甘蓝型春油菜早花位点加密及位点聚合创建优异早花资源

Locus encryption for early flowering and QTL polymerization to create excellent early flowering resources of spring Brassica napus L.

cqDTFA7a and cqDTFC8, two major effects of early flowering QTL, were identified in the NNDH population of spring Brassica napus, and closely linked markers SSR G1803, InDel IA7-4, and SSR S035 with cqDTFC8 developed in previous studies. In this study, a BC₂F₂ population for early flowering QTL locus cqDTFC8 was constructed, and a closely linked SNP marker was further developed. The early flowering genotypes of one natural resources contained 93 spring B. napus varieties were identified used four closely linked markers with two loci, and selected 3164 and 2216 resources with cqDTFA7a site, 3484 and 2857 resources with cqDTFC8 site. Two site resources were aggregated by site polymerization through reciprocal hybridization. The polymerized DH system was rapidly obtained by microspore culture and maker assisted selection. A hybrid combination was created between polymeric line with good traits and early flowers and the Polima CMS, and the utilization value of the polymeric line was further analyzed by the production test at multiple environments for two consecutive years. cqDTFC8 encryption results showed that this site was located in the SNP11 and SNP12 interval, and separated from SNP11 altogether. The identification results of early flowering genotypes of natural resources showed that there were 50 individuals containing cqDTFA7a locus, with an average initial flowering period of 58.1 days; 16 single plants containing cqDTFC8 locus, with an average flowering period of 58.3 days; and 16 single plants containing two loci, with an average flowering period of 55.2 days, indicating the more early flowering sites containing, the earlier flowering. The results of polymerization showed that the flowering time of the polymerized lines of cqDTFC8 and cqDTFA7a was 2-3 days earlier than that of the single locus parents, among which the polymerized DH18 from 3164 of cqDTFA7a and 3484 of cqDTFC8 was 3 days earlier than that of the parents, and the yield-related traits were better than those of other lines. The combination of DH18 and the Polima CMS 025A was further utilized, and the combination was named TZG18. Yield results of two years and nine environments showed that yield of TZG18 was above 17.5% higher than the Haoyou 11, a local B. rapa variety on the Qinghai-Tibet plateau. Those results indicated that the early flowering site polymeric lines had an obvious advantage over the single locus lines in flowering time, and had an effect on the increasement of rapeseed yield. This study is a preliminary exploration of MAS breeding for early flowering traits of Brassica napus, providing materials support for replacing B.rapa varieties using early maturity Brassica napus varieties in spring rapeseed region, and approaches for gene polymerization breeding technology.