BackgroundInBrachiariasexual reproduction, during ovule development, a nucellar cell differentiates into a megaspore mother cell (MMC) that, through meiosis and mitosis, gives rise to a reduced embryo sac. In aposporic apomicticBrachiaria, next to the MMC, other nucellar cells differentiate into aposporic initials that enter mitosis directly forming an unreduced embryo sac. TheIPT(isopentenyltransferase) family comprises key genes in the cytokinin (CK) pathway which are expressed in Arabidopsis during ovule development.BbrizIPT9, aB. brizantha(syn. Urochloa brizantha)IPT9gene, highly similar to genes of other Poaceae plants, also shows similarity with ArabidopsisIPT9, AtIPT9.In this work, we aimed to investigate association ofBbrizIPT9with ovule development in sexual and apomictic plants.Methods and resultsRT-qPCR showed higherBbrizIPT9expression in the ovaries of sexual than in the apomicticB. brizantha. Results of in-situ hybridization showed strong signal ofBbrizIPT9in the MMC of both plants, at the onset of megasporogenesis. By analyzingAtIPT9knockdown mutants, we verified enlarged nucellar cell, next to the MMC, in a percentage significantly higher than in the wild type, suggesting that knockout ofAtIPT9gene triggered the differentiation of extra MMC-like cells.ConclusionsOur results indicate thatAtIPT9might be involved in the proper differentiation of a single MMC during ovule development. The expression of aBbrizIPT9, localized in male and female sporocytes, and lower in apomicts than in sexuals, and effect ofIPT9knockout in Arabidopsis, suggest involvement ofIPT9in early ovule development.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11033-023-08295-7.