Abstract. For accelerated development of fertility restorer lines with imidazolinone tolerance in sunflower (Helianthus annuus L.), the gamma-induced parthenogenesis, which combines classical breeding approaches and in vitro techniques, was applied. As initial materials six imidazolinone-tolerant hybrid combinations (F1203, F1216, F1246, F1248, F1295 and F1332)Keywords: sunflower, double haploid fertility restorer lines, embryo culture, gamma-induced parthenogenesis AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 9, No 3, pp -3, 2017 190 19 DOI: 10.15547/ast.2017
IntroductionThe herbicide-tolerant sunflower hybrids are generally preferred by agricultural producers in Bulgaria and this determines the main directions of contemporary sunflower breeding. Imidazolinone (IMI) and sulfonylurea (SU) tolerance to herbicides transferred to cultural sunflower from wild species is most often used (Kaya et al., 2012).The development of parental components for the hybrid is a necessary prerequisite for the production of sunflower hybrids tolerant to herbicides. The classical breeding approach for developing lines that can be included as parental components of hybrids comprises inbreeding of plants for at least 5 -6 years. To accelerate this process, a number of researchers have directed their attention towards non-traditional approaches for production of homozygotic lines. The development of plant biotechnologies opened new opportunities in this respect. One of the methods for accelerated development of haploid and double haploid lines is the gamma-induced parthenogenesis (Todorova et al., 1997;Gok Guler et al., 2015;Blasco et al., 2016;Wang et al., 2016). The use of this method significantly shortens the time necessary to develop parental lines for heterosis breeding in sunflower Ivanov, 1999, 2000). The properties of the double haploid lines obtained through this method are determined by the genetic potential of the initial material they were derived from. In spite of the unquestionable benefits from the use of biotechnology methods for acceleration of the breeding process, there are many cases in which they are influenced by the genotypic responsiveness of the investigated plant material (Sauton, 1989;Bouvier et al., 1993;Faris et al., 1999;Todorova et al., 2004;Taşkın et al., 2013;Drumeva and Yankov, 2015). Therefore, additional investigations and certain modifications of the standard methodologies are necessary depending on the specific requirements of the genotype.This study was aimed at investigating the genotypic responsiveness of sunflower hybrid combinations with expressed herbicide tolerance to the application of the gamma-induced parthenogenesis method for accelerated production of imidazolinones-tolerant fertility restorer lines.
Material and methodsAs initial materials for parthenogenetic induction six imidazolinone-tolerant hybrid combinations (F1203, F1216, F1246, F1248, F1295 and F1332), obtained from Dobrudzha Agricultural Institute, General Toshevo, were used. For initiation of parthenogenetic embryo devel...