引言六十年代后期世界上很多地方已经营建了桉树种子园,提供短轮伐期林分和主要是浆柏材用的种子,同很多针叶树相反,只有少数桉树种子园为提供锯材所用的材料。虽然桉树可能占据着世界人工林的五分之一(Logan,1967),但世界性的树木育种工作只对这个属从事了极小部分的努力。这是一个很难理解的问题,因为同针叶树来比,它生产的种子丰富和人工林的轮伐期短,育种投资的经济收益迅速和高得多。主要和原因 INTRODUCTION Eucalyptus seed orchards have been established in many parts of the world in the late 1960s to provide short-rotation stands and seeds mainly for pulpwood, in contrast to many conifers, only a few eucalyptus seed orchards are used to provide sawn timber . Although eucalyptus may account for one-fifth of the world’s plantation (Logan, 1967), worldwide tree breeding is a very small part of the effort. This is a difficult question to understand because the abundance of seeds it produces and the rotation of plantations are shorter than for conifers and the economic benefits of breeding investments are swift and much higher. Main and reason