Using Molecular Markers To Create Brassica Juncea Resources Containing Brassica Rapa Genes

Mustard(2n=36,Brassica juncea)is an important processed and fresh vegetable in China.Among them,because of its easy cultivation and short growth cycle,the planting area of Brassica juncea var.capitata Hort in leaf mustard(Brassica juncea var.foliosa Bailey)has gradually expanded with the development of industrialized processing technology of pickled cabbage.At present,most of the mustard varieties cultivated in our country are local conventional varieties,which are too disorder to meet the needs of production and development.The traditional breeding selection is based on the individual’s phenotype in the field.This has a good effect on quality traits,but it has poor accuracy for quantitative traits.It is difficult to obtain the ideal material only through field selection.Molecular marker assisted selection can directly select genotypes,which is more accurate.The combination of the two can quickly obtain an ideal single plant.In this study,several different Brassica juncea and cabbage were used as parent materials,F1 was obtained by hybridization,BC1 was obtained by Backcross embryo culture.A group of HRM-InDel markers with good polymorphism and stability were developed by using the resequencing data of Chinese cabbage.The genetic background of Chinese cabbage in backcross population was screened and analyzed.The following conclusions are obtained:1.We obtained 9 interspecific hybrids and 14 BC1 populations by distant hybridization combined with immature embryo culture.The low fertility or sterility of hybrids is very practical in the hybrid identification of triploid F1.The fertility of triploid hybrid is low;BC1 of backcross generation is more difficult to obtain than F1 of hybrid generation.The average of seed setting rate of the combination of immature embryo culture was 4.72%,while the average of the combination without immature embryo culture was 2.9%.2.By screening the genome,I obtained 233 HRM-InDel markers evenly distributed on genome.The success rate of marker was 52.01%.Among them,57 pairs markers can be used to distinguish all cabbage and mustard,and 87 pairs can be used to distinguish the heading Chinese cabbage and non heading Chinese cabbage.The results of marker screening showed that the cabbage B9008 was similar to the mustard in terms of its nodularity traits.Using HRM typing,B9008 and mustard was classified into the same group.It was considered that it had a close relationship with cabbage,and it was an ideal material for improving its nodularity.3.In this study,the ideal hybrid combination and single hybrid plant were obtained,and the backcross progeny tended to contain cabbage gene.Among the 14 BC1 populations,the selected hybrid combination of YZ17JC175 X B9008 has the most individual plants with the tendency to heading cabbage,which is an ideal material for improving heading breeding.The backcross compatibility was poor when Chiifu was the male parent,and the offspring contained less cabbage genes,which indicated that Chiifu was not an ideal material to enrich mustard resources.Twenty InDel markers were used to trace the genes of 192 BC1 plants.Half of the single-plant marker content is above 78.3%,and 54 single-plant marker content exceeds 90%.Further research work has accumulated materials,which was beneficial to the creation of materials and accumulated materials for the further research.