_____________________________________________________________________________________________________ *Corresponding author: E-mail: ahmedmedhatalnaggar@gmail.com, medhatalnaggar@gmail.com; Journal of Applied Life Sciences International 5(4): 1-18, 2016; Article no.JALSI.26811 ISSN: 2394-1103 SCIENCEDOMAIN international www.sciencedomain.org Maximizing Maize (Zea mays L.) Crop Yield via Matching the Appropriate Genotype with the Optimum Plant Density A. M. M. Al-Naggar 1* , M. M. M. Atta 1 , M. A. Ahmed 2 and A. S. M. Younis 2 1 Department of Agronomy, Faculty of Agriculture, Cairo University, Giza, Egypt. 2 Department of Field Crops Research, National Research Centre (NRC), Dokki, Giza, Egypt. Authors’ contributions This work was carried out in collaboration between all authors. Author AMMAN designed the study, wrote the protocol and wrote the first draft of the manuscript. Authors MMMA and MAA managed the literature searches. Author ASMY managed the experimental process and performed data analysis. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JALSI/2016/26811 Editor(s): (1) Shahira M. Ezzat, Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Egypt. (2) Muhammad Kasib Khan, Department of Parasitology, University of Agriculture, Pakistan. Reviewers: (1) T. A. Mtaita, Africa University, Mutare, Zimbabwe. (2) Muhammad Shehzad, The University of Poonch Rawalakot, AJK, Pakistan. (3) Simic Milena, Maize Research Institute Zemun Polje, Belgrade, Serbia. Complete Peer review History: http://sciencedomain.org/review-history/14904 Received 3 rd May 2016 Accepted 31 st May 2016 Published 4 th June 2016 ABSTRACT Aim: The objective of this investigation was to match the functions of optimum plant density to produce the highest possible grain yield per unit area with the greatest maize genotype efficiency. Study Design: A split plot design in randomized complete block arrangement was used with three replications. The main plots were assigned to plant densities, and sub-plots to maize genotypes. Place and Duration of Study: This study was carried out at the Agricultural Experiment and Research Station of the Faculty of Agriculture, Cairo University, Giza, Egypt in 2012, 2013 and 2014 seasons. Methodology: Six maize inbred lines differing in tolerance to high density (D) [three tolerant (T); L- 20, L-53, Sk-5, and three sensitive (S); L-18, L-28, Sd-7] were chosen for diallel crosses. Parents and hybrids were evaluated under three plant densities: low (47,600), medium (71,400), and high (95,200) plants ha -1 . Original Research Article