Genome-wide recombination variation in biparental segregating and reciprocal backcross populations provides information for introgression breeding in Brassica napus  

作　　者：Meng Wang Graham J.King Lei Shi Ruiyuan Li Yi Zhang Xiaohua Wang Jinling Meng Jinxing Tu Jun Zou 

机构地区：[1]National Key Laboratory of Crop Genetic Improvement,Huazhong Agricultural University,Wuhan 430070,Hubei,China [2]Southern Cross Plant Science,Southern Cross University,PO Box 157,Lismore,New South Wales 2480,Australia [3]Key Laboratory of Information and Computing Science of Guizhou Province,Guizhou Normal University,Guiyang 550001,Guizhou,China [4]College of Agriculture and Forestry Science,Linyi University,Linyi 276000,Shandong,China

出　　处：《The Crop Journal》2023年第1期208-219,共12页作物学报（英文版）

基　　金：supported by the National Key Research and Development Program of China (2021YFF1000100);the National Natural Science Foundation of China (31970564 and 32171982);the National Key Research and Development Program of China (2016YFD0100305)。

摘　　要：Variation in patterns of recombination in plant genomes provides information about species evolution,genetic diversity and crop improvement. We investigated meiotic crossovers generated in biparental segregating and reciprocal backcross populations of the allopolyploid genome of rapeseed(Brassica napus)(AACC, 2n = 38). A structured set of 1445 intercrossed lines was derived from two homozygous de novo genome-assembled parents that represented the major genetic clusters of semi-winter Chinese and winter European rapeseeds, and was used to increase QTL resolution and achieve genomic reciprocal introgression. A high-density genetic map constructed with 6161 genetic bins and anchored centromere regions was used to establish the pattern of recombination variation in each chromosome. Around 93%of the genome contained crossovers at a mean rate of 3.8 c M Mb^(-1), with the remaining 7% attributed to centromeres or low marker density. Recombination hotspots predominated in the A genome, including two-thirds of those associated with breeding introgression from B. rapa. Genetic background might affect recombination variation. Introgression of genetic diversity from European winter to Chinese semi-winter rapeseed showed an increase in crossover rate under the semi-winter environment. Evidence for an elevated recombination rate having historically contributed to selective trait improvement includes accumulation of favorable alleles for seed oil content on hotspots of chromosome A10. Conversely, strong artificial selection may affect recombination rate variation, as appears to be the case with a coldspot resulting from strong selection for glucosinolate alleles on A09. But the cold region would be promptly reactivated by crossing design indicated by the pedigree analysis. Knowledge of recombination hotspots and coldspots associated with QTL for 22 traits can guide selection strategies for introgression breeding between the two gene pools. These results and rich genomic resources broaden our understanding of recombination behav

关 键 词：ALLOPOLYPLOID Meiotic crossovers Brassica napus Historical introgression Reciprocal backcross population 

分 类 号：S565.4[农业科学—作物学]