Romanian Biotechnological Letters Vol. 16, No. 4, 2011 Copyright © 2011 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER 6305 Evaluating genetic diversity of canola cultivars using morphological traits and molecular markers Received for publication, December 12, 2010 Accepted, July 15, 2011 ALI ASGHARI 1 , MAJID SHOKRPOUR 1 , HAMIREZA MOHAMMADDOUST CHAMANABAD 1 , OMID SOFALIAN 1 1 Agronomy and Plant Breeding Department, Agriculture Faculty, University of Mohaghegh Ardabili, Ardabil, Iran, pobox 179. ali_asgharii@yahoo.com , Tel: 00984515510167, *Fax: 00984515512902 Abstract This study was conducted to evaluate genetic diversity of canola cultivars using morphological traits and molecular markers. In this study, 18 spring and winter type cultivars were sown in randomized complete block design with 3 replications at research farm of Mohaghegh Ardabili University in 2007. In each replication at flowering stage, 5 plants were selected and leaf samples collected to DNA extraction for RAPD analysis and chlorophyll measurement. At maturity stage, in selected plants, also morphological traits were measured. Significant differences were observed among cultivars in all studied traits. Hyola401 and Ebonite cultivars had high yield, yield components and leaf chlorophyll. Using cluster analysis (UPGMA method), the 18 canola cultivars were categorized in 3 groups. Using RAPD data, Nei's average genetic diversity varied from 0.05 (Hyola308 cv) to 0.16 (PF/1045/91 cv). Mean of genetic variation within (H S ), Total (H T ) and degree of genetic differentiations (G ST ) were 0.12, 0.27 and 0.56, respectively. The results showed that high variation exists within and between cultivars. Keywords: Genetic diversity, Canola, Molecular markers, RAPD. Introduction Rapeseed (Brassica napus L.), the most important crop species of Brassica genus, having 40-45% oil in seeds and at least 46.5% protein, 3.5% fat and 0.35% phosphorus in the meal, is a valuable oil crop in oil industry and animal feed [1]. Also, this plant has a good adaptation to a wide range of climates. On a count of these reasons, in comparison to other oil plants, many studies are being run around the world for improving that. A main prerequisite of each breeding project is availability to genetic variation [2, 3]. Comprehensive information about genetic structure of populations may be obtained, if a study on genetic diversity was done by morphological, chromosomal, biochemical and molecular markers as complementary to each other [4, 5]. In recent years, DNA markers along to other markers have been well applied to identify genotypes and to assess genetic diversity. DNA markers reflect directly individual differences at the level of DNA molecules [6] and cover coding and none-coding regions of genome. They are not affected by environment, developmental stage, certain tissue and organ, and have high genomic frequency, high polymorphism and mostly a random genomic distribution [7, 8, 9]. RAPD markers may be used in genetic diversity studies, relationships and QTL tagging. Also, they quickly provide useful information around different parts of genome for polymorphism [10, 11, 12, 13]. Despite the many benefits, these markers are relatively low repeatable. However, their appropriate repeatability has been reported in oily Brassica species by SOMERS & al. [14]. KIMURA & al. [15] applied RAPD technique for estimating genetic diversity among 50 varieties of canola, including 13 varieties of Chinese, 26 Japanese and 11 varieties of Korean, European and Canadians. In this study, most varieties of Chinese and Japanese were