The Effect Of Vine Characteristies And Fertilization On Formation Of Storage-roots Of Sweet Potato

Sweet potato (Ipomoea batatas (L.) Lam.), the important food, energy and industrial raw materials, and the improvement of yield was the breeding objectives of sweet potato. Intensive studies have established to improve the weight, enlargement of tuberous root and formation of output. In this study, change regularities of three utilized sweet potato varieties with different levels of starch contents were investigated using orthogonal test of L9(34) with fertilization levels,100-seedling weights and seeding segments. two parallel experiments were designed. In the one experiment, the varieties,100-seedling weights and fertilizer levels were used as the three factors; In the other experiment, the three factors were varieties, seeding segments and fertilizer levels. Through the analysis on physiological indexes, growth vigor and root characteristics, the effect of fertilization,100-seedling weights and seeding segments treats were studied. The regular factors of the formation and development of tuberous roots, and the measures that promote the amounts of tuber per plant were discussed. The results are as following:1.The influence of each factor on above ground part of sweet potato.For the variety "Nanshu88", the maximum vine thickness and leaf area index (LAI) were obtained, and the length of longest vine was comparatively high. stem-leaf natural weight of "Nanshu88" were significantly higher than another two varieties in the second expriment, and were comparatively high in the first experiment.Stem-leaf natural weight, LAI and the length of longest vine were significantly higher at high fertilizar level when compared with low level, and were increased with the increase of fertilization, while vine thickness have not obvious difference.The maximum vine thickness of seeding with maximum 100-seeding weight were higher than seeding with low 100-seeding weight, while LAI of which were lower than another two treats at 39 days after planting. The length of longest vine and stem-leaf natural weight of middle 100-seeding weight were highest at 39d after transplanting.2. The influence of each factor on sweetpotato physiological indexes.Total sugar contents and C/N ratio in leaves of "nanshu88" higher than the other two varieties, and nitrogen content minimum. N/K ratio in two experiment significantly lower than the other two varieties, and root vigor of "nanshu88" drop early, which is minimum in three varieties 39d after transplanting.The difference fertilization makes N, P, K Contents in leaves of sweet potato increased significantly with the increase of fertilizer, but N/K ratio of Low-fertilizer levels is significantly less than High-fertilization level, Total Sugar Content is significantly higher than High-fertilizer levels, and its C/N ratio significantly higher than High-fertilization level, non-fertilizer levels's root vigor drop early, but three levels is no significant difference 39d after transplanting.sweet potato of strong-seedling N contents in leaves is significantly lower than the weak-seedling, P content is higher than weak-seedling,K contents is middle levels,and N/K ratio significantly less than weak-seedling, Total sugar contents are no significant difference between every seedling weight treatment,but N/K ratio of strong-seedling is significantly higher than weak-seedling, the root vigor is no significant difference between three treatments.N, P, K contents of vine-segment treatment is no significant difference,but N/K ratio of top-segment vine lower than the other vine-segment treatment,and its root vigor drop early, but three treatments is no significant difference 39d after transplanting,mid-segment vine have the highest total sugar contents,C/N ratio is no significant difference between three treatments. 3. The influence of each factor on sweetpotato root formation and developmentIt is higher than the other two varieties to root weight, root volume, roots number and storage-roots number of "nanshu88".Root development, storage-roots formation and swollen ability of no-fertilizer levels are all best.and the root weight, root volume, and storage-roots are significantly higher than other fertilizer levels.Strong-seedling cultivation, the root weight, root volume, and storage-roots number significantly higher than the weak seedling.Root development, storage-roots formation and swollen ability of top-segment vine are better than other vine segment treatment,it performance the root weight, root volume, and storage-roots are biggest.