In order to study apolegamy of Chinese-fir parent in cross breeding,genetic variability of photo-synthetic rate of parent clones and respiration rate of Chinese fir families has been researched,so that providing suitable female and male parents for cross breeding and establishment on biclonal seed orchard of Chinese fir. 40 parental clones in Suichang Chinese fir seed orchard were as study materials,genetic variability and parents selection have been studied for photosynthetic rate and respiration rate of Chinese fir.The main results were as follows:(1)At leaf-expansion period of fast growth,there is a significant correlation between total chlorophyll content and photosynthetic rate of Cunninghamia lanceolata.Photosynthetic rate can be predicted by total chlo-rophyll content at this time.(2)photosynthetic characteristics of parental clones of Chinese fir have a moderate genetic variability(GCV=17.56%)and the high degree of repeatability(R=92.71%).There were 12 parental clones(long8,long15,1244,1269,1366,1419,1278,Li8,Li4,Li55,1218 and 1276),having higher photosyn-thetic rate,being suitable for female parents for hybridization.(3)Same as photosynthetic characteristics,Chi-nese fir parental families have a high genetic variability(GCV=41.67%)in respiration rate and the high de-gree of broad-sense heritability(Hf2=96.42%).There were 8 parents families(1339,Li55,Jing70,1278, Yun17,Long4,Cang2 and 1218)having higher respiration rate,being suitable for male parents for hybridiza-tion.(4)In Cunninghamia lanceolata,a few parents having the higher rate of photosynthesis usually have the lower respiration rate,and vice versa.So from the perspective of genetic breeding issues,to get a better proge-ny,the way of cross breeding was used only for aggregating fine characteristics of photosynthesis and respira-tion,developing better strains of Chinese fir,vegetative use and biclonal seed orchard were used for utilization of Chinese fir breeding achievements.%为研究杉木育种园亲本无性系的净光合速率和亲本家系的呼吸速率的大小和遗传变异,以便给杉木杂交育种亲本选配和双系育种园的建立提供优良的母本和父本.以遂昌杉木育种园中(即1.5代种子园)40个亲本无性系为研究材料,展开净光合速率和呼吸速率的大小和遗传变异性研究.结果发现:(1)展叶速生期,杉木的总叶绿素含量与净光合速率间存在极显著相关,因此可用此时的总叶绿素含量来预测其净光合速率;(2)杉木亲本无性系间的光合特性具有中度的遗传变异性(GCV=17.56%)和强度重复力(R=92.71%);有龙8、1244、1269、1366、1419、1278、龙15、丽55、丽8、丽4、1218和1276等12个亲本净光合速率较高,适合做杂交的母本.(3)与光合特性一样,杉木亲本家系的呼吸速率具有中度以上的遗传变异性(GCV=41.67%)和强度广义遗传力(96.42%);有1339,丽55,靖70,1278,云17,龙4,苍2和1218,共有8个亲本家系,其亲本适合于做杂交的父本.有丽55、1278和12183个亲本无性系既可作杂交的母本,又可作杂交的父本.(4)在杉木中,亲本间的净光合速率与呼吸速率存在负的弱的秩相关(rs=-0.2021),并仍存在如下现象:少数优亲,其净光合速率高,但其呼吸速率往往较低,反之亦然.因此从遗传育种学的角度看问题,要获得优良的种子,只有采用杂交育种的方式,来聚合杉木优良的光合和呼吸特性,并采用双系育种园的方式或无性利用的方式来利用杉木杂交育种的成果.
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