| In recent years,the area of high-yield and high-quality wheat varieties in China has gradually expanded,while the severity of wheat FHB and stripe rust has also been on the rise.Thinopyrum,as a related species of wheat,has good resistance to FHB and stripe rust due to its long-term natural selection,Therefore,further strengthening the utilization of the disease-resistance genes in Thinopyrum is of great significance for breeding new wheat varieties with resistance to stripe rust and FHB.Additionally,traditional breeding methods are cumbersome,time-consuming,and slow in developing varieties,but the combination of haploid technique and traditional strategies can effectively solve this problem.The objectives of this study are to improve the disease resistance of two spring wheat varieties Ningchun4 and Ningchun50 through backcross breeding by using two translocation materials WT15 and Y7698 which are resistant to stripe rust and FHB,respectively,and to induce haploid production of an offspring line WB34-3 between Ningchun4 and WT15 by using the haploid inducer containing visual markers as the male parent for fast breeding.The main results achieved in this study are presented as follows.1.By using Ningchun4 as recurrent parent,and wheat-Thinopyrum intermedium translocation line WT15 and wheat-Thinopyrum elongatum translocation line Y7698,respectively,two BC1F2 populations WB34-3 and YB34-3,and two BC3 population WB34-2 and YB34-2 were obtained.Detections of specific molecular markers specific to the target chromosome fragments of Th.intermedium and Th.elongatum and genomic in situ hybridization using the total DNAs of Th.intermedium and Th.elongatum as probes revealed that WB34-3 and WB34-2 contained Th.intermedium chromosome fragment,and YB34-3 and YB34-2 contained Th.elongatum chromosome fragment,in which WB34-3 carried one translocation chromosome,and YB34-3 carried two translocation chromosomes.Stripe rust resistance test by inoculating the mixed spores of the races CYR32,CYR33 and CYR34 showed that WB34-2 was high resistant to the disease.Investigation on the agronomic traits of the BC3 materials and Ningchun4 indicated that WB34-2 and YB34-2 were slight different from their recurrent parent Ningchun4.2.By using Ningchun50 as recurrent parent,and WT15 and Y7698 as the donors of strip use and FHB,Two BC1F2 populations WB35-3 and YB35-3,and two BC3 populations WB35-2 and YB35-2 were obtained.After molecular marker detection,stripe rust resistance test,genomic in situ hybridization identification,and agronomic character investigation,WB35-3 and WB35-2 were confirmed to be wheat-Th.intermedium translocation materials,YB35-3 and YB35-2 to be wheat-Th.elongatum translocation lines,in which WB35-3 contained two translocation chromosomes,and YB35-3 contained one translocation chromosome;WB35-2 showed high resistance to stripe rust;there were still some differences between WB35-2 and YB35-2 and Ningchun50 in main agronomic traits.3.After a haploid inducer line HIPE(haploid inducer with purple embryo)containing ZmR and ZmC1 genes as well as the edited TaMTL-ABD loci was crossed as the male parent with the progeny WB34-3 from the hybrid combination of wheat-Th.intermedium translocation line WT15 and Ningchun4,F1 grains were produced.By observing the embryo color of the hybrid grains,haploid grains were primarily screened out,and the haploid seedlings germinated from the candidate haploid grains were further confirmed by chromosomes counting at root tips,guard cell length on leaves,and flow cytometry of DNA content in tissues. |
