| Sweetpotato [Ipomoea batatas(L.)Lam.] storage roots have a broad market prospects of eating consumption and food processing,except for because of multiple nutrient substance in their storage roots,more because their high contents of polyphenol,flavonoid,chlorogenic acid,carotene and other active ingredients with antioxidant physiological action.Nine edible sweetpotato varieties planted at Yushan,Shaoqing and Shiliu towns in Pengshui county,Chongqing were conveyed on the length,width,weight,chromatic value,eating taste,contents of dry matter,polyphenol,total flavonoid,chlorogenic acid of fresh storage roots sampled on 65 d,95 d,125 d and 155 d after transplanting and 10 mineral elements and crude protein of storage roots at 155 d.The difference of the variation characteristics about agronomic traits,nutrient contents and eating taste qualities of storage roots among growth periods and sites in varieties were analyzed,and the quality factor of nutrient and eating tastes of storage roots were excavated by the principal component analysis and membership function analysis methods,in order to discriminate edible variety categories and their characteristics,and to provides some references for high quality edible sweetpotato varieties breeding.The main results are as follows:1.The three-way ANOVA of varieties,sites and growth periods showed that varieties,sites and growth periods had significant or extremely significant effects on sweetpotato storage roots traits,and the interaction effects between the three factors and most pairwise factors were significant or extremely significant.The F values of three factors shown that varieties had more great effects on fresh storage root number of per plant,all flesh chromatic values,the flesh color and moisture indexes of eating tastes and that the width,length-width ratio of storage roots,fresh storage root weight per plant,fresh weight per root,weights and percents of commercializable root per plant,weights of eating storage root per plant,the fragrance and sweetness indexes of eating tastes,and the contents of polyphenols,total flavonoids and chlorogenic acid in storage roots were more greatly affected by the growth periods,and the contents of dry matter,the powderiness and viscosity indexes of eating tastes were greatly affected by the varieties by growth periods interaction,and that the sites bygrowth periods interaction had great effects on the length and percents of eating root per plant in sweetpotato.2.During the growth period,the width of storage roots was significantly enlarged while the length-width ratio of storage roots was significantly decreased.Meanwhile,the fresh storage root weight per plant,fresh weight per root and weights of commercializable root per plant increased significantly,and the storage root number of per plant was stable.The length of storage roots of Zhongshu No.1,Qinshu No.5,Guangshu 87 and Yanshu 25 reached stabilization at 95 d,and the other five varieties reached stabilization at 125 d.The percents of commercializable root per plant of six varieties other than Zhongshu No.1,Longshu No.9and Jishu 26 will not increase after 125 d.The percents eating roots per plant in Longshu No.9 and Wanshu No.7 exceeded 45% at 65 d,and reached the highest at 95 d,followed by a significant decline.After 95 d,the percents eating root per plant in Zhongshu No.1 and Shangshu 19 reached a stable level,while that of the other five varieties did not significantly increase after 125 d.The weighs eating root per plant in Zhongshu No.1,Qinshu No.5,Guangshu 87 and Yanshu 25 has been increasing significantly during growth periods while the other five varieties no longer significantly increased after 125 d.The weights and percents of processable root per plant of Longshu No.9 and Wanshu No.7 was significantly increased after 95 d,and Zhongshu No.1,Shangshu 19,Wanshu No.10 and Jishu 26 increased significantly after 125 d,while the weights and percents of processable root per plant of Qinshu No.5,Guangshu 87 and Yanshu 25 have been low during the growth periods.Correlation analysis at variety level between the storage root traits showed,the width of storage roots was significantly positively correlated with the storage root number per plant and weights and percents of commercializable root per plant.At the early growth periods,the width of storage roots was significantly positively correlated with the weights of eating storage root per plant,and at the later growth periods,the width of storage roots was extremely positively correlated with weights of processable root per plant,but negatively correlated with the percents of eating root per plant.3.The flesh chromatic value analysis of fresh storage roots showed that the variation of a* value between varieties and growth periods larger than other chroma value indexes,and the membership function evaluation of eating qualities of steamed storage roots in Wanshu No.7,Yanshu 25 and Wanshu No.10 had relatively good taste.Each growth period,the dry matter content of storage roots in Zhongshu No.1 and Qinshu No.5 were relatively high,and Longshu No.9 was the lowest.The dry matter content of storage roots in all varieties showed that the variation trend of dry matter contents increased from 65 d to 95 d,decreased from 95 d to 125 d,and increased again from 125 d to 155 d,and storage root had the highest of dry matter contents at 95 d.4.The polyphenol contents were from 66.17 to 256.32 mg/100 g,and the total flavonoid contents were from 72.44 to 538.58 mg/100 g,and the chlorogenic acid contents were from33.04 to 178.87 mg/100 g in fresh storage roots of nine varieties,three sites and four growth periods.The polyphenol,total flavonoid and chlorogenic acid contents in fresh storage roots of Wanshu No.10,Qinshu No.5 and Guangshu 87 were relatively high among nine varieties.The polyphenol contents fluctuated up and down during the growth period(except Longshu No.9 and Qinshu No.5 showed continuous increase),and the total flavonoid and chlorogenic acid contents showed an increasing trend.Correlation analysis during growth periods showed that 95 d-125 d was the key period for the accumulation of the polyphenol,total flavonoid and chlorogenic acid contents in fresh storage roots of nine varieties.5.There were significant differences in the contents of mineral elements and crude proteins among the varieties at 155 d,among which the contents of crude protein,Ca,Fe,Cu and Zn were the highest in Zhongshu No.1,and the contents of P,K,Mg and B were the highest in Qinshu No.5,and the Se contents were the highest in Shangshu 19.The contents of most mineral elements and crude protein in fresh storage roots were the lowest or lower in Longshu No.9.6.The principal component analysis of various indexes showed that the flesh chroma value were reduced to a independent principal component,and the feature vectors of the a*and C value were the largest.Taste of steamed storage roots were reduced to two independent principal components,the feature vectors of powderiness and moisture,fragrance and sweetness were the largest.The nutritional quality indexes were simplified into 4independent principal components,and the feature vectors of the contents of dry matter,Fe,B,Ca,Zn,total flavonoid,chlorogenic acid,a*and b* value(representing the carotene content)were the largest.Further correlation analysis showed that the 11 key qualities factors of storage roots of nine edible sweetpotato varieties were the chroma a*and b* value,powderiness and fragrance of steamed storage roots,and contents of dry matter,total flavonoid,chlorogenic acid,Fe and B,Ca and Zn in fresh storage roots,respectively.The subordinate function mean(K)of 11 key factors of nine varieties were ranked as Qinshu No.5 > Zhongshu No.1 > Wanshu No.10 > Guangshu 87 > Yanshu 25 > Shangshu 19 >Wanshu No.7 > Jishu 26 >Longshu No.9.Conclusion: Edible-using sweetpotato variety could be divided into the very early type for eating and process(Longshu No.9 and Wanshu No.7),the earliness type for eating andprocess(Zhongshu No.1,Shangshu 19,Wanshu No.10 and Jishu 26)and conventional type for eating(Qinshu No.5,Guangshu 87 and Yanshu 25),and the first and second types would be the direction of edible sweetpotato breeding in the future.The chroma a*and b*,powderiness and fragrance of steamed storage roots,and contents of dry matter,total flavonoids,chlorogenic acid,Fe and B,Ca and Zn in fresh storage roots would be used as an important indexes of edible sweet potato breeding.The comprehensive edible-using type of nine varieties and the scores of key factors indicated that the breeding of high quality and precocious edible type still needs further efforts,Zhongshu No.1 and Wanshu No.10 would be recommended to be used in the fresh eating and food processing sweetpotato industries. |
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