一、初步的设想杂交是选育新类型的重要手段之一,在整个农业育种史中,通过杂交所获得的成果,占有显著的比重。林木育种的历史较短,但它一开始就应用了农业育种的经验,除了在现有的类型中进行选育之外,并开展了不同种系杂交工作。早在1912年,英国就用卡洛林杨(P.angulata)和毛果杨(P.trichocarpa)交配,选育了广泛栽培的品种 First, the initial idea Hybridization is one of the important means of breeding a new type, in the entire history of agricultural breeding, the results obtained by hybridization, accounting for a significant proportion. The history of tree breeding is relatively short, but from the very beginning it applied the experience of agricultural breeding. In addition to breeding in the existing types, cross breeding of different species was carried out. As early as 1912, the United Kingdom used P.angulata and P.trichocarpa to breed a wide range of cultivars