| Sweetpotato(Ipomoea batatas Lam.) is one of the important upland crops in Guizhou, distributing mainly in Tongren, Zunyi, southeast of Guizhou, Sweetpotato germplasm resources are abundant with long-term cultivation. About 25 local and 20 introducing resources were determined on agronomic traits of shape and yield and ISSR analysis of genetic diversity, genetic relationship between domestic bred and Guizhou local varieties was obtained in the experiment. Certain theoretical basis on Sweetpotato cross breeding were hoped to provide in the paper. Main research results are as follows:1. Agronomic characteristics of 45 Guizhou sweetpotao germplasm resources diverse obviously. Sprout time is always between 30～40 days along seedling stage between 50～65 days; crawling, stand straight partly were the form of the plant; the harmonious type has the heart-shaped, heart-shaped, shallow single point incision shape and the incision shape with the tray; the harmonious color has green, strong green and green belt are purple; the color of the stem pole is green and green purple; the Stem thickness was between 0.44～0.75 cm, the maximum spread was between 35～142cm, the base branch was between 3～16 plant; Sweet potato flesh is white, yellow, light yellow or purple; the color of sweet potato peel is red, white, yellow or light red etc; there are potato-shaped spindle, spherical, long-spindle, the up spindle and lower spindle; the number of tubers in 2.2～4.6/plant, plant tubers 0.29～1.04 kg/line; the production of fresh potato during in 1151～4126kg/mu; drying rate of 13.5～31.4%, and the senior cadres of the rate of less resources.2. OD260/OD280 of Guizhou Sweetpotao germplasm genomic DNA is between 1.8～2.1. Agarose gel electrophoresis showed extracted DNA bands were single, neat and integral extracted DNA met the requirements of ISSR molecular markers.Althogonal experiment were done to optimize the 5 factors:templates, formamide, dNTP, primer, TaqDNA polymerase which affect ISSR-PCR reactions. The results showed treatment 10 were best,20μL reaction system contains 10 times diluted DNA template,0.30 mmol/L dNTP,1.00 fimol/L primer,1.00 U Taq enzyme,0.5% to ion formamide DNA.3. 52 bands were amplified using seven primers with 7.7 bands per primer on average. Among the 52 bands,49 of them were polymorphic, the percentage of polymorphic was 94.2%. 4. According to morphological clustering, average euclidian distance is 5.0, euclidian distance for Guizhou purple coat yellow heart and TongZi red coat and heart is 0.99, which is nearest; the farest euclidian distance is 8.5 for Tongren yellow coat orange heart and Tianzhu red coat. The 45 Guizhou sweet potato varieties can be classified to three groups, the first class includes 32 varieties, Guizhou purple coat yellow heart and TongZi red coat and heart, etc; The second class includes 12 varieties, Fushu 8, Tianzhu yellow heart and Shenglibai, etc. the third class includes only Tianzhu yellow coat. 5. According to ISSR molecular marker clustering.The variation coefficients of the 45 sweet potato varieties in Guizhou is 0.07～0.81, average coefficient is 0.4, which indicates that relationship of the 45 sweetpoato resources in Guizhou is closed, The highest variation coefficient is 0.81 for Sinan yellow coat orange heart and ShiQian purple coat yellow heart, the lowest variation coefficient is 0.07 for Weng'an white coat white heart and Tongren yellow coat orange heart. According to the clustering figure generated by ISSR marker, the 45 sweet potato varieties were divided into 5 kinds, the first kind includes 35 varieties, Pushu 53, Xushu 22, Xushu 25 etc. the second kind includes 6 varietes, Dushan purple heart sweet potato, Huangping purple coat yellow heart and Dushan red coat yellow heart, that are all the local varieties; the third kind includes Tianzhu yellow heart and Guizhou white coat sweet potato; Kaili purple coat red heart and Shiqian purple coat yellow heart belongs to the forth and the fifth kinds, both of them include only one variety.
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