Genetics, Vol. 177, 2433-2444, December 2007, Copyright © 2007
doi:10.1534/genetics.107.080705

Flowering Time Quantitative Trait Loci Analysis of Oilseed Brassica in Multiple Environments and Genomewide Alignment with Arabidopsis

Y. Long*, J. Shi*, D. Qiu*, R. Li*, C. Zhang*, J. Wang*, J. Hou*, J. Zhao*, L. Shi*, Beom-Seok Park{dagger}, S. R. Choi{ddagger}, Y. P. Lim{ddagger} and J. Meng*,1

* National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China, {dagger} Brassica Genomics Team, National Institute of Agricultural Biotechnology, Rural Development Administration, Suwon 441-707, Republic of Korea and {ddagger} Department of Horticulture, Genome Research Institute, Chungnam National University, Daejeon 305-764, Republic of Korea

1 Corresponding author: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
E-mail: jmeng{at}mail.hzau.edu.cn

Most agronomical traits exhibit quantitative variation, which is controlled by multiple genes and are environmentally dependent. To study the genetic variation of flowering time in Brassica napus, a DH population and its derived reconstructed F2 population were planted in 11 field environments. The flowering time varied greatly with environments; 60% of the phenotypic variation was attributed to genetic effects. Five to 18 QTL at a statistically significant level (SL-QTL) were detected in each environment and, on average, two new SL-QTL were discovered with each added environment. Another type of QTL, micro-real QTL (MR-QTL), was detected repeatedly from at least 2 of the 11 environments; resulting in a total of 36 SL-QTL and 6 MR-QTL. Sixty-three interacting pairs of loci were found; 50% of them were involved in QTL. Hundreds of floral transition genes in Arabidopsis were aligned with the linkage map of B. napus by in silico mapping; 28% of them aligned with QTL regions and 9% were consistent with interacting loci. One locus, BnFLC10, in N10 and a QTL cluster in N16 were specific to spring- and winter-cropped environments respectively. The number of QTL, interacting loci, and aligned functional genes revealed a complex genetic network controlling flowering time in B. napus.