白桦半同胞子代多点生长性状测定及优良家系选择

针对白桦种子园半同胞家系开展多点造林试验，不仅能够选择出性状优良的家系，而且也能加快种子园的改良进程。本文以白桦初级种子园中53个半同胞家系为对象，分别在朗乡、帽儿山、吉林等3个试验点营造试验林，对12年生试验林各家系的树高、胸径和单株材积等性状进行多地点联合分析。单株材积及树高生长量在地点间和家系间以及地点与家系的交互作用上均表现为差异极显著(P＜0.01)，胸径生长量在家系间和地点间也表现为差异极显著(P＜0.01)。根据多重比较的结果分别在各试验点进行了优良家系的初选，同时，采用BLUP模型对多地点参试家系材积育种值进行估算，依据育种值高低对参试家系进行综合评价，以20.00%入选率为标准，B34、B15、B28、B16、B51、B40、B42、B45、B48、B35、B19入选为优良家系，其材积均值分别较朗乡、帽儿山和吉林3个地点的家系均值高8.29%、9.80%和13.60%，材积性状在3个地点的遗传增益分别为3.23%、7.16%、8.84%。这11个家系的采种母树也入选为优良母树，其中B35和B15的采种母树为最优母树。研究结果不仅为白桦半同胞子代家系选择提供理论依据，而且也为白桦初级种子园的改良提供参考。 

Multipoint growth trait test of half-sibling offspring and excellent family selection of Betula platyphylla

Carrying out multipoint test for half-sibling families of seed orchard can not only select excellent families with superior growth traits but also accelerate the improvement progress. The height ( H ) , diameter at breast height ( DBH ) , volume ( V ) of 53 half-sibling families from birch primary seed orchard, which were planted in Langxiang, Maoershan, Jilin of northeastern China 12 years ago were used for multipoint conjoint analysis. The results showed that there were statistically significant ( P <0. 01) differences in H and V among different families and sites, and also significant in site × family interaction. The differences of DBH among different sites and families also reached statistically significant level (P<0. 01). According to multiple comparison result, excellent families were preliminary selected in various sites. Meanwhile, breeding value of tested families was estimated adopting best linear unbiased prediction model "BLUP" and the tested families were synthetically evaluated based on the level of breeding value. Using a selection rate of 20% as the standard, B34, B15, B28, B16, B51, B40, B42, B45, B48, B35 and B19 were selected as superior families, whose mean volume was 8. 29%,9. 80%and 13. 60% higher than the mean value of Langxiang, Maoershan of Jilin, and the genetic gains of volume trait in the three sites were 3. 23%,7. 16% and 8. 84%, respectively. The mother trees of these families were selected as excellent tree, in which the mother trees of B34 and B15 were the best. These results provide a theoretical basis for selection and a reference for the improvement of seed orchard.