| Polyphenol oxidase (PPO) activit and yellow pigment content are the importantcolor traits affecting the apparence of wheat-based products in wheat kernels.Polyphenol oxidase (PPO) is a major cause of time-dependent darkening anddiscoloration in Asian noodles and other wheat-based products. The highly yellowpigment content(YPC) will not only result in the flour yellowness increased, but alsoreduces the whiteness of the flour. They are both the main factors leading to the flourcolor and luster are not be fond of by Chinese consumers. Therefore, it is important tobreed new cultivars with white flour in the future quality breeding.In the present study, functional molecular marker were used to detect allelicvariants of polyphenol oxidase1(Ppo1) genes and phytoene synthase1(Psy1) genesin211historical cultivars and62spring wheat cultivars from China. Their PPOactivity and YPC were evaluated to associate with genetypes. The main resultsobtained in this study are summarized below.1. In the211tested materials, The results showed that the frequencies of allelicvariations Ppo-A1b, Ppo-B1a and Ppo-D1b were69.19%,69.19%and63.51%,respectively. The frequencies of allelic combinations Ppo-A1a/Ppo-B1a/Ppo-D1b,Ppo-A1a/Ppo-B1b/Ppo-D1b,Ppo-A1b/Ppo-B1a/Ppo-D1a,Ppo-A1b/Ppo-B1b/Ppo-D1a,Ppo-A1a/Ppo-B1a/Ppo-D1a,Ppo-A1a/Ppo-B1b/Ppo-D1a,Ppo-A1b/Ppo-B1a/Ppo-D1band Ppo-A1b/Ppo-B1b/Ppo-D1b were10.53%,2.92%,16.96%,9.36%,7.02%,2.34%,40.35%and10.53%, respectively. The mean PPO activity of the wheat with theseallelic combinations were43.94A475/(min·g·103),43.81A475/(min·g·103),15.62A475/(min·g·103),15.83A475/(min·g·103),38.00A475/(min·g·103),34.24A475/(min·g·103),32.63A475/(min·g·103) and10.53A475/(min·g·103), respectively. Andthe range of the PPO activity were from34.64to57.34A475/(min·g·103), from33.38to56.65A475/(min·g·103), from10.25to25.00A475/(min·g·103), from9.35to26.64 A475/(min·g·103), from26.05to48.03A475/(min·g·103), from31.78to38.46A475/(min·g·103), from9.24to57.34A475/(min·g·103) and from22.63to44.10A475/(min·g·103), respectively. Among these allelic combinations,Ppo-A1a/Ppo-B1a/Ppo-D1b and Ppo-A1a/Ppo-B1b/Ppo-D1b are associated with highPPO activity. Ppo-A1b/Ppo-B1a/Ppo-D1a and Ppo-A1b/Ppo-B1b/Ppo-D1a areassociated with low PPO activity. The other four allelic combinations are associatedwith middle PPO activity. Generally, the number of cultivars with middle PPOactivity in wheat historical wheat was high. The markers PPO18, PPO16and PPO29can efficiently help for wheat quality improvement and molecular breeding when theywere used cooperatively. The function of molecular F-8need to be further studied.2. In the62tested spring spring wheat varieties, The results showed that thefrequencies of allelic variations Psy-A1a and Psy-A1b at Psy-A1loci in thesecultivars(lines) were64.52%and35.48%, respectively. But Psy-A1c allele was notfound. Four alleles Psy-B1a, Psy-B1b, Psy-B1c and Psy-B1d at Psy-B1locus werefound, and the proportion of these were54.84%,38.71%,4.84%and1.61%,respectively. But Psy-B1e allele was absent in these cultivars(lines). There was onlyallele Psy-D1a be found except Moyin1. The frequencies of allelic combinationsPsy-A1a/Psy-B1a/Psy-D1a, Psy-A1a/Psy-B1b/Psy-D1a, Psy-A1b/Psy-B1a/Psy-D1a,Psy-A1b/Psy-B1b/Psy-D1a, Psy-A1a/Psy-B1c/Psy-D1a, Psy-A1a/Psy-B1d/Psy-D1aand Psy-A1b/Psy-B1c/Psy-D1a were33.87%,25.81%,20.97%,12.90%,3.23%,1.61%and1.61%, respectively. The mean yellow pigment content of the cultivarswith these allelic combinations were4.44mg·kg-1,4.21mg·kg-1,4.44mg·kg-1,3.83mg·kg-1,5.51mg·kg-1,4.33mg·kg-1and4.26mg·kg-1, respectively. The range of theyellow pigment content for the first four allelic combinations were from3.09to6.92mg·kg-1, from2.92to6.40mg·kg-1, from2.47to9.11mg·kg-1, from2.98to5.13mg·kg-1, from5.13to5.89mg·kg-1, respectively. Psy-A1b/Psy-B1d/Psy-D1a alleliccombinations was absent in these varieties. Among of these allelic combinationsPsy-A1b/Psy-B1b/Psy-D1a, Psy-A1a/Psy-B1c/Psy-D1a correlate with high and lowyellow pigment content, respectively. Generally, the number of cultivars with middleyellow pigment content in spring wheat was high. The markers were used in thisstudy can efficiently help for wheat quality improvement and molecular breedingwhen they were used cooperatively. |
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