Location of chromosomal regions controlling fatty acid composition of embryo oil in Zea mays L.

Abstract

B–A translocations were utilized in Zea mays L. to assign regions affecting the fatty acid composition of embryo oil to chromosome arms. A region affecting all four measured fatty acids (palmitic, stearic, oleic, and linoleic acids) was assigned to the long arm of chromosome 4 by results of tests with TB-4Lb, whereas another affecting palmitic and stearic acids was assigned to the long arm of chromosome 10 by tests with TB-10L19. These effects were in agreement with previous results from analysis of trisomy for chromosome 4 and monosomy for chromosome 10. The fatty acid composition of euploid embryos containing a B chromosome was not significantly different from that of embryos not containing a B chromosome. Thus, the B chromosome is not responsible for the differences observed using B–A translocations. TB-5La was backcrossed into two inbred lines having a relatively high percentage of linoleic acid. Hyperploidy for the long arm of chromosome 5 significantly increased the percentage of linoleic acid in both inbreds. Aneuploidy for the long arm of chromosome 5 also had a dosage effect on fatty acid composition of the endosperm.Key words: Zea, corn oil, fatty acids, B chromosome, translocation.