Response of recurrent selection on yield, kernel oil content and fatty acid composition of subtropical maize populations

Abstract

High oil maize (HOM) has been successfully achieved by a long-term breeding program. The aim of this study was to evaluate eight cycles of recurrent selection for agronomic traits and HOM content in four subtropical white and yellow maize populations and the effect of selection on yield, kernel physical properties, oil content, fatty acid (FA) profile and lipophilic antioxidant (LAOX) capacity. Through the selection cycles the agronomic traits showed a low but significant increase of grain yield and reduction in diseases. These positive changes significantly affected kernel physical properties and distribution of ground particles related to grain hardness. Oil content in kernels increased through cycles of selection and had a positive correlation (r<0.001) with the germ size. The improved kernels belonging to the last cycles contained from 33 to 60% more oil compared to original counterparts. Oleic acid (OLA) and linoleic acid (LOA) accounted for approximately 79–85% of total FA and the relative proportions of these FA slightly decreased during selection. The percentage of Ω-3 linolenic acid increased in the oil belonging to the advanced HOM populations whereas LAOX significantly decreased with cycles of selection. There was not a relationship between the observed oil increase with grain yield; however, the monounsaturated oleic proportion tended to decrease in kernels belonging to the yellow populations. Fatty acids and LAOX capacity had a positive correlation with OLA and negative (r>0.65) with LOA. This research demonstrated that it was feasible to develop high-yielding subtropical populations with HOM content and acceptable agronomic performance and grain physical properties.