Molecular Marker And Pyramiding Of Multilocular?Self-compatibility And Clubroot Resistance Gene In Chinese Cabbage

Application of molecular marker assisted selection in crop variety improvement is very general.The technique were used combined with molecular marker identification,which can be used in the early stage of breeding to achieve the purpose of rapid and effective Pyramiding of multiple genes.To creat high quality germplasm for Chinese cabbage breeding and gain fine breeding maintainer,Pyramiding of the self-compatibility and multilocular gene in yellow sarson lines of Brassica rapa with clubroot resistant CRb gene of Chinese cabbage was carried through molecular marker assisted selection.The main results showed as follows:1.Genetic analysis of self-compatibility locular number traits of F1 and F2 generations were carried out by means of self-compatibility and self-incompatibility of Brassica rapa.The results suggest that the F1 generation of both positive and negative crosses were self-incompatible and bilocular,and F2 generation occured to character segregation.The fitness test showed that the separation of self-incompatibility and self-compatible plants in F2 generation group was in accordance with the separation ratio of 3:1.The inheritance of multilocular trait was the same as it.The results showed that self-compatibility and multilocular traits were controlled by a pair of recessive genes.2.In this experiment,we designed the SSR markers related to the multilocular traits,and obtained a pair of molecular markers,Teo-1 was closely linked to multilocular by polymorphism screening.Co-segregation Verification was carried out to test whether the newly developed markers Teo-1 was linked to multilocular trait,The results showed that the results were consistent with the results of phenotypic identification.3.Polymorphism screening of 8 pairs and self-compatible markers was carried out,we obtained three dominant markers PK1+PK4,Sal-SLGI and Sal-SRK I,in which marker PK1+PK4 was closely linked to self-compatibility and marker Sal-SLG I and Sal-SRK I were closely linked to self-incompatible.In order to distinguish the heterozygous individuals in the heterozygous individuals,a pair of co-dominant marker PK1+PK4/Sal-SLG I was developed by using multiple PCR technique.Co-segregation Verification was carried out to test whether the newly developed markers PK1+PK4/Sal-SLGI was linked to self-compatibility trait,The results showed that the results were consistent with the results of phenotypic identification.4.Two flanking markers sau_um 190 and cun₂46a and marker Teo-1 based on the gene sequence were used to select the multilocular trait.Two flanking markers SCF-6 and SC-12 and marker Sal-SLG I/PK1+PK4 based on the gene sequence were used to select the self-compatibility trait.Two flanking markers TCR74 and TCR79 closely linked to clubroot resistance gene CRb were used as foreground selection marker.Background selection marker were 111 Chinese cabbage genome markers covering 10 chromosomes.All the above maarkers were used to create pyramiding lines of self-compatibility gene,multilocular gene and clubroot resistance gene CRb,through five generations selectting.The genetic background recovery rate of the multi-gene pyramiding lines did not reach the expected value,it needs continue to select in the next generation.