Study On Establishment And Application Of RAPD Technique In Pyrus L.

Pyrus plants belonged to Rosaceae, Pomaceae, Pyrus L. There were more than 60 species in the world, which were distributed over Europe, Asia, North America and the Temperate Zone area of the Southern Hemisphere. One of the origin centers of Pyrus was China, which was abundant in Pyrus germplasm resources deposits. Yali pear and it's mutation types and other 44 Pyrus plants were studied using RAPD (Random Amplified Polymorphic DNA) technique. This study aimed at discussing the feasibility of RAPD applying on Pyrus germplasm resource, delving the function of RAPD in bud mutation identification of fruits. This study also aimed at delving and clearing the genetic relationships of partly Pyrus germplasm, which could find out the ownership of some cultivars, such as Pingguoli and so on. The main results were as follows:1. The optimized RAPD reaction system was established: in a total volume of 25 L, containing 100mM KC1, 8mM (NH4)2SO4, 10mM Tris-HCl(pH9.0), 2.0mM MgCl2, 200 M dNTP, 0.4 M primer, 40 ng template DNA, 1.5U Tag DNA polymerase. This condition was similar to those obtained in other labs, with little different in the concentrations of primer, Taq DNA polymerase and Mg2+.2. 18 primers selected from 50 ones were identified to be high polymorphic and were applied on RAPD amplification of 44 Pyrus plants. The amounts of bands were 4-11 and the molecular weight mainly was 450bp-2000bp. A total of 118 DNA bands were amplified, including 11 same bands and 107 polymorphic bands.3. Yali pear and it's mutations were studied using RAPD technique at the first time. Four primers were selected from 50 ones. They were S28, S32, S176, and S1450. Theresults amplified based on the four primers as follows:(1) Compared to other mutations, the RAPD amplification of ChuizhiYali pear existed one specific band: S32-600.(2) Compared to other mutations, all of the RAPD amplifications of WeixianjuYali pear, TianYali pear and ChuizhiYali pear were short of two specific bands: S28-400 and S28-650.(3) Compared to other mutations, both of the RAPD amplifications of WeixianjuYali pear and Yanzhuangzihua Yali pear were short of two specific bands: SI76-900 and S176-1150.(4) There was no polymorphism among the mutation types, which were polymorphic by primer S1450, but the abundance of S1450-750 of JinxiandaYali pear was changed. The band S1450-750 of JinxiandaYali pear was one strong band, but that of others was one weak band.4. Basing on the RAPD data obtained, clustering analyses on the 44 materials of Pyrus were carried out, and the tree diagrams were established by Ward method. The relationships within different systems of Pyrus were discussed.5. Aiming at the existent demurral on systematic status of Pingguoli pear, we considered that Pingguoli should belong to White-pear system.6. Aiming at the existent demurral on systematic status of Ku'erlexiangli pear, we considered that Kuerlexiangli pear should belong to White-pear system.