The Study On The Characteristic And Expansion Of A Superior Quality Sweet Potato Species-LU SHU 8

LU SHU 8 is a multi-used variety with the characteristic of high yield, superior quality and anti-disease, which is bred by Taian gricultural Science Institute. In order to develop fully the function of LU SHU 8 in the agricultural producing, the characteristic, growing regulation, anti-disease, and special cultivation technique are studied in this paper. The results are as follows: (1)LU SHU 8 grew rapidly in the earlier stage, the LAI (Leaf Area Index) increased quickly. The ridges of the field started to be sealed in July, 70 days later after being planted, and the LAI became to 3. During 70 to 110 days after being planted, the LAI increased smoothly. On the 80^th day after being planted, the LAI became to 4.4. A bigger photosynthesis area had been formed in the former time and the photosynthesis areas could maintain smoothly for a long time. On the 110^th day after being planted, the LAI became to 5.1, which is biggest in the growing period, the photosynthesis areas had been increased and the light utilization had been improved. On the 140^th day after being planted, the LAI became to3.64, which was very fast to reduce the LAI. At the same time, the carbohydrates accumulated by the plants above the ground were transported to the root tuber under the ground. On the 170^th day after being planted the LAI became to 2.67 and LU SHU 8 had no senilism phenomenon. In a word, LU SHU 8 grew rapidly in the earlier stage and smoothly in the mid term. There was not senillism phenomenon in the later stage. (2)The root tubers of LU SHU 8 expanded obviously in two periods. The first period is about during 50^th to 80^th day and the second period is about during 110^th to 140^th day after being planted. The root tubers of LU SHU 8 formed earlier and expanded more quickly than other species.(3)The T/R of LU SHU 8 was 6.18 and 3.44 on the 50^th and 80^th day after being planted. On the 135^th day after being planted the ratio became to 1, so itwas suitable for the balance point to appear in the growing period. The plants above the ground grew quickly in the earlier stage, but did not grow in vain. When the nutrition growth reached to some degree, the root tubers expanded more quickly and the stems and leaves grew more slowly, so the two parts got a balance each other. In the later stage, the transportation of nutrition from above the ground to the under ground part in the plants was more quick. At harvest time, the 170th day after being planted, the T/R was 0.66. The photosynthesis production was distributed properly, hi a word, the plant growing of LU SHU 8 and its root tuber expansion could coordinate with each other. The balance point of growth appeared a little earlier but not too earlier. The nutrition distribution between the above ground plant and the root tuber was reasonable.(4)The dry materials of LU SHU 8 accumulated rapidly and the economic coefficient was high. On the 80th day after being planted, the dry weight of biology yield of LU SHU 8 was 112.25 gram per plant, the dry weight of economic yield was 36.6 gram per plant and the economic coefficient was 0.326. On the 170th day after being planted, the dry weight of biology yield of LU SHU 8 was 344.16 gram per plant, the dry weight of economic yield was 316.26 gram per plant and the economic coefficient was 0.919. During the whole growing period, the dry weight of biology yield and economic yield and the economic coefficient of LU SHU 8 were higher than XU SHU 18 and BEI JING 553. In the earlier stage, 80 days after being planted, the increasing extent of biology yield of LU SHU 8 was bigger, the plants grew earlier, the photosynthesis yield was more than other two varieties, hi the later stage, the increasing extent of economic yield of LU SHU 8 was bigger, the nutrition distributed to the above ground plant was more than that distributed to the root tubers, so the most of dry materials were transported to the root tubers, the capability of the root tubers were enlarged and the yield was improved.(5)LU SHU 8 was a superior species of high amylum and high sugar, which had the advantages of XU SHU 18 and BEI JING 553 and which was a multi-used species. The roasting ratio was 33.37 percent, the wet amylum content was 23.05 percent, the soluble sugar content in the fresh sweet potato was 5.27 percent, the carotene content in the fresh sweet potato was 3.42milligram per 100 gram and the protein content was 7.8 milligram per 100 gram.(6)LU SHU 8 had a high capability of anti-stress, and resisted the root rot disease and caulis nematode disease.(7)The summaries of getting a high yield are as follows:1. Cultivate the strong seedlings without germ and illness.2. Plant the seedlings at a proper time and on a proper density. The spring sweet potato should be planted when the ground temperature during 5 centimeter to 15 centimeter steady at 15 degrees of Celsius and the temperature steady at more than 18 degrees of Celsius, which means during April 29 to May 4. The density of planting the seedlings is between 3344 plants and 3607 plants per 666.7 square meters.3. Optimize fertilizers. The main fertilizers are organic manure cooperating with some nitrogen, phosphate and potassium fertilizers. Pre 666.7 square meters, we should use Urea between 1.38 kilograms and 3.01 kilograms, lead the calcium phosphate between 64.84 kilograms and 71.30 kilograms, Sulfuric acid potassium between 32.31 kilograms and 37.68 kilograms. We should use enough basic fertilizers, but when the basic fertilizers are not enough or the growth condition is not well, we should supple the fertilizers in time in order to accelerate the growth. We should fertilize little or no in the later stage.4. Reinforce the field management and prevent the illness and insect, hi addition to inspect the seedling, cultivate to weed, add fertilizer and earth up, we should prevent from water and against drought and cure the plant disease and insect pests. If the spring drought is very serious, we should water in time, but the first time should not too early, it can be done in the middle or later of Mary. To prevent ground temperature drop and effect the growth of seedling, little water is adapt. Because LU SHU 8 is easy to be infected the black spot disease, we should carry out crop rotation.