旱柳野生种质资源收集及多样性分析

Collection and genetic diversity analysis of wild germplasm in Salix matsudana

【目的】在山东境内调查收集旱柳优树种质,探索旱柳种内遗传多样性水平。【方法】在试验区建立旱柳无性系苗期对比试验林,利用2年生苗木,分别进行表型数据观测和分子水平遗传多样性标记,分析旱柳种内遗传多样性。【结果】旱柳种质资源群体内存在丰富的表型变异和分子遗传变异:不同无性系枝干颜色呈黄绿、灰绿、绿色、灰褐、红褐、褐色,且色差重叠少,差异显著;主干有直立、稍弯、中等弯曲、较强弯曲、扭曲,小枝有上弯、直立、下垂,且形态差异显著;不同无性系树高变异范围为1.2~5.5 m,地径为0.6~4.6 cm,叶长为8.5~18 cm,叶宽为0.92~3.49 cm,叶面积为6.258~33.584 cm^2,差异极显著(P<0.001)。叶长和叶面积的极端差异来源主要是旱柳无性系内,树高、地径、叶宽的极端差异则主要来源于无性系间。表型变异主要来源于无性系间,无性系间的性状分化对旱柳种内性状分化的贡献率达80%以上,说明无性系间的性状分化是旱柳种内性状分化的主要原因。AFLP结果显示,旱柳观测位点的平均多态性比率高达99.5%,显示出极高的多态性;多样性指数结果显示,Nei’s遗传多样度(H)为0.232 2,Shannon信息指数(I)为0.374 6,表明55份种质在种水平上属于同一个种,与主成分分析及聚类结果一致。【结论】试验证明旱柳种内存在丰富的表型及分子遗传多样性,是优良的选择和杂交育种材料。

[Objective] The study was to explore genetic diversity within the species on the basis of surveying and collecting Salix matsudana germplasm in Shandong Province of eastern China. [Method]Contrasted experiment at nursery stage was built and seedlings of 2-year-old were used as materials for phenotype observation and molecular marker of genetic diversity. [Result] Results showed that color of stem and branchlet was discovered as kelly-green,grayish-green,green,grayish-brown,reddish-brown and brown; stem form showed from up-right to strongly curve; branchlet form was from upswept to straight to droop. Height ranged from 1. 2 to 5. 5 m with ground diameter from 0. 6 to 4. 6 cm after the same growth cycle. Similar situations also existed in length,width and area of leaves. Leaf length ranged from8. 5 to 18 cm,leaf width ranged from 0. 92 to 3. 49 cm and leaf area ranged from 6. 258 to 33. 584 cm2.Extreme discrepancy of leaf length and area were mainly from within clones,while those of height,ground diameter and leaf width were mainly from among clones. Main source of variation was from among clones,and trait differentiation among clones was the reason of segregation of traits of S. matsudana,with a contribution rate at more than 80%,meaning that differentiation among clones was the key for differentiation in the spices of S. matsudana. Results of AFLP showed a real high percentage of polymorphism on observed locus and average value could be 99. 5%. Diversity index revealed that Nei＇s index was 0. 232 2 and Shannon index was 0. 374 6,which meant all individuals could be the same species and principal component analysis and cluster analysis supported this conclusion. [Conclusion]Experiments showed that there exited abundant diversity in both phenotype and genotype traits,which proved Salix matsudana was great material on selection and cross breeding.