Allelic Variation of the Polyphenol Oxidase Gene in Henan Winter Wheat

In order to characterize the genotype and phenotype of polyphenol oxidase(PPO) in Henan wheat,a total of 72 Henan wheat new lines were used to examine kernel PPO activity,and were also genotyped by the functional markers PPO18,PPO16 and PPO29 for the identification of four allelic variants Ppo-A1a,Ppo-A1b,Ppo-D1a and Ppo-D1b on chromosomes 2A and 2D.The results indicated that the frequencies of Ppo-A1a genotype with high PPO activity and Ppo-A1bgenotype with 1ow PPO activity at Ppo-A1 locus were 72.2% and 27.8%,respectively,and Ppo-D1a genotype with 1ow PPO activity and Ppo-D1with high PPO activity at Ppo-D1b locus were 70.8% and 29.2%,respectively.There were four allelic combinations of PPO genes identified of Ppo-A1a/ Ppo-D1a(50.0%),Ppo-A1a/ Ppo-D1(22.2%),Ppo-A1b/ Ppo-D1a(20.8%) and Ppo-A1b/ Ppo-D1(7.0%).Further analyzing the effect of different allelic combination on PPO activity showed that in the four different genotypes Ppo-A1b/ Ppo-D1a had lowest PPO activity.This study indicated that wheat new lines with the low PPO activity had relatively lower frequency in Henan province.Therefore,screening materials with relatively low PPO activity should be one of the important objectives for wheat quality improvement in Henan province in the future.