Meiotic disturbances in F1 hybrids and their progenies are still major problems in wide hybridization.To investigate the genome affinity reflected in chromosome pairing and segregation,we studied chromosome behaviors ...Meiotic disturbances in F1 hybrids and their progenies are still major problems in wide hybridization.To investigate the genome affinity reflected in chromosome pairing and segregation,we studied chromosome behaviors during meiosis in two interspecific F1 hybrids[O.minuta×O.australiensis(Om×Oa,BCE genome)and Oa×O.ridleyi(Or,EHJ genome)]by using both traditional staining methods and genomic in situ hybridization(GISH).GISH analysis has been successfully performed on mitotic chromosomes to distinguish different Oryza genomes,but relatively fewer systematic analyses of meiotic chromosomes of interspecific hybrids have been reported.In the hybrids,highly irregular chromosome behaviors through meiosis resulted in producing microspores with unbalanced genome.At diakinesis of these two hybrids,most chromosomes present as univalent,with low frequency as bivalents and occasionally as trivalents.In a pollen mother cell,2 to 8 bivalents and 0 to 4 trivalents were observed in the hybrid Oa×Or,and 1 to 8 bivalents and 0 to 5 trivalents were observed in the hybrid Om×Oa.GISH results indicated that 51.52%bivalents in Oa×Or and 79.65%bivalents in Om×Oa involved allosyndetic association,which indicates that recombination and introgression should be possible if viable backcrosses can be recovered even from triploid hybrids.In this study,we revealed that the meiotic disturbance due to low affinities between parental genomes is the major reason for the sterility of these two triploid interspecific hybrids.The two hybrids showing vigor in reproductive growth are potential genetic resources in future breeding programs.A better understanding of genomic affinities between these distant Oryza species can facilitate planning an effective breeding program by using wide hybridization,and efficient and routine GISH analysis is helpful to monitor alien introgression in the process.展开更多
Since the middle of 1980’s, wide compatibility(WC) rice lines have been screened by ricebreeders in China and applied in hybrid ricebreeding program. Several WC lines such asPecos, T984, Lunhui 422, and 02428 withide...Since the middle of 1980’s, wide compatibility(WC) rice lines have been screened by ricebreeders in China and applied in hybrid ricebreeding program. Several WC lines such asPecos, T984, Lunhui 422, and 02428 withideal agronomic characters were identified. Weincorporated the WC gene into restorer linesby crossing these japonica WC lines with ob-tained indica lines. Some WC restorer lineswith indica-japonica medium type were ob-tained and their application value in intersub-specific hybrid rice breeding were evaluated. 1. Effect of crossing methods on selectionefficiencies of WC restorer lines展开更多
RAPD and RFLP analyses of double haploid lines which derived from hybridization between hexaploid wheat (Triticum aestivum L. 2n=42) and eastern gamagrass (Tripsacum dactyloides L. 2n=4x=72) are reported. Two of the 3...RAPD and RFLP analyses of double haploid lines which derived from hybridization between hexaploid wheat (Triticum aestivum L. 2n=42) and eastern gamagrass (Tripsacum dactyloides L. 2n=4x=72) are reported. Two of the 340 Operon primers have been screened, which stably amplified Tripsacum dactyloides (male parent) specific bands in the double haploid lines. These results confirm the fact that Tripsacum dactyloides DNA has been integrated into wheat genome by sexual hybridization at molecular level. This idea has been further testified by RFLP analysis. Application and potentials of transferring Tripsacum dactyloides DNA into wheat genome by sexual hybridization in wheat breeding are discussed.展开更多
基金the Institute of Plant and Microbial Biology,Academia Sinica,and Ministry of Science and Technology,Taiwan,China(Grant No.MOST103-2313-B-001-001)。
文摘Meiotic disturbances in F1 hybrids and their progenies are still major problems in wide hybridization.To investigate the genome affinity reflected in chromosome pairing and segregation,we studied chromosome behaviors during meiosis in two interspecific F1 hybrids[O.minuta×O.australiensis(Om×Oa,BCE genome)and Oa×O.ridleyi(Or,EHJ genome)]by using both traditional staining methods and genomic in situ hybridization(GISH).GISH analysis has been successfully performed on mitotic chromosomes to distinguish different Oryza genomes,but relatively fewer systematic analyses of meiotic chromosomes of interspecific hybrids have been reported.In the hybrids,highly irregular chromosome behaviors through meiosis resulted in producing microspores with unbalanced genome.At diakinesis of these two hybrids,most chromosomes present as univalent,with low frequency as bivalents and occasionally as trivalents.In a pollen mother cell,2 to 8 bivalents and 0 to 4 trivalents were observed in the hybrid Oa×Or,and 1 to 8 bivalents and 0 to 5 trivalents were observed in the hybrid Om×Oa.GISH results indicated that 51.52%bivalents in Oa×Or and 79.65%bivalents in Om×Oa involved allosyndetic association,which indicates that recombination and introgression should be possible if viable backcrosses can be recovered even from triploid hybrids.In this study,we revealed that the meiotic disturbance due to low affinities between parental genomes is the major reason for the sterility of these two triploid interspecific hybrids.The two hybrids showing vigor in reproductive growth are potential genetic resources in future breeding programs.A better understanding of genomic affinities between these distant Oryza species can facilitate planning an effective breeding program by using wide hybridization,and efficient and routine GISH analysis is helpful to monitor alien introgression in the process.
文摘Since the middle of 1980’s, wide compatibility(WC) rice lines have been screened by ricebreeders in China and applied in hybrid ricebreeding program. Several WC lines such asPecos, T984, Lunhui 422, and 02428 withideal agronomic characters were identified. Weincorporated the WC gene into restorer linesby crossing these japonica WC lines with ob-tained indica lines. Some WC restorer lineswith indica-japonica medium type were ob-tained and their application value in intersub-specific hybrid rice breeding were evaluated. 1. Effect of crossing methods on selectionefficiencies of WC restorer lines
文摘RAPD and RFLP analyses of double haploid lines which derived from hybridization between hexaploid wheat (Triticum aestivum L. 2n=42) and eastern gamagrass (Tripsacum dactyloides L. 2n=4x=72) are reported. Two of the 340 Operon primers have been screened, which stably amplified Tripsacum dactyloides (male parent) specific bands in the double haploid lines. These results confirm the fact that Tripsacum dactyloides DNA has been integrated into wheat genome by sexual hybridization at molecular level. This idea has been further testified by RFLP analysis. Application and potentials of transferring Tripsacum dactyloides DNA into wheat genome by sexual hybridization in wheat breeding are discussed.
