M. Drumeva*, P. Yankov Department of Plant Production, Faculty of Shipbuilding, Technical University Varna, 1 Studentska, 9010 Varna, Bulgaria (Manuscript received 6 March 2017; accepted for publication 3 July 2017) Abstract. For accelerated development of fertility restorer lines wit

M. Drumeva*, P. Yankov Department of Plant Production, Faculty of Marine Sciences and Ecology, Technical University Varna, 1 Studentska, 9010 Varna, Bulgaria Abstract. When applying gamma-ionizing radiation for induction of parthenogenetic doubled haploidy, the female genotype exercis