Impact of introducing alien storage proteins on the bread-making quality and agronomic performance of spring wheat
The relatively narrow genetic base of spring wheat grown in western Canada puts the crop at risk from attack by pests which reduce yield and marketability. Interspecific hybridization is used to introduce new genetic sources of resistance to wheat pests. This study was conducted in order to evaluate the effectiveness of endosperm protein fingerprinting in selecting backcross-derived (BC) lines from the cross Park*3/ T. timopheevi. SDS-PAGE and A-PAGE were used to identify the high molecular weight (HMW) glutenin subunit and gliadin constitution, respectively, of the BC lines. Although no exotic HMW glutenin subunits were present in the BC lines, a high frequency lacked the 'A' genome subunit. This 'null' condition was deleterious to bread-making quality. The BC lines with the null condition were characterized by the transfer of novel omega and gamma gliadin proteins from T. timopheevi and kernel texture normally associated with tetraploid wheat. Despite the level of back-crossing, a large majority of the lines were inferior to the recurrent parent for agronomic performance. Delayed heading, resulting from the putative transfer of a major maturity gene from T. timopheevi, was associated with low grain yield in 1991 but higher yield in 1992. Lines with improved baking quality tended to be low-yielding. Based on this study, protein fingerprinting can be used to select interspecific lines with desirable end-use quality.
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