白花泡桐种内多层次变异及其选择效果分析

对白花泡桐５０个种源５８０个家系进行了多水平试验研究，结果表明，白花泡桐的生长性状、感病指数、冻害指数和地理分布关系密切，长江中下游的种源生长最好、东北部的种源冻害最轻，并且生长和冻害性状呈连续的地理变异趋势；丛枝病的感病指数与种源地理分布之间的关系不显著.生长、抗病能力和适应性状在种源间存在极显著的差异，一些种源内家系间的生长及冻害差异也十分明显.各性状的变异为种源间大于种源内家系间，并且家系内个体间也存在着丰富的变异.最后作者对白花泡桐进行了种源、家系、个体不同层次的选择.经选择所得的优良家系的树高、胸径、材积、感病指数和冻害指数的遗传增益分别达到１７．０６％，１９．１６％，４３．１１％，６１．６６％及１０８．２３％.

Multi -level Interspecific Variation and the Analysis of Selection Effect on Paulownia Fortunei

Through the multi-level experiments on 50 provenances,580 families,it isshown that there are extremely significant differences in growth.Resistance to disease andadaptation among different provenances.The differences are also significant in growth a-mong families of special provenances.The variations of characters between provenances aregreater than those between families within a provenance.Meanwhile,there also exist plentiful variations between individuats within a familv.This indicats that it is necessarv for P.fortunei to be selected at 3 levels:provenance-family-iridividuat.The growth and freezingdamage index among provenances have obvious correlation with geographical distributionand they show a trend of successive variation.But the susceptible index of witcV;broomis not significantly related to the geographical distribution,and its variation is random.The provenancet;genetic abilities of growth and disease-resistance characteristics for P.fortunei aregreater than those of the families.By selecting superior families in elite p rovenaces,the geneticgain of tree height,D.B.H,volume and susseptible index are 17.06%,19.16%,43.11% and61.66%respectively.