The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytoplasmic proteins in the cultivars used. The high yield but low protein cultivar showed a consistent decline of protein content during grain filling but the high - protein cultivars increased their psotein contant after 25 days post-anthcsis. The accumulation of storage proteins was different from that of cytoplasmic protein, and there were also cultivar variations. However, all cultivars reached their, maximum-synthesizing capacity for storage proteins at maturity. The relationship between the protein fractions or their ratio and baking quality was also discussed. The accumulation of protein fractions was analyzed on developing and mature wheat grains of three cultivars differing in protein content and baking quality. There was a slight difference in the accumulation of cytoplasmic proteins in the cultivars used. The high yield but low protein cultivar showed a consistent decline of protein content during grain filling but the high - protein cultivars increased their psotein contant after 25 days post-anthcsis. The accumulation of storage proteins was different from that of cytoplasmic protein, and there were also cultivar variations. However, all cultivars reached their , maximum-synthesizing capacity for storage proteins at maturity. The relationship between the protein fractions or their ratio and baking quality was also discussed.