
Tiwari
V K
VK
Kianian
S F
SF
D019457:Chromosome Breakage; D032461:Chromosomes, Plant / Q000235:genetics* / Q000528:radiation effects; D003433:Crosses, Genetic; D018744:DNA, Plant / Q000235:genetics; D005720:Gamma Rays; D005819:Genetic Markers; D018745:Genome, Plant; D011123:Polyploidy; D021101:Radiation Hybrid Mapping / Q000379:methods*; D014908:Triticum / Q000235:genetics* / Q000528:radiation effects
D018744:DNA, Plant; D005819:Genetic Markers