You are using an outdated browser. This page doesn't support Internet Explorer 6, 7 and 8.Please upgrade your browser or activate Google Chrome Frame to improve your experience. Maize is an important food and feed crop in many countries. It is also one of the most important target crops for the application of biotechnology. Currently, there are more biotech traits available on the market in maize than in any other crop. Generation of transgenic events is a crucial step in the development of biotech traits. For commercial applications, a high throughput transformation system producing a large number of high quality events in an elite genetic background is highly desirable. There has been tremendous progress in Agrobacterium-mediated maize transformation since the publication of the Ishida et al. (1996) paper and the technology has been widely adopted for transgenic event production by many labs around the world. We will review general efforts in establishing efficient maize transformation technologies useful for transgenic event production in trait research and development. The review will also discuss transformation systems used for generating commercial maize trait events currently on the market. As the number of traits is increasing steadily and two or more modes of action are used to control key pests, new tools are needed to efficiently transform vectors containing multiple trait genes. We will review general guidelines for assembling binary vectors for commercial transformation. Approaches to increase transformation efficiency and gene expression of large gene stack vectors will be discussed. Finally, recent studies of targeted genome modification and transgene insertion using different site-directed nuclease technologies will be reviewed. Keywords: maize transformation, Agrobacterium, T-DNA, transgenic events, multi-gene stack, trait development, genome modification, targeted insertion Citation: Que Q, Elumalai S, Li X, Zhong H, Nalapalli S, Schweiner M, Fei X, Nuccio M, Kelliher T, Gu W, Chen Z and Chilton M-DM (2014) Maize transformation technology development for commercial event generation. Front. Plant Sci. 5:379. doi: 10.3389/fpls.2014.00379 Copyright © 2014 Que, Elumalai, Li, Zhong, Nalapalli, Schweiner, Fei, Nuccio, Kelliher, Gu, Chen and Chilton. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. *Correspondence: Qiudeng Que, Syngenta Biotechnology, Inc., 3054 E. Cornwallis Road, PO Box 12257, Research Triangle Park, NC 27709-2257, USA e-mail: email@example.com Source.