ISSN No. (Print): 0975-1130 ISSN No. (Online): 2249-3239 Genotypic Variation and Heritability of Antioxidant related Traits in Wheat Landraces of Iran Ali Vosough*, Roza Ghouchani** and Armin Saed-Moucheshi*** *Department of Plant breeding, Kermanshah Branch, Islamic Azad University, Kermanshah, IRAN **Department of Biology, Islamic Azad University, Damghan Branch, Damghan, IRAN ***Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, IRAN (Corresponding author: Ali Vosough) (Received 12 May, 2015, Accepted 15 June, 2015) (Published by Research Trend, Website: www.researchtrend.net) ABSTRACT: In respect to the importance of genetic variation and resolution of population structure for crop improvement, this study were carried out to investigate the interrelationships of biochemical traits and the extent of genetic variation in wheat landrace varieties. The research work was conducted at the agricultural research station of Razi University, Kermanshah, Iran in 2013-2014 growing season. Twenty Iranian landraces of bread wheat (Triticum aestivum L.) were cultivated in a randomized complete block design with three replications. Biochemical and antioxidant related traits such as superoxide dismutase activity, peroxide activity, catalase activity, ascorbic peroxide activity, proline content, carotenoid content, hydrogen peroxide, and malondialdehyde content were measured in landraces. The overall results showed a high genotypic variation for enzymatic antioxidant activity, and also high heritability for all measured parameters. These results showed that screening program for obtaining high antioxidant activity and lower oxidant content could be performed in this population. Phenotypic correlation between hydrogen peroxide content with proline and with carotenoid content were positive but these correlation were genotypicaly negative indicating that genetically and naturally, proline and carotenoid content are working for detoxification of hydrogen peroxide but environment affects this relationship. So that, screening genotypes for higher content of proline and carotenoid content must performed precisely to gain higher detoxification of ROSs. INTRODUCTION Growing population in developing countries accompanied with high food consumption lead to high global demand on food. On the other hand, massive using of bred lines or synthetic cultivars results in germplasm uniformity and consequently crop vulnerability against biotic and abiotic stresses(STAT 2010). Expanding genetic diversity guarantees feeding world population and crop germplasm against adverse effects of environmental stresses. Variations in crop germplasms also increase the chance of finding high yielding plants for cultivation. Screening various germplasms is the first step of a basic program for selection of candidate genotypes for cultivation under targeted regions. One of the rich genetic resources are landrace varieties harboring valuable genes against adverse effects of biotic and abiotic stresses (Zeven 1998). A landrace is a local variety of a domesticated plant species which has developed largely by natural processes, by adaptation to the natural and cultural environment. Landrace differs from a formal breed which has been selectively bred deliberately to conform to a particular trait. Landraces are usually more genetically and physically diverse than formal breeds. The features of landrace varieties could be incorporated into commercial cultivars and inbred lines by under field hybridizations or in vitro transformation methods (Zeven 1998). Evaluation of the interrelationship of traits in crop germplasm is important for clarifying population structure and modelling selection criteria for increasing plant productions. Simple statistical analyses are not able to clarify cause and effect relations of important traits contributed to yield and other important trait's variation. Alternatively, the knowledge of genetic diversity is a useful tool in gene-bank management and plant breeding programs (Dwevedi and Lal 2009). Information of genetic parameters is also important in modelling selection approaches for improving crop structures (Khan and Qasim 2004). Estimating heritability of traits and the extent of genetic variation can be used in prediction of genetic advances in a crop population (Ali et al. 2008). Genotypic and environmental factors are necessary in breeding programs. Biological Forum – An International Journal 7(2): 43-47(2015)