| Stable isotope fingerprint technique is one of the effective techniques for Agro-product geographical traceability.The fingerprint information of stable isotope is not only affected by the factor of region,but also has the potential to be affected by genotype,harvest year and the interactions,whether the isotopic variation of wheat milling products and components among different regions and genotypes is consistent with wholemeal is still uncertain.However,these questions will influence the reliability of the result of geographical traceability.Huixian?Henan province?,Yangling?Shaanxi province?and Zhaoxian?Hebei province?were chosen as the experiment sites in our study,a 5-year continuous field experiment was conducted with 10genotypes of wheat.The provenance soil,groundwater,rainfall and wheat kernel were collected,and the wheat samples were further milled and extracted to obtain the wheat milling products?bran,shorts and white flour?and different components?crude fat,defatted flour,gluten,starch and crude fiber?.The element analysis-isotopic ratio mass spectrometry?EA-IRMS?and thermal ionization mass spectrometer?TIMS?were used to determine the light stable isotopes(?13C,?15N,?2H)and 87Sr/86Sr,respectively.Combined with the chemometrics method,the stable isotopes of?13C,?15N,?2H and87Sr/86Sr were tested whether there existed significant differences among different regions,genotypes and harvest years,the effects and variance contribution rates of region,genotype,harvest year and their interactions were assessed for each isotope.The relationship for?2H between wheat and soil water with different growth stages and different depths and for 87Sr/86Sr between wheat and soil?both bulk and bio-available Sr?at different depths were analyzed,and the trend among three regions for?2H and87Sr/86Sr of rainfall,groundwater and soil with respective wheat were compared.The relationships between different wheat milling products,components and wholemeal for?13C,?15N and?2H were analyzed.Furthermore,the effects and the variance contribution rates of region,genotype and their interaction for?13C,?15N and?2H of each milling product and component were also validated.The classification results of stable isotopes in wheat kernel and components for wheat geographical origin were compared,and effective indicators were selected for identifying the geographical origin of wheat.The main conclusions were as follows:1.The?13C in wheat kernel was significantly affected by region,genotype,harvest year and their interactions,region contributed most for its variation,?13C can be used for identifying the geographical origin of wheat kernel,milling fractions,gluten,starch and crude fiber.2.The?15N in wheat kernel was significantly affected by region,genotype,harvest year and their interactions,region contributed most for its variation,and no significant difference was observed for?15N among wheat kernel and milling fractions,?15N can be used for identifying the geographical origin of wheat kernel,milling fractions,gluten and crude fiber.3.The?2H in wheat kernel was significantly affected by region,genotype,harvest year and region× harvest year,region contributed most for its variation,?2H can be used for identifying the geographical origin of wheat kernel,milling fractions,gluten and crude fiber.4.The 87Sr/86Sr in wheat kernel was significantly affected by region and harvest year,region contributed most for its variation,87Sr/86Sr can be used for identifying the geographical origin of wheat kernel.5.The?2H in wheat kernel mainly comes from rainwater and soil water,and was seldom affected by groundwater,while the 87Sr/86Sr in wheat kernel mainly comes from soil and groundwater,and was seldom affected by rainwater.6.The combination of light stable isotopes(?13C,?15N and?2H)and 87Sr/86Sr can enhance the correctclassification rate for wheat geographical origin,?15Nwholemeal,?2Hwholemeal,?13Cgluten,?13Cflour,?13Cwholemeal and?13Cbran were more suitable for identifying the geographical origin of wheat. |
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