Study On Inheritance And Variation Of Wood Property In Populus Tomentosa Carr.

Populous tomentosa Can., a native species in China, has played a key role in timber production and ecological environment construction along the Yellow River. It is mainly distributed in the vast area of northern China, and occupied about one million km~2. Study on inheritance and variation of wood property for excellent clones, collected from 8 provinces or city in China, found the base of scientific theory for improvement of important traits of wood property, and has great practical significance in Populus tomentosa.A total of 574 clones sampled from 8 provenances, i.e. Beijing, Hebei, Shandong, Henan Shanxi, Shannxi, Anhui, and Jiangsu, planted in the national gene pool of Populous tomentosa, were studyed on inheritance and variation of wood property with wood basic density, fiber length, fiber width, ratio of fiber length to width and ratio of wall to cavity. The patterns of inheritance and variation among provenances, clones and sample locations in radial direction were analyzed. The major results and conclusions are described as follows.1. Variation of wood property among provenances is of significant difference at the level (P >0.01) in Populous tomentosa. The variation range among provenances at different sample locations of fiber length, fiber width were 0.4204g/cm~3～0.4615g/cm~3,0.75mm～1.56mm and 18.46um～28.86um, respectively. As for the wood basic density, an important trait, its repeatability of among provenances was 0.926. On average, repeatability among provenances at different sample locations of fiber length, fiber width, ratio of fiber length to width and ratio of wall to cavity respectively were 0.976, 0.971, 0.942, 0.809. The results showed that the traits of wood property among provenances were mainly controlled by genetic factors. From the multiple contrast among provenances of wood property, the patterns of variation between each two provenances were strongly different in different traits and samples locations in radial direction.2. The variation of wood property in provenances was apparent in Populous tomentosa. The maximum values of wood basic density, fiber length and fiber width appeared in Beijing provenance, they respectively were 0.4814g/cm~3 , 1.97mm, 38.85um. The minimum value of wood basic density , 0.4204 g/cm~3, appeared in Anhui provenance, the other two traits, e.l., fiber length and fiber width appeared in Hebei proveance, they respectively were 0.44mm and 8.43um. Variation of the wood property in provenance were significant difference (P>0.01), except for the wood basic density. The average repeatability of fiber length, fiber width, ratio of fiber length to width and ratio of wall to cavity were 0.946, 0.949, 0.935, 0.905, respectively. The results showed above revealed that the traits of wood property in provenances were mainly controlled by genetic factors in Populous tomentosa.3. The variation of wood property in radial direction marked the patterns of changes, i.e., The patterns of variation of fiber length and ratio of fiber length to width with radial direction was similar. They are continually come up to the maximum with direction of from marrow to cortices, and then fixed. Pattern of changes of fiber width and ratio of wall to cavity were waved above and below along one center point. Variation of the wood property in different sample locations were different at the level of P>0.01. The average repeatability at different sample of fiber length, fiber width, ratio of fiber length to width and ratio of wall to cavity were 0.992, 0.888, 0.983 and 0.920, respectively.The results showed above indicated that the variation of all important traits of wood property analyzed in this study were significant difference in provenance, among provenances, and in different sample locations in radial direction, and they were mainly controlled by the genetic factors. This study provided important theoretical foundation for selection of excellent clones, parental selection of hybridization and molecular breeding for improvement of wood property. The results, therefore, will produce the important effects on genetic improvement of industrial feedstocks of fiber material in P. tomentosa.