To improve the seed purity management system of Korean wheat cultivars, 50 Korean wheat cultivars were subjected to chemical assays for grain color, genotyping of grain weight-related genes, and grain image analysis. The tested cultivars were primarily classified by NaOH and ninhydrin tests as white (26%) and red (74%) cultivars, as well as high PPO activity (48%), and low PPO activity (52%) cultivars, respectively. The allelic variations of Tamyb10 gene revealed Tamyb-A1a/Tamyb-B1a/Tamyb-D1a as the major allelic combination in white wheat and five different Tamyb10 genotypes (i.e., aba, abb, baa, bba, and bbb) in red wheat. Those cultivars with high PPO activity possessed the Ppo-A1a/Ppo-B1b/Ppo-D1b genotype, while those with low PPO activity possessed the Ppo-A1b/Ppo-B1a/Ppo-D1a genotype. In the grain image analysis, long grain cultivars displayed increased grain width, circularity, and area. Based on cluster analysis of grain traits, the Korean wheat cultivars were classified into two groups - 1) large red grain cultivars released before 2000, and 2) small red grain cultivars and white wheat cultivars released after 2000. Further research is required to determine the effects of grain filling conditions on the grain characteristics of Korean wheat cultivars and to develop efficient and reliable molecular markers for an improved seed purity management system.

This study aimed to develop an agarose gel-based multiplex PCR assay using sequence-tagged site (STS) and simple sequence repeat (SSR) markers that can differentiate Korean wheat cultivars. Forty-nine Korean wheat cultivars were primarily classified based on seed coat color into red (36) and white (13) groups. Red wheat cultivars were further differentiated by three multiplex PCRs using molecular markers for Ppo-A1/Vrn-D1a/Rht-B1b, Glu-A3ac/TaCwi-A1b/Lr34, and Glu-A1ac/Glu-B1b/KWSM003/TaSE96. Similarly, white wheat cultivars were further differentiated using two multiplex PCRs using the molecular markers for Ppo-A1/Vrn-D1a/Pina-D1a and Ppo-B1/Glu-B3h. A multiplex PCR assay using molecular markers for Glu-A1b/Glu-D1d/Wx-B1 was developed to differentiate four Korean wheat cultivars used as government certified seeds: Baekkang, Hwanggeumal, Keumkang, and Saekeumkang. A multiplex PCR assay using molecular markers for Glu-B3h and Pin-D1a was used for colored wheat cultivars, Arijinheuk, Ariheuk, and Chinese colored wheat. The multiplex PCR assays developed in this study can provide useful molecular tools for differentiating Korean wheat cultivars, developing wheat seed management systems, and guaranteeing wheat seeds in Korea.