中文摘要：

通过对白桦杂交子代种苗性状的分析，估算白桦亲本的遗传参数，为白桦第二代强化种子园的亲本选配提供理论依据．2003年在白桦强化种子园中以小北湖（BH）3个优树、帽儿山（M）2个优树作为杂交亲本，按5×5完全双列交配设计进行控制杂交，测定白桦25个杂交组合种子的千粒重、发芽率、发芽势及其苗高、地径等．结果表明，25个杂交组合的种子千粒重、发芽率、发芽势及其苗高、地径均存在着极显著的差异；千粒重、发芽率和发芽势的一般配合力、特殊配合力、反交效应差异也达到了极显著水平，苗高的一般配合力差异显著，而地径的一般配合力差异不显著，苗高和地径的特殊配合力及反交效应差异极显著；根据杂交子代一般配合力效应值和特殊配合力效应值，从25个杂交组合中初选M4×M1、BH3×BH2、M4×BH3、BH2×BHl、BH2×M1组合为优良组合，M4和BH3为优良亲本．

英文摘要：

Betula platyphylla is an important industrial wood species with fast growth, strong adaptability and good timber. The genetic parameters of its parents were estimated by analyzing F1 descendant for seed and seedling traits in order to select optimum parents for the second generation seed orchards of birch. Five parents of birch from Xiaobeihu （BH） of Ning＇ an County as well as Maoershan of Shangzhi County of Heilongjing Province were crossed by a 5 by 5 diallel cross design in 2003 and their hybrid seeds and seedlings were tested on thousand-grain-weight, germination percentage, germination viability, seedling height, and ground diameter. The results indicated that there were significant differences at of seed and growth traits among crossing combinations, and specific combining ability （SCA） and reciprocal effects percentage and germination viability of seed, SCA and REC the 0.05 level of probability are there statistically significant the probability of 0.01 level in the characteristics also in the general combining ability （GCA）, （ REC ） of thousand-grain-weight, germination of seedling height and ground diameter. Only at differences in the GCA of seedling height, and the differences in GCA of the ground diameter of seedlings were not significant. M4 ×M1, BH3×BH2, M4 ×BH3, BH2× BH1 and BH2×M1 are superior cross combinations given the effects of GCA and SCA. Also M4 and BH3 are superior parents.