介绍qtl及标记辅助选择等基本的概念Euphytica (2005)

Euphytica(2005)142:169–196

DOI:10.1007/s10681-005-1681-5C Springer2005 An introduction to markers,quantitative trait loci(QTL)mapping and marker-assisted selection for crop improvement:The basic concepts

B.C.Y.Collard1,4,∗,M.Z.Z.Jahufer2,J.B.Brouwer3&E.C.K.Pang1

1Department of Biotechnology and Environmental Biology,RMIT University,P.O.Box71,Bundoora,Victoria3083, Australia;2AgResearch Ltd.,Grasslands Research Centre,Tennent Drive,Private Bag11008,Palmerston North, New Zealand;3P.O.Box910,Horsham,Victoria,Australia3402;4Present address:Plant Breeding,Genetics and Biotechnology Division,International Rice Research Institute(IRRI),DAPO Box7777,Metro Manila,Philippines; (∗author for correspondence:e-mail:bcycollard@)

Received11July2004;accepted2February2005

Key words:bulked-segregant analysis,DNA markers,linkage map,marker-assisted selection,quantitative trait loci (QTLs),QTL analysis,QTL mapping

Summary

Recognizing the enormous potential of DNA markers in plant breeding,many agricultural research centers and plant breeding institutes have adopted the capacity for marker development and marker-assisted selection(MAS). However,due to rapid developments in marker technology,statistical methodology for identifying quantitative trait loci(QTLs)and the jargon used by molecular biologists,the utility of DNA markers in plant breeding may not be clearly understood by non-molecular biologists.This review provides an introduction to DNA markers and the concept of polymorphism,linkage analysis and map construction,the principles of QTL analysis and how markers may be applied in breeding programs using MAS.This review has been specifically written for readers who have only a basic knowledge of molecular biology and/or plant genetics.Its format is therefore ideal for conventional plant breeders,physiologists,pathologists,other plant scientists and students.

Abbreviations:AFLP:amplified fragment length polymorphism;BC:backcross;BSA:bulked-segregant analysis; CIM:composite interval mapping;cM:centiMorgan;DH:doubled haploid;EST:expressed sequence tag;SIM:sim-ple interval mapping;LOD:logarithm of odds;LRS:likelihood ratio statistic;MAS:marker-assisted selection;NIL: near isogenic lines;PCR:polymerase chain reaction;QTL:quantitative trait loci;RAPD:random amplified poly-morphic DNA;RI:recombinant inbred;RFLP:restriction fragment length polymorphism;SSR:simple sequence repeats(microsatellites);SCAR:sequence characterized amplified region;SNP:single nucleotide polymorphism; STS:sequence tagged site

Introduction

Many agriculturally important traits such as yield,qual-ity and some forms of disease resistance are controlled by many genes and are known as quantitative traits(also ‘polygenic,’‘multifactorial’or‘complex’traits).The regions within genomes that contain genes associated with a particular quantitative trait are known as quan-titative trait loci(QTLs).The identification of QTLs based only on conventional phenotypic evaluation is not possible.A major breakthrough in the characteri-zation of quantitative traits that created opportunities to select for QTLs was initiated by the development of DNA(or molecular)markers in the1980s.

One of the main uses of DNA markers in agricul-tural research has been in the construction of linkage maps for diverse crop species.Linkage maps have been utilised for identifying chromosomal regions that contain genes controlling simple traits(controlled by a single gene)and quantitative traits using QTL