Fine mapping of a minor QTL on chromosome 2 controlling flowering time in Brassica napus L

Brassica napus L. is the third most cultivated oil crop in the world. Flowering time is one of the important agronomic traits that affecting crop yield. In this study, we constructed an early flowering near-isogenic line (NIL) NZ-A2, by using an early flowering accession NO.2127 as donor parent and a late flowering accession ZY821 as recurrent parent. Two QTLs, qFTA2.1a and qFTA2.1b , were detected in the A02 chromosome of B. napus , which accounting for 25.4% and 49.1% of the total flowering time variations, respectively. Further fine mapping of the qFTA2.1a delimited it in a chromosome interval with a physic distance of 245 Kb, in which an important flowering gene BnaFT.A2 was identified. The NIL contained the qFTA2.1a locus flowered about 7 days earlier than the late flowering parent ZY821. Thus, this QTL is of great significant to B. napus breeding for varieties with superior maturity.