The white salted noodle-making quality of wheat cultivars in the western region of Japan is lower than that of Australia standard white, because the dough physical property, which is related to the noodle-making process, is weak in these cultivars. Most of the wheat cultivars in this area exhibit a null allele at the Glu-A1 locus, subunits 7+8 at the Glu-B1 locus and subunits 2+12 or 2.2+12 at the Glu-D1 locus. The effect of these high-molecular-weight glutenin subunits (HMW-GS) on the dough physical property was studied using eight kinds of near-iso-genic lines. NILs with a null allele at the Glu-A1 locus and 2.2+12 subunits at the Glu-D1 locus contained a significantly low level of unextractable polymeric protein (UPP) and showed a weak dough physical property compared with the NILs with subunits 1 and 2.2+12. In particular, NILs composed of HMW-GS with the null allele, 7+8 and 2.2+12 subunits showed the lowest values of UPP and physical property. On the other hand, the null allele at Glu-A1 exerted a small effect on the UPP level and the physical property in the NILs with 2+12 subunits at the Glu-D1 locus. Based on these results, it was conclude that the interaction between the Glu-A1 and Glu-D1 loci affected the dough physical property. Although the HMW-GS alleles have generally been identified by SDS-PAGE analysis, it is difficult to detect the allele at Glu-A1 in HMW-GS with a certain composition. Accordingly, we developed allele-specific PCR markers to detect the subunits 1, 2^* and null allele at the Glu-A1 locus.

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Characters related to the pearling quality of four six-row barley varieties Shunrai, Fibersnow, Silkysnow and Minorimugi, which were developed for pearling use at Nagano Prefecture Agricultural Experiment Station, were investigated during the period from 2002 to 2006. 1000-grain weight, steely-grain rate, grain-thickness distribution, furrow-width rate of 55% pearled grains, pearling time, 55% pearled grain whiteness, perfect-pearl-grain rate after 55% pearling, ratio of broken kernels after 55% pearling and 30% pearled grain flour paste color were analyzed. Steely-grain rate, grain-thickness distribution and furrow width were highly correlated to the pearled grain whiteness. The higher distribution of 2.6 mm or thicker grains, the lower furrow width of pearled grains and the lower steely-grain rate, respectively, were related to the higher pearled grain whiteness. Multiple regression analysis indicated that these three factors controlled about 80% of pearled grain whiteness. The grain thickness contributed most to the whiteness. Furrow width affected whiteness more than the steely-grain rate. The varietal differences in these three traits were considered to be significant. The values of the heritability estimates of grain-thickness distribution, furrow width of pearled grains and steely-grain rate were 0.71, 0.62 and 0.56, respectively. However, varietal differences in pearled grain whiteness were statistically not significant and the value of the heritability estimate was 0.26. Therefore, screening only based on pearled grain whiteness was not effective to select whiter pearled grains. More emphasis should be placed on the selection of grain thickness, furrow width of pearled grains and steely-grain rate, and each factor should be modified independently to develop barley varieties with whiter pearled grains.

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