不同种源大白杜鹃种子表型性状和发芽特性分析及其综合评价OA

[Objective]The phenotypic traits and germination characteristics of Rhododendron decorum seeds from different provenances were explored to provide a scientific support for breeding of improved R.decorum varieties.[Method]The variation and hereditary characteristics in phenotypic traits(seed length,seed width,seed thickness,samara length,samara width,seed size index,length-width ratio,flatness rate and 1000-seed weight)and germination traits(germination potential,germination rate,germination index,vigor index,radicle length,plumule length)of R.decorum seeds from six provenances in Guizhou province(Leigongshan National Nature Reserve,Zhongshan district in Liupan-shui city,Baili Dujuan Management District,Weining county,Hezhang county and Majiang County)were analyzed by correlation analysis,cluster analysis,principal component analysis,and comprehensive evaluation methods.[Result]There were significant differences(P＜0.05)in seed phenotypic traits among different provenances except for length to width ratio.The variable coefficient and heritability of seed pheno-typic traits were 9.64％-43.56％and 0.522-0.978,respectively.The seed length,seed width,samara length,and samara width of R.de-corum seeds from Leigongshan and Majiang provenances were higher.The maximum seed thickness,seed size index,flatness rate and 1000-seed weight of R.decorum seeds from Weining and Hezhang provenances,Hezhang provenance,Baili Dujuan provenance,and Majiang prove-nance,respectively.There were no significant differences in seed germination traits among 6 provenances except for seed germination rate and plumule length.The variable coefficient and heritability of seed germination traits were 8.75％-30.01％and 0.34-0.84,respectively.The lowest seed germination rate(32.3％)and highest plumule length(2.15 mm)of R.decorum seeds were from Baili Dujuan provenance and Leigongshan provenance,separately.The seed germination rate and germination index were positively related to seed thickness and seed size index significantly or very significantly,and negatively related to seed flatness rate significantly or very significantly.The latitude was negative-ly related to seed germination rate and germination index significantly.The altitude was positively and significantly related to vigor index.The frost-free period was negatively related to vigor index and radicle length significantly or very significantly.The longitude,annual mean temper-ature,annual mean precipitation and frost-free period all were positively correlated with seed length,seed width,samara length and width sig-nificantly or very significantly.Six R.decorum provenances were clustered into three groups of Group Ⅰ(Leigongshan and Majiang),Group Ⅱ(Zhongshan,Weining,and Hezhang)and Group Ⅲ(Baili Dujuan).The comprehensive score of six R.decorum provenances was Leigongs-han＞Majiang＞Hezhang＞Weining＞Zhongshan＞Baili Dujuan.[Conclusion]There are significant differences in phenotypic traits of R.de-corum seeds among six provenances,and the phenotypic traits of R.decorum seeds have the higher heritable variation and heritability.The R.decorum seeds from Leigongshan provenance can be used as a potential source for genetic breeding and seed propagation.The R.decorum seeds from Baili Dujuan provenance should be conserved in situ and ex situ to prevent population decline and genetic resources loss.