Studies On The Regional Experiment And Propagation Technique For New Clones Of Taxodium 'Zhongshansha'

In order to provide the variety salt-tolerant and water-tolerant varieties in the littoral area ofjiangsu province, in this paper we specified the origin and the progress of cross-breeding of Taxodium 'Zhongshansha' in detail; and briefly introduced the morphologic features and growth characters of the new varieties of 'Zhongshansha'; put forward the purpose and meaning of the study. To promote the better clones of 'Zhongshansha', we carried out the regional, salt-tolerance and cutting experiment, then brought forward a series of the cultivation techniques which adapted to them. The experiment results were as follows:1.According to the growth status of the clones of 'Zhongshansha' in different areas, we speculated that the 'Zhongshansha' 118, 9, 102, 24 and 1 with the untesting clones 27 and 136 can be developed in wetland and plain ; 'Zhongshansha' 27, 136, 118, 24 and 'Zhongshansha' 1 can be popularized in littoral wetland.2. The influences of different varities,cutting media and NAA concentrations were compared on the rooting ability of the clones 'Zhongshansha'.The results showed that the rooting rate of the varities had obovious distinctions. The highest of the average rooting rate was 'Zhongshansha' 27, which was up to 76.2%; 'Zhongshansha' 118, 146, 24 were better than 'Zhongshansha' 302. The lowest rooting rate was 'Zhongshansha' 149, which was 9.01%; the effect of different NAA concentrations on the rooting rate had the obvious distinctions, when the NAA concentration was 1500ppm, the average rooting rate was the highest, which was up to 53.9%. The rooting rates of cutting were higher among 'Zhongshansha' 118, 27 and 146. The 'Zhongshansha'24 cut in the soil with the sand had higher rooting rate than the contrast varity 'Zhongshansha' 302 ,whose rooting rate was 45.5% ; whereas, the cutting rate were 12.1% in the soil with perlite and peat, 9.0% in the peat soil with ashes of husk of rice. The average rooting rate of 'Zhongshansha' 102 was higher than the contrast variety 'Zhongshansha' 302,25.1% in the soil with the perlite ,26.9% in the peat soil with the ashes of husk of rice and 12.6% in the soil with sand. The 'Zhongshansha' 1 and 149 were hard to reproduce after cutting, due to the rooting rate of'Zhongshansha' 1 and 149 were lower than 302 in three cutting media.3.We evaluated the salt-tolerant ability of the clones of 'Zhongshansha' by hydroponic culture and based on the relative growth rate(RG), the salt stress index(SI) and relative conductivity rate(RL). The results on the ability of salt-tolerant among different clones was distinctive.'Zhongshansha' 118 had better ability of salt-tolerance. 'Zhongshansha' 136, 1,146 and 149 had the middle ability of salt-tolerance, whereas, the ability was less among 'Zhongshansha' 102, 27 and 24. The indexes of RG ,SI and RL had the obivious relationship, they could also be the index evaluating the salt-tolerant ability of 'Zhongshansha'.4.Through comprehensive evalution, we pointed out the clones of 'Zhongshansha' which adapted to the different growth conditions in our province, the 'Zhongshansha' 118, 27, and 136, which were adaptable, grew quickly, and propagat easily, could be popularized in our province.