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白榆(Ulmus Pumila Linne)是重要的造林树种,它广泛分布在苏联的中亚、西伯利亚,中国的北部及蒙古、朝鲜等国家。在我国栽培历史悠久,自然分布于北纬32°—51°41′,东经75°—132°之间的冀、鲁、豫等十八个省(市、自治区)。白榆生长快、材质好、适应性强、繁殖容易,是平原农区植树造林的优良树种。但过去对白榆未开展系统的树种改良研究,至今干形弯曲,主干低矮,出才率低未能充分挖掘和发挥该树种的遗传增产潜力。
Ulmus Pumila Linne is an important afforestation species widely distributed in the Central Asian countries of the Soviet Union, Siberia, northern China and Mongolia, North Korea and other countries. The cultivation in our country has a long history and naturally distributed in eighteen provinces (cities and autonomous regions) such as Hebei, Shandong and Henan between 32 ° -51 ° 41’N and longitudes 75 ° -132 ° E. White elm grow fast, good material, adaptability, easy reproduction, is an excellent tree species in the plain farming afforestation. However, in the past, the research on the systematic tree species improvement of Ulmus did not dry up, the trunk was low and the rate of emergence was low. Therefore, the genetic increase potential of this species was not fully tapped and exploited.