Tissue Culture And Chromosome Observation Of Rubus Fruticosus L.’Thornfree’

European blackberry (Rubus fruticosus L.), belonging to genus Rubus L.，familyRosaceae, is a kind of perennial deciduous shrub fruit trees with high economical andecological benefits. In China, there are lots of germplasm resources of Rubus. However, inmost areas they are wild, and systematically study and uses of these resources have not yetbeen carried out. While in some European and American countries, such as USA, Russia,Poland, a large amount of excellent blackberry varieties have been selected and cultivated inlarge area. So, it’s so urgently to introduce excellent varieties from abroad to accelerate theresearch and development of blackberries in China. European blackberry ‘Thornfree’(Rubusfruticosus‘Thornfree’) was introduced by our research group in2003from Poland. Being anexcellent thorn-free blackberry variety, it produces big fruits, stems are erect and generallybeing shelf cultivated. It is a leading cultivar in Poland and has great economical value. Rapidpropagation system and chromosome observation are conducted aiming to accelerate theextension of ‘Thornfree’. The main results are as follows:1. By systematically comparison of explants, basic medium, proliferation medium andgrowth regulator combinations, rooting medium and growth regulator combinations, theoptimum technique system on rapid propagation of ‘Thornfree’ was put forward as follows:media for a initialing, proliferating, and rooting culture were MS+6-BA1.0mg/L, MS+6-BA0.5mg/L+IBA0.1mg/L and MS＋IBA0.5-1.0mg/L, respectively. In propagationunder this system, the highest propagation coefficient was6.5and the rooting rate was100%.The rooted plantlets were transplanted to the glasshouse and then to field, and the survivedplantlets ratio to transplants was100%, which provided a theoretical basis to industrialpropagation and application for the European blackberry variety ‘Thornfree’.2. By comparing the effects of pretreatment time, time of wall degradation by enzymatichydrolysis, post hypotonic time on chromosome observation, the wall degradation hypotonicconditions for blackberry were optimized by showing pretreatment time of2h, enzymatichydrolysis of2h, post hypotonic time of30min, sampling from10:00-15:00and using roottip as materials.3. Based on blackberry chromosome observation system established above,‘Thornfree’ was determined as tetraploid with chromosome number of2n=4x=28.