3年生不同倍性白桦家系生长性状变异分析及优良家系的选择

杂交子代生长性状的测定以及优良家系的选择是研究林木育种的重要环节。为了选择优良的白桦杂交子代，本研究以3年生21个不同倍性的白桦家系为材料，对其树高、胸径和材积进行变异分析，结果表明：各性状在不同家系间差异均达极显著水平（P<0.01）；且各性状家系遗传力均高于0.75，属于高度遗传；家系311-15在树高、胸径和材积方面均表现最优，其树高、胸径和材积分别高于其他家系均值的9.09%、11.25%和40.46%；家系311-9、311-25和211-7、211-2、211-3、211-6、211-1等表现较好，其树高、胸径和材积与家系311-15相比差异未达显著水平。运用隶属函数综合评定法，以20.00%的入选率对参试家系进行选择，311-15、311-9、211-7、211-2等4个家系入选，这4个家系的树高、胸径和材积的遗传增益分别为5.24%、7.18%和19.72%。在进行优良家系选择的同时，以材积平均值+2倍标准差为标准，共筛选出52株优良单株。研究结果为白桦优良家系及优良单株在辽宁省西南部的推广提供参考，也为高世代三倍体制种园的改建提供依据。

Growth Traits Variation Analysis and Family Selection of 3-year-old Various Ploidy Betula platyphylla

The growth traits analysis and family selection of tree progeny are important links in the tree breeding. To select excellent birch hybrid progeny, 21 Betula platyphylla families were employed to determine the height(H), diameter at breast height(DBH) and volume(V) of 3-year-old seedlings. Results of variance analysis showed that differences of all growth traits among different families were highly significant(P<0.01). Family heritability of H, DBH and V were all higher than 0.75, belonging to highly inheritance. The family 311-15 was excellent at H, DBH and V, and 9.09%, 11.25%, 40.46% higher than other families, respectively. Moreover, there were not significant differences between triploid families 311-9, 311-25, diploid families 211-7, 211-2, 211-3, 211-6, 211-1 and triploid family 311-15 at H, DBH and V. Based on the analysis of subordinate function, triploid families 311-15, 311-9 and diploid families 211-7, 211-2 were selected as excellent clones when the selection rate was 20.00%. The genetic gains of four clones on H, DBH and V were 5.24%, 7.18% and 19.72%, respectively. Taking the average volume+2S as standard, 52 superior individuals were screened out. These results provide a reference for the popularization of birch excellent family and superior individual selection at southwest of liaoning, also form an important basis for alterations of high generation triploid seed orchards.