不同家系交趾黄檀种子萌发及幼苗生长差异

Variation of seed germination and seedling growth among different families of Dalbergia cochinchinensis

【目的】揭示交趾黄檀种子特性、变异规律及其对苗期生长的影响,筛选交趾黄檀优良家系。【方法】对来源于泰国的32个交趾黄檀家系的种子形态(种子长、种子宽、种子厚、千粒质量),发芽特征(发芽率、发芽势、发芽指数)和苗期生长性状(苗高、地径、生物量)进行综合评价分析。【结果】32个交趾黄檀家系种子表型性状变异丰富,不同种子形态性状在家系间均达到显著水平差异,千粒质量变幅为18.04～32.93 g (表型变异系数12.88%)。交趾黄檀发芽率、发芽势、发芽指数和苗期生长性状差异显著。千粒质量与苗高、地径呈显著正相关。综合相关性和隶属函数评价分析表明,20号、23号、18号家系综合表现较好。【结论】32个交趾黄檀家系在表型性状方面存在较大差异,20号家系在苗期生长表现最优,可作为交趾黄檀育苗的首选家系。

【Objective】Dalbergia cochinchinensis Pierre is a valuable,semi-deciduous rosewood of the family Papilionoideae,commonly known as Dahongsuanzhi.D.cochinchinensis has various beneficial characteristics,including its smooth texture,ability to be polished to a high gloss,great strength,corrosion resistance and good processing performance.To research the characteristics of its seed,performance of the seedling growth,and early seedling quality to a comprehensive degree,we used D.cochinchinensis seeds collected from 10 provenances in Thailand,Cambodia and China.Additionally,we analyzed the geographical variation of phenotypic traits and the quality classification/evaluation of the seedlings.From this,we preliminarily selected the superior provenance.Finally,we provided theoretical support for work regarding D.cochinchinensis and its suitable introduction,genetic improvement for introduction to the appropriate regions,and further genetic improvement and conservation of the germplasm resources in China.【Method】We analyzed the seed morphology(seed length,seed width,seed thickness and thousand-grain weight),germination characters(germination ratio,germination energy and germination index),and seedling growth traits(seedling height,seedling ground diameter and biomass)for 32 strains of D.cochinchinensis from Thailand.The ANOVA and Duncan’s multiple comparisons analysis of the seed morphology,seed germination characteristics,and seedling growth of each strain were carried out in the statistical software R version 3.4.2.Pearson’s correlation coefficient was calculated among the various traits.The membership function method was used to evaluate the different strains.【Result】There were significant differences in the phenotypic traits of the seeds among the strains.The variation in the seed length,width and thickness reached a very significant level in the 32 strains.The average seed morphology of the 32 strains was(6.63±0.56)cm in length,(4.41±0.41)cm in width,(1.19±0.14)cm in thickness,(25.15±3.2)g in thousand-grain weight,with phenotypic variation coefficients of 8.45%,9.29%,11.76%and 12.88%,respectively.There were also significant differences in the germination ratio,germination energy,germination index and seedling growth traits.The average seedling height,stem height and leaf area of the 32 strains were 33.88 cm,3.62 mm and 4.37 cm^2,respectively.At the seedling stage,the biomass of the leaves was the largest.The average total biomass,leaf biomass,root biomass and stem biomass were 2.55 g,1.05 g and 0.66 g,respectively.The variance analysis showed that there were significant differences in the biomass of different organs among the seedlings of different strains.The correlation between the thousand-grain weight and growth traits(seedling height and seedling ground diameter)were significant(P>0.05).According to the correlation analysis of different types of traits,the thousand-grain weight,germination rate,ground diameter,and total biomass were selected as the evaluation indexes.The strains were comprehensively analyzed.Strains No.20,No.23 and No.18 were better performers in the correlation and membership function analysis.【Conclusion】There were significant differences in the phenotypic traits among the germplasm.Strain No.20,which had the best seedling growth,could be used as a preferred strain.In the early growth stage,the seed germination rate and phenotypic characteristics will have some influence in the breeding selection,but the germination test and seedling characteristic evaluation are only the initial stages of seedling introduction and cultivation.The difference in seed quality is also related to the nutritional status and harvesting time of seed-bearing mother trees.The determination of the optimal strain is a comprehensive selection and evaluation problem.Solving this problem must be through subsequent seedling breeding,afforestation and progeny breeding.Further work needs to be focused on continuous tracking verification.The preferred strain selected in this study can provide some guidance for the further popularization,cultivation,improvement and domestication of this precious mahogany resource in China.This study provides a theoretical basis for the resource conservation and genetic improvement of D.cochinchinensis.