Molecular Cytogenetic Identification Of Wheat-elymus Repens Translocation Lines

Wheat(Triticum aestivum L.)is the earliest domestication and most widely planted crop.It feeds 35%of the world's population due to its high yield,nutrition value,wide distribution,and the role in food trade across the world.However,due to its limited genetic diversity,bread wheat is constantly threatened by various abiotic and biotic factors,which has limited its improvements in yield and quality.Thus the crop genetic improvement and new varieties breeding are the effective ways to solve these problems.Triticeae(Poaceae)includes many wild species,which can provide potential genetic resources with the enhanced resistance to stress environment such as diseases,insect pests,drought,and salinity.An efficient strategy to broaden the genetic base of wheat is to introgress some useful genes of its wild relatives into wheat through distant crosses.Elymus repens(L.)(2n = 6x = 42,StStStStHH)is a hexaploid perennial wheatgrass species from the tribe Triticeae,distantly related to bread wheat Triticum aestivum L.(2n = 6x = 42,AABBDD)and plays a vital role in the tertiary gene pools of common wheat.It not only has the characteristics of cold tolerance,dought tolerance,salt tolerance,but also is an important gene resource for improving the yield,quality and resistance of common wheat.In this study,wheat-E.repens hybrid derived progenies were crossed with the good wheat varieties or lines of Sichuan.4 wheat-E.repens translocation lines K15-1194-2,K15-1192-2,K15-1155-6 and K15-1211-1 were successful acquired.And molecular cytogenetic identification was carried out by GISH,FISH,PMC MI,SSR,SDS-PAGE and combined with agronomic traits and disease resistance identification.The main results are as follows:1.The meiotic behaviors of the 4 wheat-E.repens derivatives translocation lines come as follow:K15-1194-2,2n=42=2.45 ?+ 14.17 ?(ring)+ 5.50 ?(rod)+ 0.07 ?;K15-1192-2,2n=42=0.87 ?+ 17.46 ?(ring)+ 3.11 ?(rod);K15-1155-6,2n=42=0.83 I+ 18.49 ?(ring)+ 2.10 ?(rod);K15-1211-1,2n=42=0.94 ?+ 16.90 ?(ring)+ 3.58?(rod)+ 0.03 ?.The K15-1155-6 and K15-1192-2 had normal chromosome pairing with rare univalents,no multivalents,suggested that K15-1155-6 and K15-1192-2 were cytologically stable;However,The K15-1194-2 and K15-1211-1 had normal chromosome pairing with a few univalents and multivalents,and cytology stability were relatively poor.2.GISH,FISH and molecular markers revealled that K15-1192-2 and K15-1155-6 showed 40 intact wheat chromosomes plus a pair of 3D wheat chromosomes with double terminal translocations;K15-1194-2 showed 39 intact wheat chromosomes plus a pair of 7DS Robertsonian translocation chromosomes and one translocated wheat chromosome with double terminal translocations;K15-1211-1 showed 41 intact wheat chromosomes plus one 3D wheat chromosome with double terminal translocations.Besides,the four materials of the translocation fragments were derived from the St genome.3.SDS-PAGE analysis showed that there were some differences in HMW-GS region with parents.Among them,there were three materials had some new bands in the HMW-GS region.Besides,the four materials all contained the 5 + 10 subunits.4.Compared with their parents,there were some significant differences in spike length,spikelet number,thousand-kernel weight and seed setting rate.The plant height of K15-1194-2 and K15-1192-2 were significantly higher than their parents.And tillering of K15-1194-2 and K15-1211-1 were significantly higher than P1142-3-1-4,CN16 and SM51.In addition,K15-1194-2,K15-1211-1 were susceptible to stripe rust,showing infection of types 3;K15-1192-2,K15-1155-6,P1142-3-1-4 were moderately resistant to stripe rust,showing 2 infection types.