Gene Stacking of High Molecular Weight Glutenin Genes In Bread Wheat Using Molecular Markers.

Bread quality is one of the important characteristics that wheat breeders aim to improve by crossing and selection. Glutenins are key factors in improving bread quality and especially HMW-GS as they are the most contributors to bread quallity. This study aimed to screen fourteen local (growm in Saudi arabia) and international wheat varieties for their content of high molecular weight glutenin genes (HMW-GS) using nine specific primers for HMW-GS by PCR (Polymerase Chain Reaction). Fourteen wheat varieties of different origins (four varieties from CYMMIT; Irena, Tia, Kauz and Parus, three American varieties; Bonus, Klasic and Yecora rojo, three Australian varieties; Lang, Giles and Drysdale and four local lines; KSU 102,  KSU 103, KSU 105  and KSU 106)  were screened using nine specific primers for HMW-GS. The results showed that American varieties had the highest average quality score, followed by the Australian ones, local varieties, and the CYMMIT varieties according to a new scoring program that calculates the quality score for each wheat variety. Yecora rojo with composition (Ax1/Bx17+By18/Dx5+Dy10) and Lang (Ax1/Bx7*+By8/Dx2+Dy12) were chosen to the crossing program in November 2007 in educational farm of College of Food and Agricultural Sciences, King Saud University, Riyadh. The two parents were crossed together in order to stack favorable alleles in one genotype, then F1 seeds were harvested and planted in May 2008 in growth chamber to do selfing to get the segregations in the F2 plants which were planted separately in November 2008 and screened for HMW-GS to select homozygous favorable combinations. Results of F2 screening showed all expected segregations among which was the genotype (Ax1/Bx7*+By8/Dx5+Dy10) which had a quality score of 12 which is better than its two parents Yecora rojo and Lang, their quality score being 11 and 9 respectively. This new favorable homozygous combination represents about 6% of the F2 population and it was selected to undergo more future studies in order to determine its agronomic traits.