Genetic Diversity Analysis And Establishment Of Molecular IDs Of Cultivars (Lines) In Loquat (Eriobotrya Japonica Lindl.)

52 loquat cultivars or lines were collected from Ya'an, Longquan and Fujian in this study.74 EST-SSR primers developed from peach were screened by testing polymorphism loci. Genetic diversity analysis was carried out on the 52 loquat materials and every loquat cultivar or line was issued a unique molecular ID. The main results were as follows:(1) 74 EST-SSR primers developed from peach were examined by agarose gel electrophoresis and polyacrylamidedel gel electrophoresis.43 primers amplified bands and out of them 36 were polymorphic.(2) 15 primers with high polymorphism, clear bands and high repetition rate were chosen for genetic diversity analysis. The analysis of polymorphism showed that 15 primers amplified a total of 74 bands and each pair of primers amplified 2 to 9 bands, with average of 4.93 bands. P06 and P59 showed high polymorphic (PIC>0.5). In general, most of the selected EST-SSR primers showed medium and high polymorphism.(3) According to the results of cluster analysis of 52 loquat cultivars or lines, SM coefficients of the 52 accessions in this study were between 0.80 and 0.96, indicating that the selected cultivars or lines had a close genetic relationship. All materials can be divided into four major categories at a 0.832 threshold of SM coefficient.'Ruantiaobaisha' from Zhejiang and 'Baiyu' from Jiangsu were included in group ?. Group ? consisted of 'Wugongbai' from Fujian province and No.24 from SAU biotechnology center. Group ? included three loquat materials collected from Longquan (LQ42, LQ45 and 'Longquan No.1') and No.40 from SAU biotechnology center. The last group mainly included most of the materials from SAU biotechnology center (LQ1-LQ23, LQ25-LQ39 and 'Baili').(4) The unique molecular identity cards of 52 loquat cultivars or lines were constructed with 15 EST-SSR primers. By fixing the primer sequence and chosing the smallest alleles for coding and assignment, the molecular identity cards would be convenient and easy in use.(5) 9 primers were selected for core primer screening and the best core primer combination was selected in each type of primer combinations. The most effective core primer combinations, composed of P06 and P59, could distinguish 26 loquat cultivars or lines, each pair of primers could distinguish 13 loquat cultivars or lines on average. According to the total and average number of loquat accessions that could be distinguished by primers,6 primers from the type of C69 combination were ultimately chosen for core primers in this study and they could distinguish 46 loquat cultivars or lines, with an average of 7.7 loquat cultivars or lines, ensuring the total and average number of loquat cultivars or lines distinguished by the primers.(6) Characteristic primers were identified for 30 loquat cultivars or lines.9 core primers could distinguish 49 loquat cultivars or lines,12 core primers could distinguish all the loquat cultivars or lines used in this study.