Masoumeh Nemati - University of Mohaghegh Ardabili, Ardabil, Iran
Ali Asghari - University of Mohaghegh Ardabili, Ardabil, Iran
Omid Sofalian - University of Mohaghegh Ardabili, Ardabil, Iran
Ali Rasoulzadeh - University of Mohaghegh Ardabili, Ardabil, Iran
Hamidreza Mohamaddoust Chamanabad - Mohaghegh Ardabili, Ardabil, Iran

Abstract To study the effect of water stress in rapeseed cultivars at the seedling stage, ۱۰ rapeseed cultivars were evaluated at three irrigation levels [normal irrigation (control) and irrigation after depletion of ۶۰ and ۸۵% of available soil water]. Analysis of variance showed considerable variation among cultivars. Water stress reduced all of the studied morphological characteristics, especially shoot and root dry weight, root volume and increased chlorophyll content and chlorophyll fluorescence. Cluster analysis at three levels of irrigation regime, assigned cultivars in different groups. Cultivars Licord, Opera and SLM۰۴۳ were grouped together and showed higher average for all traits compared with other cultivars at all of the irrigation conditions. ISSR analysis using ۱۱ primers produced ۵۴ polymorphic bandsin the studied cultivars. Mean PIC and MI of all primers were ۰.۲۱ and ۱.۰۳, respectively. Cluster analysis based on molecular data using Nei's genetic distance assigned the cultivars into three clusters. Associations between molecular markers and morpho-physiological traits, were assessed by stepwise multiple regression analysis at different stress levels. The highest amount of variation contributed by ISSR markers belonged to relative leaf water content (۷۸%) at non-stress condition, to root/shoot index (۶۶%) at moderate stress condition and to root length (۵۳%) at severe stress condition.

Genetic variation, ISSR markers, Rapeseed, Water Stress