Studies On The Effects Of The Agronomic Measures In Sweet Potato With Different Dry Matter

As a raw material of bioenergy and starch prcessing, the starch content of sweet potato determines the fuel alcohol transform rate and the benefit of prcessing. There is an important route for enhancing the transform rate and the benefit of prcessing of sweet potato by advancing the starch content and breeding high starch high yield varieties. The experiment with different varieties of sweet potato, plus control of fertilizer (N: K₂O=1: 2) and take off branches, using L₉ (3⁴) orthogonal experimental design (a totally random field with group ), through the synthesis of starch-related activity of enzymes and agronomic traits to judge achieving the effect of impact for sweet potato starch content, and find appropriate control combination. In addition, the changes of the different periods and some certain target to found a certain rule, and predict the future content of the sweet potato starch. The main results are as follows:1. Various factors on the impact of the yield and the number of storage rootsIn this experiment the economic yield is higher which dry matter rate is lower. So it is two different processes for roots expansion and the dry matter accumulation. The genotype difference is the main factors for the economic yield. For this experiment the genotype difference is the main factors for the yield of starch and the number of storage roots.The nitrogenous and potassium fertilizer were not significant to the economic yield and the starch yield. The fertilizer did not impact the fall sweet potato abundant because of the harvest early.2. Various factors on the impact of dry matter rateThe genotype difference is the main factors for the dry matter rate. The dry matter rate is lower when the potassium is higher. In the growth, the time is longer for Yushu2 accumulation the dry matter rapidly than Nanshu88 and Shangqiu52-7. Except the difference of time, the dry matter rate is high because of the fresh weight upside are high. For sweet potato of high dry matter rate in order to advance the dry matter rate the best combination are 10 kg/667m² of nitrogen, 10kg/667m² of potassium and do not take off branches.3. Various factors on the impact of fresh weight upside and R/T. The genotype difference is the main factors for the fresh weight upside,R/T and chlorophyll content. The sweet potato of high dry matter rate has high fresh weight upside in the period of growth. 10 kg/667m² of nitrogen is good for advancing the fresh weight upside. For sweet potato of high dry matter rate in order to advance the chlorophyll content, the best combination are 10 kg/667m² of nitrogen, 5kg/667m² of potassium and do not take off branches.The sweet potato of high dry matter rate has high R/T. The nitrogen is likely to advance the dry matter in storage roots.4. Various factors on the impact of activity of enzymesThe genotype difference is the main factors for the activity of enzymes. The activity of ADPG pyrophosphate enzyme (AGPase) is higher which the dry matter rate are higher, and it is the time to accumulate the dry matter rapidly when the activity of AGPase is lower. The activity of sucrose synthase (SS) and sucrose phosphate synthase (SPS)are higher which the dry matter rate are higher.For sweet potato of high dry matter rate in order to advance the syntheses of starch-related activity of enzymes, the best combination are 5 kg/667m² of nitrogen, 20kg/667m² of potassium and do not take off branches.5. Various factors on the impact of sugar metabolize.In this experiment, the high dry matter rate species have low Deoxidize sugar,Soluble sugar content.Take off branches did not achieve significant or very significant to sugar content.In this experiment, the lower of sugar content is good for the starch accumulation, so the best combination are 5 kg/667m² of nitrogen, 20kg/667m² of potassium and do not take off branches.6. The relativity of the syntheses of starch-related activity of enzymes and sugar content.There achieve significant or very significant minus relativity between storage roots of dry matter rate,yield of starch and AGPase and SS.The exhibition is consistent between AGPase and SS in storage roots. They achieve very significant positive relativity. There do not achieve significant or very significant between SPS and AGPase.There achieve significant or very significant minus relativity between AGPase,SS and Deoxidize sugar,Soluble sugar content. There is more sugar in storage roots when the syntheses of starch-related activity of enzymes were lower.