AWERProcedia Information Technology & Computer Science 1 (2012) 758-762 2 nd World Conference on Information Technology (WCIT-2011) Evaluation of partial resistance to basal stem rot in sunflower Robab Davar a *, Reza Darvishzadeh b , Sodabeh Jahanbakhsh-Godehkahriz c a Department of Biology, Faculty of Science, Payame Noor University, PO BOX 19395-3697 Tehran , Iran b Department of Agronomy and Plant Breeding, Urmia University, Urmia, Iran c Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Mohaghegh Ardabili,PO Box 179, Ardabil, Iran Abstract Sunflower, Helianthus annuus L. is a major oilseed crop widely cultivated throughout the globe. Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower ( Helianthus annuus L.). The experiment was conducted using recombinant inbred lines (RILs) coming from the cross between "PAC2" and "RHA266". Parents and 116 recombinant inbred lines (RILs) were arranged in completely randomized design with six replications and inoculated with an aggressive isolate of S. sclerotiorum in controlled conditions. Normality of the disease severity data was assessed according to the Shapiro and Wilk test (SAS PROC UNIVARIATE). Analysis of variance (ANOVA) of the disease severity data were performed using the general linear model (GLM) procedure in the SAS software (SAS Institute Inc.). High genetic variability and transgressive segregation were observed among recombinant inbreed lines (RILs) for partial resistance to S. sclerotiorum. Frequency distribution of RILs population and their parents for studied trait showed continuous patte rns, confirming that the resistance is controlled by a polygenic system. The information presented here could assist sunflower breeders to choose resistance genotypes to S. sclerotiorum basal stem disease. Keywords: Basal stem rot; Helianthus annuus L.; Partial resistance; Sclerotinia sclerotiorum; SAS software. Selection and peer review under responsibility of Prof. Dr. Hafize Keser. ©2012 Academic World Education & Research Center. All rights reserved. 1. Introduction Sunflower, Helianthus annuus L. is a major oilseed crop widely cultivated throughout the globe. It is a diploid species with an estimated haploid genome size of about 3,000 Mb with 2n=2×=34 chromosomes [2]. White mold, caused by necrotrophic pathogen Sclerotinia sclerotiorum (Lib.) de Bary, is a common and widespread pathogen of sunflower. When the climatic conditions are favorable for fungus, yield losses can reach *ADDRESS FOR CORRESPONDENCE: Robab, Davar,Department of Biology, Faculty of Science, Payame Noor University, PO E-mail address : Dr. R. Davar (Davar. Robab @gmail.com)/ Tel.: + 98 441 2973399; fax: + 98 441 2779558 BOX 19395 - 3697 Tehran , Iran.