Affiliation:
1. National Key Laboratory of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
2. College of Life Science, Hubei University, Wuhan 430062, P.R. China.
Abstract
From dual-color genomic in situ hybridization (GISH) analysis of three trigenomic hybrids, Brassica maurorum (MM, 2n = 16) × B. juncea (AABB, 2n = 36) (M.AB), B. maurorum × B. carinata (BBCC, 2n = 34) (M.BC), and B. carinata × B. maurorum (BC.M), the three genomes of each hybrid were distinguished and autosyndesis and allosyndesis were evaluated. In M.AB, up to two autosyndetic bivalents occurred among the chromosomes of each genome; a maximum of three allosyndetic bivalents appeared between A-B, A-M, and B-M genomes. The similar pairings in M.BC and BC.M suggested that the cytoplasm of B. maurorum or B. carinata had no obvious effect on chromosome pairing. In M.BC and BC.M, a maximum of one autosyndetic bivalent was found for B and M genomes, but two were found for the C genome; from 0 to 2 allosyndetic bivalents were observed between B-C, B-M, and C-M genomes. The B-M allosyndesis frequency was higher than the A-M or C-M allosyndesis frequency in these hybrids, revealing the closer relationship of B and M genomes. The allosyndesis frequency was higher than the autosyndesis frequency among A, B, and C genomes in these combinations, suggesting that intergenomic homoeology was higher than intragenomic homoeology. The implications for genome evolution and crop breeding are discussed.
Publisher
Canadian Science Publishing
Subject
Genetics,Molecular Biology,General Medicine,Biotechnology