Effect of the application of plant hormones on the formation of parthenocarpic fruits and oil production in oil palm interspecific hybrids (Elaeis oleifera Cortes x Elaeis guineensis Jacq.)

Abstract

ABSTRACT Oil palm is the most important oil crop globally, accounting for almost 40% of fats and oil consumption worldwide. The OxG interspecific hybrid results from the crossing of African oil palm Elaeis guineensis Jacq. and the American oil palm Elaeis oleifera Cortes. It is a promising genotype for its high productivity, oil quality, and partial resistance to some diseases. These hybrids require assisted pollination, an activity that is time-consuming and expensive. Oil production in the OxG hybrids depends on the formation of normal (fertile) fruits and seedless (parthenocarpic) fruits. Thus, it is appealing to stimulate parthenocarpic fruits without assisted pollination. This research evaluated artificial methods of inducing parthenocarpy by applying plant hormones, and the effect on bunch formation and oil quality and its potential implementation at an industrial scale. The study was carried out in a 6-year-old hybrid (OxG) Coari x La Mé. The effects of the plant hormones indoleacetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), naphthalene acetic acid (NAA), and an ethylene precursor (ethephon) were evaluated. IAA and ethephon did not result in consistent bunch production of parthenocarpic fruits. The plants presented abnormal fruit growth, low-weight bunches, and high abortion rates. 2,4-D and NAA promoted proper parthenocarpic fruit development with oil-to-bunch (O/B) values similar to those obtained with assisted pollination. Thus, NAA and 2,4-D are an excellent alternative for oil production in the OxG hybrids that can be implemented in the African oil palm, with particular relevance that pollinators are endangered, and highly female genotypes are widely used.