Development And Identification Of Wheate-Lymus Repens Translocation Lines With Resistance To Fusarium Head Blight

Elymus repens(L.)Gould(2n = 6x = 42,St St St St HH),is a tertiary gene pool of wheat.It has many excellent traits such as resistance to biotic stress(Fusarium head blight,stripe rust,etc.)and abiotic stress(drought tolerant,cold resistant,etc.),thus,it is taken as a valuable genetic resource pool for wheat genetic improvement.Based on distant hybridization and chromosome engineering techniques,excellent genes from E.repens could be transferred into common wheat to broaden the genetic background of wheat,innovate wheat germplasm,and improve wheat resistance to Fusarium head blight.In this study,common wheat Crocus,seven Sichuan bred wheat varieties and wheat-E.repens partial diploid P1142-1-2-1(2n = 8x = 56,AABBDDSt H)were conducted for multiparent hybridization and backcrosses,and wheat-E.repens lines containing E.repens chromosomes were screened from the selfed progeny by genomic in situ hybridization(GISH).With Sumai 3 and PH691 as controls for Fusarium head blight(FHB),the resistance to FHB in the wheat-E.repens derived lines were determined in both fields and greenhouses,afterward the homology chromosome group with FHB-resistant was identified.The main research results are as follows:1.240 wheat-E.repens derived progeny materials were identified and screened by GISH.In total,43 of them carried 1-8 alien chromosomes and/or fragments,in which 30 materials were St chromosomes translocation lines,9 plants were addition lines,and 4 specimens carry St chromosome translocation fragments and the entire St chromosome.The St chromosome fragments varied from 1 to 8,and additional entire St chromosome varied from 1～3.2.To investigate the FHB-resistance in field,single strain PH-1 was inoculated into progenies above,wheat-E.repens derived lines created by the research group and relative parents using the single flower drip injection method.The results showed that seven common wheat parents were highly susceptible to FHB,whereas the parent P1142-1-2-1 showed FHB resistance.In total,50 of them exhibited excellent FHB resistance,such as K22-C6,K22-C30,and K22-C159.Eight materials were randomly selected for chromosome constitute identification,we found that all materials contained one or two St chromosome telomere(s)or centromere translocations from E.repens.3.To investigate the FHB-resistance in green house,the hybrid and inbred progenies of above 8 materials were inoculated with the mixture of six dominant FHB races in Sichuan Province.We found that K22-C159-6,a inbred plant from K22-C159,was resistant to all mixed dominant races.Genome constitution results revealed the four inbred progenies of K22-C159-6 with 2n=42W+2St-W-St(W: chromosome of common wheat),which was a wheat-E.repens double-end translocation line,moreover,those progenies exhibited excellent FHB resistance to mixed races.Based on the 1St-7St chromosome-specific molecular marker developed by our group,we identified that the St chromosome fragment in K22-C159-6originated from the 3St chromosome of E.repens.In summary,the wheat-E.repens translocation line with resistance to FHB developed in this study as an intermediate material,which offers new resistant germplasm and genetic resources for wheat breeding in Sichuan.