Draft

The expansion of the bread wheat gene pool can be achieved via the creation of synthetic hexaploid wheats (SHWs) and the backcrossing of these synthetics to elite breeding lines. Resistance to many biotic and abiotic stresses has been incorporated into new bread wheat cultivars using synthetic donors. Sufficient microsatellite markers (SSRs) were used to create a dense coverage of all the chromosomes to assess the genetic diversity present in synthetic hexaploid wheats, their backcross derived families, and their parents (where possible). SSRs were also used to test for the selective advantage of SHWs alleles in backcross families after several generations of selection. The SHWs investigated in this study had a high gene diversity and PIC for all SSRs, but highest for D genome markers. The SHWs clustered with their durum parents, but were clearly separated from bread wheat cultivars in a dendrogram. Gene diversity of the synthetic backcross derived lines (SBLs) for the A and B genomes was higher than that of their SHW and bread wheat parents. Gene diversity partitioned within each SBL family was extremely high. Principal coordinates analysis of the SBLs and their parents showed that lines from each SBL family clustered together and closer to their bread wheat parent than their SHW parent. De novo generation of genetic variation was seen in many of the SHWs, which was stably inherited in the SBL families. Non-Mendelian inheritance of alleles favoring the SHW parent was seen in some of the markers in one or more SBL families, suggesting that these genomic regions are being actively selected for.

Global Wheat Program

Text in English

0503|AL-Wheat Program

INT2692