Major and Minor QTL as well as Epistasis all Contribute to Oil Synthesis and
Accumulation in High-oil Maize
Xiao-Hong Yang1, Yu-Qiu Guo1, Jian-Bing Yan1, Jun Zhang1, Yi-Rong Zhang1, Torbert Rocheford2 and
Jian-Sheng Li1*
1
National Maize Improvement Center of China, China Agricultural University, Beijing 100094, China
2
Department of Crop Sciences, University of Illinois, 1102 S. Goodwin Ave, Urbana, IL 61801, USA
*
corresponding author, lijiansheng@cau.edu.cn
High-oil maize developed by long-term selection is a unique genetic resource for
genomic investigation in plants. To exploit the genetic basis of high-oil maize, a
recombinant inbred (RIL) population derived from a single cross between normal line
B73 and high oil line By804 was employed. Two-hundred and forty-five RILs were
phenotyped for fatty acid compositions and oil concentration by gas chromatography
and genotyped using 202 SSR, 6 IDP and 20 candidate gene-related markers. A total
of 44 individual QTL and 22 pairs of epistatic QTL controlling fatty acid
compositions and oil concentration were detected by QTLNetwork 2.0. The highest
individual additive effect explained 45.5% of phenotypic variance (palmitic acid, 16:0)
and the highest epistatic effect explained 4.0% of phenotypic variance (oil). On
average, the percentage of total phenotypic variance explained by additive and
epistatic effects for all traits was 56.0% and 6.5%, respectively. Three Loci on
chromosomes 1 (bin 1.04), 6 (bin 6.04) and 9 (bin 9.02) were detected to contain five
major QTL for palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2) acid and oil
concentration. Each of them explained 45.5%, 22.4%, 27.1%, 19.1% and 15.9% of
phenotypic variance among RIL population, respectively. These results demonstrated
that a few individual major QTL with large effect, together with many individual and
epistatic QTL with small effect all contribute to the oil synthesis and accumulation in
high-oil maize.