Effect of HMWGs subunits on SDS sedimentation test volume in inbred breeding lines generated from the cross Buck Poncho / Baguette 10

TERRILE I.; VANZETTI L.; HELGUERA M.

Rosario. Argentina

Congreso; 1º Conferencia Latinoamericana ICC; 2007

Wheat seed storage proteins play a important role in to the determination of dough and bread-making quality. Glutenins are polymeric proteins whose subunits are classified into two groups, high molecular weight (HMWGs, 80-120 kDa) and low molecular weight (LMWGs 30-50 kDa) subunits. The HMWG subunits are controlled by the Glu-A1, Glu-B1, and Glu-D1 genes, on the long arms of chromosome 1A, 1B, and 1D. Bread-making quality can be determined by several biochemical tests, one of the most used is the SDS sedimentation test, in which higher SDS volume values are associated to better bread-making quality. The aim of this study was to determine the effect of different HMWG subunit combinations on the SDS sedimentation volume in hexaploid wheat. In the study, 583 F5 inbred lines originated from the cross Buck Poncho x Baguette 10 were evaluated by SDS sedimentation test. Buck Poncho is a cultivar with an excellent bread-making quality and a HMWGs subunits composition of Glu-A1: 2*; Glu-B1: 7oe+8; Glu-D1: 5+10; Baguette 10 is a cultivar with poor bread-making quality and a HMWGs subunits composition of Glu-A1: null; Glu-B1: 6+8; Glu-D1: 5+10. A subgroup of 16 F5 lines with the lowest SDS volume (28 to 34 cm3) and 23 F5 lines with the highest SDS volume (54.5 to 61.5 cm3) were selected to elucidate the effect of different HMWGs subunits combinations and SDS sedimentation volumen. F5 lines with heterozygous 6-7oe+8 HMWG subunit composition were discarded of the analysis and F5 lines scored as 2* can be homozygous 2* or heterozygous 2*-null. In this subgroup, the HMWGs composition explained 89% of the variability observed in the SDS sedimentation test. The Glu-A1 locus showed a highly significant effect on SDS volume (P < 0.0001) 2* > null. Glu-B1 locus also presented a highly significant effect on SDS volume (P < 0.0001) 7oe+8>6+8. The interaction of Glu-A1*Glu-B1 showed a highly significant effect on SDS volume (P < 0.0001) null/7oe+8=2*/7oe+8>2*/6+8>null/6+8. All this data support the use of Buck Poncho HMWGs subunits to rapidly improve bread wheat quality in breeding programs. Nevertheless, further studies discriminating lines carrying 2* or 2*-null subunits will provide a even better picture of the effect of the HMWGs subunits in this population on bread-making quality.