讲 座 提 纲讲 座 提 纲 1 什么是分子育种 2 历史回顾 3 全基因组策略 4 基因型鉴定 5 表现型鉴定 6 环境型鉴定 (etyping) 7 标记 - 性状关联分析 8 标记辅助选择 9 决策支撑系统 10 展望

Marker-Assisted Selection Models I. Major gene introgression (target genes only) markers for each trait Single trait introgression Multiple trait introgression A few markers for hundreds of plants II. Marker-assisted backcrossing (target genes plus background) markers for each trait markers for background selection A few hundreds of markers for hundreds of plants III. Whole genome selection 500 to several thousands or millions of markers for hundreds or thousands of plants/lines

Xu et al 2012 Mol Breed 29:833–854 Marker- Assisted Selection Methods

Genomic Selection Phenotypic selection for complex traits is difficult and slow; traditional MAS is ineffective. Genomic selection, as an example for genomewide selection, is poised to revolutionize plant breeding, because it  uses marker data to predict breeding line performance in one analysis  analyzes the breeding populations directly  includes all markers in the model so that effect estimates are unbiased and small effect QTL can be accounted for

Genomic Selection in a Plant Breeding Program Heffner et al 2010 Crop Science 49:1-12 Genomic selection reduces cycle time & cost by reducing frequency of phenotypingTraining

Number of markers and genome coverage Markers types: single, haplotypes Population structure Population size Relationship between training and breeding populations Involvement of known genes and their markers Precision of phenotyping for training model development Heritability of target traits Key factors Affecting Genomic Selection

Genetic Gain under Whole Genome Strategies Genetic gain: concept development from quantitative genetics to molecular breeding Genetic gain per unit time can be defined as R = V g 1/2 h 2 i t V g : genetic variance h 2 : heritability i: selection intensity t: cycle time

Unlocking genetic variation from original ecotypes of cultivated species and their wild relatives Single markers Structure variation Haplotypes Across elite lines Across ecotypes Across wild relatives Within-gene haplotypes Within-chromosome haplotypes Within-genome haplotypes VgVg

h2h2 Precision phenotyping: more replications, MET Etyping and environmental error control i Increasing population size and thus the selection intensity Selection with seed DNA Selection in tissue culture Selection in gametophytic stage Selection in greenhouse phytotron, growth chamber Using of model plants Improvement of heritability estimation

t Shorten cycle time through MAS Increasing selection efficiency and accuracy using MAS Speeding up pure-breeding process (DH etc) Speeding up growth and development Using greenhouse etc Moving to the breeding objective quickly See examples for marker development and application from B.M. Prasanna (2014)