Study On Origin Of Natural Hybrids In Elymus L.based On Acc1,Pgk1 And TrnL-F Genes(Poaceae,Triticeae)

Natural hybridization between different genera and different species in Triticeae was often reported in the past.Liu(2007)reported eight pentaploid hybrid plants(SH01-SH08,2n=35,StStHHY)and two tetraploid hybrid plants(SH09 & SH10,2n=28,StStHH).In order to explore the putative parents and origin of these 10 natural hybrids,two nuclear genes(Acc1 and Pgk1)and one chloroplast gene(trn L-F)were used in this study to analyze the possible parental and mechanism of these natural hybrids.The main results were showed as follows:1.45 Acc1 sequences,42 Pgk1 sequences and 10 trnL-F sequences were cloned and sequenced from ten natural hybrids(SH01-SH10)2.Pentaploid natural hybrids(SH01-SH08)had two different types of the St genome and H genome and one type of Y genome.The genomic composition of pentaploid natural hybrids is St1St2H1H2 Y.Tetraploid natural hybrid(SH09& SH10)had two different types of the St genome and one type of H genome.The genomic composition of tetraploid natural hybrids is St1St2 HH.3.The results of phylogenetic analysis based on two nuclear genes(Acc1 and Pgk1)and one chloroplast gene(trn L-F)showed that(1)C.breviaristata and E.sibiricus are the parents of natural hybrids of SH01,SH02,SH03,SH05,SH06 and C.breviaristata is the maternal donor;(2)C.nutans and E.sibiricus are the parents of natural hybrids of SH04 and SH07 and C.nutans is the maternal donor;(3)C.dahurica var.tangutorum and E.sibiricus are the parent of the natural hybrids of SH08 and C.dahurica var.tangutorum is the maternal donor.(4)E.sibiricus and an unclear species of Elymus are the parent of the natural hybrids of SH09 and SH10 and E.sibiricus is the maternal donor.