Research Article Genetic Variability and Selection Criteria in Rice Mutant Lines as Revealed by Quantitative Traits Yusuff Oladosu, 1 M. Y. Rafii, 1,2 Norhani Abdullah, 1,3 Mohammad Abdul Malek, 1,4 H. A. Rahim, 5 Ghazali Hussin, 6 Mohammad Abdul Latif, 2,7 and Isiaka Kareem 1 1 Institute of Tropical Agriculture, Universiti Putra Malaysia (UPM), Serdang, 43400 Selangor, Malaysia 2 Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia (UPM), Serdang, 43400 Selangor, Malaysia 3 Department of Biochemistry, Faculty of Biotechnology and Biomolecular Science, Universiti Putra Malaysia (UPM), Serdang, 43400 Selangor, Malaysia 4 Bangladesh Institute of Nuclear Agriculture, Mymensingh 2202, Bangladesh 5 Bioscience and Agrotechnology Division, Malaysian Nuclear Agency, Bangi, 43000 Selangor, Malaysia 6 Strategic Livestock Research Centre, Malaysian Agricultural Research and Development Institute (MARDI), Serdang, 43400 Selangor, Malaysia 7 Bangladesh Rice Research Institute (BRRI), Gazipur, Bangladesh Correspondence should be addressed to M. Y. Rafi; mrafi@upm.edu.my Received 5 July 2014; Revised 8 September 2014; Accepted 8 September 2014; Published 5 November 2014 Academic Editor: Jean Louis Hilbert Copyright © 2014 Yusuf Oladosu et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Genetic based knowledge of diferent vegetative and yield traits play a major role in varietal improvement of rice. Genetic variation gives room for recombinants which are essential for the development of a new variety in any crop. Based on this background, this work was carried out to evaluate genetic diversity of derived mutant lines and establish relationships between their yield and yield components using multivariate analysis. To achieve this objective, two feld trials were carried out on 45 mutant rice genotypes to evaluate their growth and yield traits. Data were taken on vegetative traits and yield and its components, while genotypic and phenotypic coefcients, variance components, expected genetic advance, and heritability were calculated. All the genotypes showed variations for vegetative traits and yield and its components. Also, there was positive relationship between the quantitative traits and the fnal yield with the exception of number of tillers. Finally, the evaluated genotypes were grouped into fve major clusters based on the assessed traits with the aid of UPGMA dendrogram. So hybridization of group I with group V or group VI could be used to attain higher heterosis or vigour among the genotypes. Also, this evaluation could be useful in developing reliable selection indices for important agronomic traits in rice. 1. Introduction Rice (Oryza sativa) is an important staple food in the world. Despite its position among the highly rated cereals, it feeds more than half of the world’s population. Te geometric growth rate of the global population has called for yield improvement of this very important cereal. On this, sev- eral methods have been tried by scientists to combat this perennial problem. Some researchers have tried nutritional method, physiological method, and breeding as well as control of pests and diseases. Among these methods, it is established that breeding for high yield traits is the most sustainable because the traits are heritable. To achieve this breeding objective, changes at cellular level are employed to get traits that could improve yield. Tese changes are referred to as mutations and may occur either in the genes or at chromosomal level to bring the desired improvement. At present, improvement of major food crops in the world rests majorly on mutation. Tis comes either naturally or through irradiation. So crops with restriction in genetic variation require mutagenesis or induced mutation to create desirable and heritable variations in them [1]. Following this, the use of induced mutations has been extensively used for genetic enhancement of diferent crops [2, 3]. Ionizing radiation of Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 190531, 12 pages http://dx.doi.org/10.1155/2014/190531