英语文档的作业.doc

Construction DNA fingerprinting of Ixeris polycephala varieties (lines) baesd on EST-SSR and SRAP markers BAN Qian1, HUANG Lin-kai1, ZHANG Xin-quan1*, （Department of Grassland Science, Sichuan Agricultural University, Chengdu 611130, China） AbstractIxeris polycephala is excellent grass-fodder annual Asteraceae forage With the intention of construction DNA fingerprinting among 14 Ixeris polycephala varieties (lines), twenty four of 152 EST-SSR primers and 32 of 209 SRAP primers were screened according to clear bands and high polymorphic imformation. Total of 270 bands including 223 polymorphic bands had been amplified from 24 EST-SSR primers, the polymorphism information content values reached 0.834. The Nei’s gene diversity (H) values ranged from 0.2464 to 0.4288, and the Shannon’s information index (I) values ranged from 0.3597 to 0.6148, the distinguished varieties (lines) number ranged from 3 to 14. Thirty two SRAP primers detected 367 polymorphic bands and the average value of polymorphism information content was 0.826. The Nei’s gene diversity (H) values ranged from 0.2006 to 0.3898, and the Shannon’s information index (I) values ranged from 0.3167 to 0.5716, the distinguished varieties (lines) number ranged from 2 to 12. Nine varieties (lines) emerged special bands on 7 primers, and took comprehensively consideration of each genetic diversity index, obtained a total of 40 polymorphic bands from 5 core primers (IpSSR102、IpSSR80、IpSSR91、Me10+Em5、Me9+Em17)for DNA fingerprinting construction of 14 Ixeris polycephala varieties (lines), and each varieties (lines) had a molecular standard DNA fingerprinting code. Key Words: Ixreis polycephala variety (line); EST-SSR marker;SRAP marker; Core primer; DNA fingerprinting INTRODUCTION MATERIALS and METHODS Plant materials A total of 30 samples were used in this study(Table 1). Most of new lines were from Forage Research Center in Sichuan Agricultural University and were originally collected in 2000-2010 by former breeder