Читать книгу Biotechnology of Fruit and Nut Crops - Группа авторов - Страница 116

In order to overcome time-consuming breeding cycles in certain plant species, doubled haploid plants have been produced (Kasha and Maluszynski, 2003). Thanh-Tuyen and De Guzman (1983) and Monfort (1985) described early attempts for haploid recovery; however, ploidy level determination and plantlet regeneration were difficult. More recently, haploid embryos were induced from anther cultures, and plants were regenerated (Perera et al., 2007a, 2008a). The procedure involves a culture medium developed by Karunaratne and Periyapperuma (1989), containing 9% (w/v) sucrose (Perera et al., 2008a, 2009b) and activated charcoal (0.1%). Medium containing 100 μM 2,4-D, 9 μM TDZ and 100 μM NAA has been used for the induction and maintenance of haploid embryogenic cultures in darkness. Maturation of haploid embryos occurred on medium with 5 μM BA and 10 μM AgNO₃ (Perera et al., 2007b). BA (5 μM) and 0.35 μM gibberellic acid (GA₃) improved the germination of the haploid embryos (Perera et al., 2008a, 2009b). Flow cytometric analysis and histology have confirmed the haploid nature of the cultures, and the homozygous nature of regenerated plants (Perera et al., 2008b) was confirmed using a diagnostic SSR marker technique. Anther culture still requires further improvement to overcome the challenge of conversion, which is quite low, and improving recovery of diploid from haploid plants.