The effect of softness genes on the biscuit-making quality of soft wheat

[摘要] English: The purpose of this study was firstly to determine the segregation ratios ofsoftness genes in this particular genetic background.* Secondly, the effect of these softness genes on bisquit-making quality hadto be determined.* A soft, white wheat cultivar was crossed with a hard red wheat cultivar.* The soft white wheat cultivar had the ability to produce biscuits with anacceptable diameter while the hard red wheat cultivar had agronomicqualities that rendered it suitable for production in the Northern Capeirrigation area of Southern Africa.* Soft wheat kernels were selected from the progeny using a microtome andmicron settings as an indication of kernel softness.* Micron settings were used as an indication of kernel softness. Soft texturedkernels had a setting of seven micron or higher. Hard textured kernels hada setting of between one and six micron.* The selected soft kernels were agronomically reconstructed to the hard redwheat cultivar for three generations, using the backcross method.Results showed that kernel softness is determined by a single locus and twoalleles, with the dominant gene determining kernel softness.The two near-isogenic lines that differed with regard to kernel texture, wereevaluated for milling and baking qualities.* The genes for kernel softness had no effect on dough strength as measuredby the mixogram.* The stability and dough strength as measured by the alveogram weresignificantly influenced by the genes for kernel softness. The AWRC wassignificantly lower in soft wheats.* The genes for kernel softness significantly increased biscuit diameter.* Break flour yield was highly correlated with biscuit diameter (r = 0.835),while the percentage flour protein (r = -0.797) and mixing time (r = -0.695)were significantly negatively correlated with biscuit diameter in the softgroup.* In the group with hard kernels, alveograph strength (r = -0.795) and AWRC(r = -0.713) showed a significantly negative correlation with biscuitdiameter.* The stepwise regression on biscuit diameter within the soft group showedhigh variances for flour extraction, break flour and alveograph strength.Within the hard group, high variances were found for flour protein, flourextraction, break flour and mixing time.

[发布机构] University of the Free State