Study On Diversity Of Chinese Cabbage Germplasm Resource And Heterosis Of Cannonball-shaped Chinese Cabbage And Purity Identification Of An Excellent Hybrids

Chinese cabbage is native to my country and is widely cultivated in my country.The study of heterosis and classification of groups is of great significance to promote the research of heterosis of Chinese cabbage and improve breeding efficiency.At the same time,the promotion of new varieties has clear requirements for seed purity,and rapid purity identification of excellent hybrids is of great significance to the promotion of new varieties.Based on the diversity analysis and group division of 65 Chinese cabbage inbred lines,this study adopted a half-rotation method to determine the combining ability and agronomic traits of 12 cannonball-type Chinese cabbage inbred lines and their hybrid combinations.The heterosis performance was analyzed,and the DNA fingerprints of 12 parental inbred lines were constructed using SSR markers.Finally,the molecular identification method for the purity of the excellent hybrid "15 Za 85" hybrid was carried out.The main results are as follows:1.The analysis of SSR marker diversity in 65 Chinese cabbage inbred lines showed that the Nei gene diversity index was 0.54 and the Shannon polymorphism index was 0.91,indicating that the tested materials have high genetic diversity.SSR molecular marker clustering divided 65 Chinese cabbage inbred lines into 5 groups.Among them,the SSR markers and 23 phenotypic traits of 37 Chinese cabbage inbred lines were clustered and the consistency was tested to be moderate(0.46).Based on the pedigree analysis of some materials,it was found that the pedigree based on SSR marker clustering Materials with the same source are classified into the same group,indicating that the SSR marker clustering results truly reflect the inheritance of the inherent genome of the germplasm resources.Materials with the same pedigree source can be clustered in the same group,which is useful for heterosis prediction and parental selection.Guiding significance.Agronomic traits are jointly determined by genetics and environment,and the information provided by phenotypic traits and molecular markers is different.Both should be considered in breeding practice.2.The general combining ability of 14 agronomic traits of 12 cannonball-type Chinese cabbage inbred lines and the special combining ability performance of 66 hybrid combinations were clarified,and 6 materials with better combining ability were selected,namely 18S71,18S121,18S421,18S460,18S469 and 18S501,in which 18S415 general combining ability is all negative,they are good materials for breeding small fast vegetables.According to the special combining ability of yield,12 inbred lines were divided into 3 groups.The first category includes 18S36,18S460,18S501,and 18S549,the second category includes 18S39,18S40,18S41,and 18S71,and the third category includes 18S121,18S415,18S421,and18S469.The analysis of heterosis found that there were obvious yield heterosis among the 12 parents.Six excellent combinations with higher yield and better disease resistance were screened out,namely A11(18S121×18S39)and A14(18S121×18S71),A22(18S421×18S39),A32(18S71×18S460),A35(18S460×18S421),A63(18S549×18S469).3.The DNA fingerprints of 12 cannonball-type Chinese cabbage inbred lines were constructed,which can effectively distinguish 12 Chinese cabbage inbred lines.4.The three primer pairs that can quickly identify the purity of "15 Za 85" seeds were selected as SSRA05-1,SSRA08-3,and SSRA09-3.The identification results are consistent with the field identification results.This method greatly shortens the purity of Chinese cabbage seeds.The identification cycle is of great significance to the promotion of new varieties.