A study was conducted to determine the number and chromosomal location
of quantitative trait loci (QTL) influencing the concentration of fiv
e fatty acids in 200 F2S1 lines derived from an Illinois High Oil (IHO
) by Illinois Low Oil (Early Maturity) (ILO(EM)) cross. Restriction fr
agment length polymorphism (RFLP) analysis was performed on the 200 S-
1 lines and concentrations of palmitic (16:0), stearic (18:0), oleic (
18:1), linoleic (18:2), and linolenic (18:3) acids were determined in
self-pollinated kernels harvested from plants grown in replicated fiel
d trials during 1992 and 1993. A series of 74 cDNA and genomic clones
were used and these revealed 80 polymorphic loci spaced, on average, 2
4 cM apart throughout the maize genome. Analysis of variance detected
significant (p < 0.05) associations between several RFLP loci and the
concentration of each fatty acid. A total of 15 RFLP loci clustered in
12 chromosomal regions were associated with the concentration of 16:0
, 17 loci clustered in 10 regions were associated with the concentrati
on of 18:0, 12 loci clustered in eight regions were associated with th
e concentration of 18:1 and 18:2, and 17 loci clustered in eight regio
ns were associated with the concentration of 18:3. Multiple linear reg
ression models consisting of four RFLP loci explained 24 and 62% of th
e total phenotypic and genotypic variation (R(2)) among the 200 F2S1 l
ines for 16:0, five loci explained 51 and 71% of the variation for 18:
0, three loci explained 67 and 79% of the variation for 18:1, two loci
explained 67 and 81% of the variation for 18:2, and seven loci explai
ned 52 and 78% of the variation for 18:3 in these 200 F2S1 lines. The
ratio of 18:1 to 18:2 was tightly interrelated as the same QTL were as
sociated with the concentrations of 18:1 and 18:2. A quantitative trai
t locus that explained 63% of the phenotypic variation in the ratio of
18:1 to 18:2 is tightly linked to umc65 on chromosome 6 in the region
of the linoleic acidl locus.