분자표지 이용 Polyphenol Oxidase 저활성 국산밀 유전자원 선발

Selection of Korean Wheat Germplasms with Low Polyphenol Oxidase using Polyphenol Oxidase-Specific DNA Markers

The color of wheat flour and dough affect significantly on the quality of wheat. The major factor causing darkening of dough color is activity of polyphenol oxidase (PPO). Therefore, we examined the relationship between the PPO activities and the genotypes of the PPO-specific molecular markers in Korean wheat cultivars, and tested the usefulness of the selected markers for the selection of Korean wheat germplasm lines low in PPO activity. Five sequence-tagged site (STS) markers specific to wheat PPO genes, PPO-05, PPO-16, PPO-18, PPO-30 and PPO-43, were examined for their levels of polymorphism in Korean wheat cultivars. The genotypes of the marker PPO-18, which is linked to Ppo-A1 locus, were correlated significantly highly with the levels of grain PPO activity. Furthermore, Korean wheat cultivars could be classified into the high or low PPO activity group by the allele type of Ppo-A1 which was differentiated by the PPO-18. Grain PPO activity was lower about twice in the cultivars with Ppo-A1b allele than in those with Ppo-A1a allele. The cultivars with Ppo-A1b allele had lower grain weight and wide grain width, also they had less ash, protein, Fe and total polyphenol than those with Ppo-A1a allele. Thus, the lightness of flour and dough sheet was brighter in the cultivars with Ppo-A1b allele. The four wheat cultivars including Suwon252, which had lowest PPO activity and Ppo-A1b allele, were selected from 200 genetic lines as valuable genetic resources for the breeding of wheat variety with bright white-colored flour.