Evidence of widespread hybridization among couch grasses(Elymus,Poaceae)  

作　　者：Romana Urfusova Vaclav Mahelka Frantisek Krahulec Tomas Urfus 

机构地区：[1]Department of Botany,Faculty of Science,Charles University,Benatska 2,Prague CZ-12801,Czech Republic [2]Institute of Botany,Czech Academy of Sciences,Zamek 1,Prague CZ-25243,Czech Republic

出　　处：《Journal of Systematics and Evolution》2021年第1期113-124,共12页植物分类学报（英文版）

基　　金：Frederick Rooks kindly improved the English of our submission.This study was supported by the Grant Agency of Charles University(Project No.1358218);the Czech Science Foundation(Grant No.17-06548S);the Czech Academy of Sciences(long-term research development project RVO 67985939);the Charles University Research Centre(Programme No.204069).

摘　　要：Hybridization,polyploidization,and crop-to-wild gene transfer within the agriculturally important tribe Triticeae are well explored experimentally,but the true consequences of both phenomena under natural conditions remain understudied.The present paper reports on an investigation of three species of couch grasses(Elymus hispidus,E.repens,and E.caninus)examining the ploidy levels and absolute genome sizes(1081 plants from 302 natural populations in Central Europe,verified by chromosome counts)and their morphological delimitation.In the present study,the hexapioid level prevailed in E.hispidus and E.repens whereas E.caninus was exclusively tetraploid.Introgressive hybridization between hexapioid species,unidirectionally shifted towards E.hispidus,was indicated by a continual pattern of genome size values.We did not find any evidence for heteroploid hybridization involving tetraploid E.caninus;however,we detected minority cytotypes among both E.caninus plants(hexapioid)and E.repens-E.hispidus hybrids(heptapioid and nonaploid)suggesting the formation of unreduced gametes.Morphometric results(367 plants,redundancy analysis,principal component analysis,and correlation analysis)mirrored the continual homoploid pattern of absolute genome size(including the unidirectional shift),and a significant correlation between absolute genome size and morphology was confirmed.Moreover,morphometric analyses detected additional characteristics for the delimitation of the Elymus taxa under study.Considering the crossability of E.hispidus with Triticum aestivum(bread wheat),the revealed extent of introgressive hybridization has implications for assessing the potential risk of gene flow between crops and troublesome weeds.

关 键 词：absolute genome size couch grass ELYMUS HYBRIDIZATION INTROGRESSION ploidy level Thinopyrum 

分 类 号：Q94[生物学—植物学]