Study On Heterosis And Identification Of Seed Purity Of Male Sterile Lines Of Chinese Cabbage

Chinese cabbage is the main vegetable crop in China.It is of great significance to study the combining ability of male sterile lines in Chinese cabbage for the application of heterosis and improving the level of Chinese cabbage breeding.Rapid and accurate identification of seed purity of excellent Chinese cabbage hybrids can speed up the promotion time of new Chinese cabbage varieties.Based on the comparative observation of 4 male sterile lines and their maintainer lines of Chinese cabbage,the heterosis of 60 F₁ hybrids was analyzed,and the DNA fingerprints of 21 parents of Chinese cabbage were constructed by SSR molecular markers.Finally,SSR molecular marker technology was used to identify the seed purity of new F₁ hybrid’shaanqiubai 2’of Chinese Cabbage.The main results are as follows:1.The results showed that the male sterile line had no pollen,the anther was withered,the filament was short,the pollen of the maintainer line was normal,and the stamens were long.Through the identification of sterile genes of four male sterile lines 18BC22,18BC23,18BC26 and 18BC35,18BC35 is Ogu CMS type,and 18BC22,18BC23 and 18BC26 all contain orf138 and orf222 genes,which are referred to as Ogu-nap CMS type.2.The general combining ability of 14 agronomic characters of 21 excellent male sterile lines and inbred lines of Chinese cabbage and the special combining ability of 60 F₁ hybrid combinations were determined.Three hybrid combinations with better combining ability were screened,which were 20DF47（18BC35×19H33）、20DF50（18BC35×19S463）、20DF53（18BC35×19S197）.According to cluster analysis,21 overlapping Chinese cabbage lines were divided into four groups.The first group has 19H33,91-125,19S575,06J31,19S500,19H72 and 19S470,the second group has 19S197 and 19S115,and the third group included 19S281,19S171,19S122,17S64,19S59,15S1080,the fourth group included19S405,18BC26,18BC34,19S463,18BC23 and 18BC22.3.The fingerprints of 21 overlapped Chinese cabbage male sterile lines and inbred lines were constructed,which can accurately distinguish 21 overlapped Chinese cabbage inbred lines each other.4.Three pairs of SSR primers,SSRA02-2,SSRA08-1 and SSRA08-3,which can quickly and accurately identify the seed purity of the excellent Hybrid’shaanqiubai 2’,were screened out.The identification results of the seed purity of’shaanqiubai 2’are consistent with those of the field,which accelerates the cycle of seed purity identification of Chinese cabbage and is of great significance to the promotion of new varieties.