Genotypic Variation And Environmental Effects On Antioxidantproperties In Sweetpotatoes

With the growth of people's health awareness, more and more attention has been given to sweetpotato as a nutritional and healthcare food resource. Antioxidant property is one of the most important sweetpotato functions for our health, and therefore become a main research priority for sweetpotato. A multiple location experiments of 21 genotypies and 5 growing locations with three duplications were conducted in this paper. Two antioxidant compositions, polyphenol and flavonoid, and antioxidant activity for all samples tested were determined by the UV-spectrophotometer method, the genotype variation and environmental effects on the antioxidant compositions and antioxidant activity of sweetpotato storage roots were analysied, the correlations among antioxidant compositions, antioxidant activity and other major qulatity characters were also analysised. The main results are as followed:1. The optimal extrational conditions, including ethanol 60%, extracting time 88 minutes, the ratio of sample to extracting reagent 1: 60, were obtained by using response surface method.2. The polyphenol contents of sweetpotato samples from the multiple location experiments were determined, genotypes, locations and genotype by location interaction were found to have extremely significant effects on polyphenol content in sweetpotato. After a comprehensive assessment and stable analysis, some genotypes with high polyphenol contents, such as "Zheda9201", Xu55-2", "Jinshan1222", "Zhe34-81" and "Xu55-2", were identified and can be used as parents for high polyphenol content breeding.3. The flavonoid contents of sweetpotato samples from the multiple location experiments were determined; genotype, location and genotype by location interaction were found to have extremely significant effects on flavonoid content in sweetpotato. After a comprehensive assessment and stable analysis, some genotypes with high flavonoid contents, such as "Zheda9201", "Beijing553", "Jinshan1222", "Zhe255", were identified and can be used as parents for high flavonoid content breeding.4. The antioxidant activities of sweetpotato samples taken from the multiple location experiments were determined; genotype, location and genotype by location interaction were found to have extremely significant effects on antioxidant activities in sweetpotato. After a comprehensive assessment and stable analysis, some genotypes with high antioxidant activity, such as "Yi306", "Zheda9201", "Zhe45-47", "Zhe34-81", and "Zhe7528", were identified and can be used as parents for high antioxidant activity breeding.5. After a comprehensive assessment of antioxidant properties for all sweetpotato genotypes tested, the purple flesh clone "Zheda9201" was found to have high polyphenol content, high flavonoid content and strong antioxidant activity, This result indicated that purple flesh sweetpotato had special antioxidant function.6. The results of correlation analysis showed that the polyphenol content and flavonoid content had extremely positively significant correlations with antioxidant activity. The polyphenol content has extremely positively significant correlations with flavonoid content. The polyphenol content and flavonoid content have extremely negatively significant correlations with starch content, and have no significant correlations with soluble sugar and general acceptability. Antioxidant activity has positively significant correlation with starch content, and no significant correlations with soluble sugar and general acceptability. Browning degree has positively significant correlations with polyphenol content, but has no significant correlations with flavonoid content and antioxidant activity.The present research results provided a theoretical base for functional sweetpotato breeding and cultivation.