QTL for Fatty Acid Composition of Maize Kernel Oil in Illinois High Oil × B73 Backcross‐Derived Lines

Abstract

Maize (Zea mays L.) produces high‐quality oil valued for oxidative stability and low concentrations of saturated fatty acids. The nutritional value of maize oil could be improved by increasing the concentration of oleic acid, a “heart‐friendly” monounsaturated fatty acid. To identify quantitative trait loci (QTL) for the major fatty acids constituting oil from maize kernels, we produced 150 backcross1‐derived S1 (BC1S1) lines from donor parent, Illinois High Oil (IHO), and recurrent parent, B73. There was a positive phenotypic correlation between oil and oleic acid (rp = 0.47**, α ≤ 0.01) and negative correlations between oil and linoleic acid (rp = −0.46**), and between oleic and linoleic acids (rp = −0.99**). Multiple regression models with QTL detected by composite interval mapping (CIM) on a genetic map with length = 1486 cM, explained 15.4, 41.6, 51.0, 59.6, and 47.9% of the phenotypic variation for palmitic, stearic, oleic, linoleic, and linolenic acids, respectively. A 6‐cM interval on chromosome 6 (bin 6.04) includes QTL for stearic, oleic, linoleic, and linolenic acids, explains 10.9 to 39.6% of the variation for these fatty acids, and is 10 to 16 cM from QTL for oil. Another region on chromosome 6 (bin 6.01) includes QTL for oleic and linoleic acids and was epistatic with the QTL in bin 6.04. One or both of these two QTL regions on chromosome 6 may be responsible for fatty acid variation previously attributed to linoleic acid1