Effects of Soil and Environment on Quality Traits of Purple-fleshed Sweetpotato

For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuzhou separately. The main quality traits were determined. The results showed the quality traits of purple-fleshed sweetpotato were significantly influenced by soil and ecological environments. Geno- type （G）, environment （E） and genotype x environment （GxE） interaction had signif- icantiy effects on the contents of anthocyanin, dry matter, starch, protein, reducing sugar and soluble sugar in storage roots. Anthocyanin content was most easily af- fected by the environment. The E effect on anthocyanin content was greater than G and GxE effects. However, the GxE interaction effects on other 5 quality traits were greater than G and E effects. The 6 quality traits were significantly different at 1% level under different environments respectively. The contents of dry matter, starch and anthocyenin were higher in Yancheng than in Xuzhou, while the contents of protein, reducing sugar and soluble sugar were higher in Xuzhou. The variation co- efficients of all quality traits at Yancheng and Xuzhou were in the same order： an- sugar〉protein〉starch, the variation coefficient of anthocyanin content was higher in Xuzhou, and the variation coefficients of other 5 traits were higher in Yancheng. Correlation analysis showed that the reducing sugar and solu- ble sugar contents were negatively correlated with starch content, and had no sig- nifiant correlation with anthocyanin and protein contents. Dry matter content and starch content were positively correlated, and anthocyanin content and other quality traits had no significant correlation.

Analysis on the Essential Characters and Biological Yield Change of Purple-fleshed Sweetpotato Xuzishu 3

Objective] This study was performed to investigate the trait changes and their correlations as wel as the dynamic changes of biological yield of Xuzishu 3, which wil help to enhance the yield and anthocyanin content of sweetpotato by cul-tivation. [Method] We systematical y measured the agronomic traits, qualitative char-acters and biological yield of Xuzishu 3 during six growing periods to investigate the dynamic changes of its essential characters and yield accumulation. [Result] The characters of Xuzishu 3 appeared most prosperous after the 90th d except for an-thocyanin content. Extremely significant positive correlations were found between ev-ery two of the dry matter rates of above-ground parts （including leaf petioles, leaves and stems）, reducing sugar content and potato weight per plant. Assimilated product distributed more in stems and leaves than in storage roots before the 90th d in growing period. Photosynthetic capacity and net assimilation rate gradual y de-creased after the 90th d, but the assimilated product distributing to storage roots in-creased quickly and maximized in the 135th d. [Conclusion] Xuzishu 3 is a late ma-turing variety requiring more fertilizer, and the accumulation of anthocyanin fluctuates during the growth period of Xuzishu 3. So yield of Xuzishu 3 can be increased by applying more fertilizer and extending the growth period reasonably, meanwhile the anthocyanin content can be increased by means of control ing temperature, light, water and phytohormone within 60 d after planting.

Variation Laws of Anthocyanin Content in Roots and Their Relationships with Major Economic Traits in Purple-Fleshed Sweetpotato Ipomoea batatas (L.) Lam

Variation laws of anthocyanin content in root during the development and among the varieties, and their relationships with major economic traits in purple-fleshed sweetpotato [Ipomoea batatas （L.） Lam] were studied in the present article. The dynamics of 20 economic traits in 13 purple-fleshed sweetpotato varieties at 20, 40, 60, 80, 100, 120, and 140 d after their transplanting were investigated, and these traits included anthocyanin content in root, length of the longest vine, number of base branches, root number, dry matter contents in stem, foliage and root, fresh/dry weight of root, fresh/dry weight of stem, flesh/dry weight of foliage, flesh/dry weight of stem and foliage, flesh/dry weight of whole plant, and rations of photosynthate to root, stem, and foliage. The correlations between the variations of anthocyanin content and the other 19 economic traits among varieties and during the whole developing stages, and the correlations of daily increase of anthocyanin content with other l0 kinds of yields were analyzed. The results showed that： （1） During the whole development, the anthocyanin content had three variation types, i.e. a slow-increase type, a fluctuating-change type, and a deviousrising type, and had different responses to the growth of length of the longest vine, number of base branches, flesh/dry yield of root, and photosynthate allotments. （2） The anthocyanin contents among 13 varieties began to have significant difference after 20 d, and showed completed differentiation during 40-100 d, which had significantly negative correlationships with the number of base branches, fresh/dry yield of root, photosynthate allotment ratio to root, and had significant positive correlationships with dry matter content of root, length of the longest vine, fresh/dry yield of stem, dry yield of whole plant and photosynthate allotment ratio to foliage. （3） Because of the significantly negative correlation between daily increase of anthocyanin content and dry matter weight of root, the anthocyanin accumulation competed with dry matter accumulation for photosynthate in root, and the competitive relation was resolved in different ways in different purple-fleshed sweetpotato （PFSP） varieties. So, there had three variation types of anthocyanin content among PFSP varieties during their development, and had different correlations between these variations of anthocyanin content and the major economic traits.

Coronatine Induces an Accumulation of Anthocyanin and Starch in Purple-fleshed Sweetpotato(Ipomoea batatas Lam.)

[Objective] The objective of this research was to examine the effects of COR on anthocyanin and starch content in storage roots of two PFS genotypes, and to explore the relationships between anthocyanin synthesis and starch accumula- tion. [Method] A field experiment was carried out to determine the changes in yielc components, yield, contents of anthocyanin and starch, activities of phenylalanine ammonia-lyase （PAL） and adenosine 5-diphosphate glucose pyrophosphorylase （AG- Pase） in two genotypes of PFS （Ipomoea batatas L., var. ＇Ayamurasaki＇ and ＇Jishu18＇）. [Result] The application of COR significantly increased starch and antho- cyanin content in storage roots of Jishu18 across developmental stages by inducing the activities of PAL and AGPase, and finally enhanced yield by promoting fresh weight of storage roots. Ayamurasaki was insensitive to treatment with COR al- though its PAL activity temporally increased. The starch and anthocyanin content of Aya, and the anthocyanin content of Jishu18 increased progressively across devel- opmental stages with or without COR application, but the starch content of Jishu18 increased initially, then decreased before increasing again without application of COR. Treatment with COR reduced downward trend of starch accumulation in Jishu18. Thus, the effect of COR on accumulation of anthocyanin and starch in storage roots of PFS differs according to genotypes. [Conclusion] The application of 0.05 μmol/L COR may increase starch and anthocyanin content in PFS genotypes with lower starch and anthocyanin content in storage roots.

Optimal Technique for High Yield of Purple Flesh Sweetpotato in Chongqing

[Objective] The aim was to obtain the best planting density and the best fertilizer of purple flesh sweetpotato so as to provide theoretical basis for breeding of high yield and quality of purple flesh sweetpotato in Chongqing.[Method] The effects of fertilization,planting density and variety on yield of purple flesh sweetpotato were studied by orthogonal test of L9（34）.Residential treatment was：fertilization（A）,300 kg/hm2（A1）,600 kg/hm2（A2）,900 kg/hm2（A2）;density（B）,45 000 Plants/hm2（B1）,60 000 Plants/hm2（B2）,75 000 Plants/hm2（B3）;species（C）,Wanzi 56（C1）,Yuzi 43（C2）,Yuzi 263（C3）.[Result] The yield of Wanzi 56 was the highest among three purple flesh cultivars on conditions that planting density was 75 000 plants/hm2,and fertilization was 300 kg/hm2.The influence of planting density for yield of purple flesh sweetpotato was higher than that of fertilization.The orders of different levels of various factors on the test results was A factor column,K1〉K2〉K3;B factor column,K3〉K1〉K2;C factors column,K1〉K3〉K2.[Conclusion] The yield of Wanzi 56 was highest,follow by the yizi263 and yuzi43.The optimum planting density was 75 000 plants/hm2,and the most reasonable amount of fertilizer was 300 kg/hm2.