IDENTIFICATION OF INTROGRESSED CHROMOSOMESEGMENTS OF DURUM WHEAT IN A HIGH GRAIN WEIGHT INTROGRESSION LINE OF BREAD WHEAT cv. PBW343 THROUGH GRAPHICAL GENOTYPE ANALYSIS

摘要

Present study provides a graphical account of introgression of chromosomal regions of durum wheat into bread wheat achievable just in two back crosses. Bread wheat cv. PBW343 was crossed with a durum wheat line DWR1006 and the Fl was backcrossed two times with cv. PBW343. In the BC, generation an interesting hexaploid wheat line PBW343/DWR1006 was isolated that had higher grain weight than the grain weight of both its parental genotypes. The graphical genotype analysis was carried out of an introgressed line of hexaploid wheat line PBW343/DWR1006 that has high grain weight with a view to determine the chromosomal regions inherited from the hexaploid and durum wheat parental genotypes. For this purpose, a set of445 SSRs mapped on different chromosomes of A and B sub-genomes of wheat were tried. Out of 445 SSRs, 276 SSRs showed polymorphism between the hexploid bread wheat cv. PBW343 and the tetraploid durum wheat line DWR 1006, the two parental genotypes of the hexploid introgressed line PBW343/DWR1006 and the 276 polymorphic SSRs were utilized for graphical genotype analysis of the introgressed hexaploid line PB W343/DWR1006. The number of polymorphic SSRs mapped on each of the 14 chromosomes of A and B sub-genomes varied from 11 (chromosome 4B) to 25 (chromosome 2A). It may be noted that each of the 14 A and B sub-genomes chromosomes had variable proportions of the genomic regions inherited from the hexaploid bread and tetraploid durum wheat. Each of the three chromosomes 1 A, 2B and 5B had equal proportion (50%) of genome each from the hexaploid bread and tetraploid durum wheat. The chromosomes IB and 7A had relatively large shares of regions from the hexaploid bread wheat than the tetraploid durum wheat. Each of the remaining nine chromosomeshad as much as 53.84% (chromosome 3B) to 78.26% (chromosome 6B) regions from the durum wheat parental genotype DWR 1006. As expected the overall chromosomal regions contributed by the durum wheat was higher (56.80%) than the regions contributed by the hexaploid wheat (43.17%).