越南黄花梨种源家系生长遗传变异及早期选择

【目的】对越南黄花梨幼林阶段生长表现进行研究,为筛选早期生长性状优良的越南黄花梨家系,以及越南黄花梨引种选择提供依据。【方法】对4年生的越南黄花梨10种源46个家系的早期生长性状进行调查,在分析生长性状遗传变异的基础上进行早期优良种源和家系的选择。【结果】越南黄花梨早期生长性状在种源、家系间达到显著以上差异,表型和遗传变异系数分别为10.81%~36.97%和4.20%~10.95%。各性状的种源重复力、家系遗传力和单株遗传力分别为(0.45±0.19)~(0.81±0.06),(0.27±0.16)~(0.59±0.09) 和(0.18±0.13)~(0.35±0.19)。运用综合指数选择,综合生长指标、叶型和冠幅性状选出早期优良种源2个,优良家系6个。优良家系的树高、胸径、地径、叶色值、叶片叶绿素SPAD值以及冠幅的平均遗传增益为6.87%、6.54%、6.77%、2.62%、3.50%和9.43%。【结论】8号(兴安)种源不仅生长优良,而且存在着丰富的遗传变异,可作为越南黄花梨引种栽培的首选种源。

Genetic variation and juvenile selection of growth traits of Dalbergia tonkinensis Prain

【Objective】Dalbergia tonkinensis Prain,commonly known as Mai Dou Lai in Vietnam is a semi deciduous tree belonging to the genus Dalbergia,family Papilionoideae.The genetic variability and genetic-phenotypic correlations among growth traits were studied for screening the excellent genetic materials of D.tonkinensis at an juvenile stage.It helped the germplasm introduction of D.tonkinensis and the development of precious timber industry in Guangdong Province.【Method】The growth traits include tree height,diameter at breast height,diameter at ground height,crown,leaf chlorophyll SAPD value and leaf area were studied in the 4 years old,provenance/family testing trail in Baishengyuan,Yangjiang City,in west Guangdong Province.The genetic parameters were estimated for each trait using mixed linear model.Further,we selected the excellent provenances and families using exponential equation.【Result】The average annual growth in height and ground diameter of D.tonkinensis was 1 m and 3 cm,respectively.The coefficient of variation of diameter(26.86%-40.41%)was higher than that of tree height(25.27%-26.35%).There were different phenotypic and genetic variations in the growth characters for D.tonkinensis.The phenotypic variation coefficient ranged from 10.81%(leaf chlorophyll SPAD value)to 36.97%(ground diameter 17).The genetic variation coefficient ranged from 4.20%(leaf chlorophyll SPAD value)to 10.95%(ground diameter 17).The coefficient of variation of tree height was consistent among all the characteristics at juvenile stage.The provenance repeatability,family and individual heritability were recorded as(0.45±0.19)to(0.81±0.06),(0.27±0.16)to(0.59±0.09)and(0.18±0.13)to(0.35±0.19),respectively.Highly significant positive genetic correlation was observed between growth characters(P<0.01).Significant(P<0.05)or extremely significant genetic positive correlation(P<0.01)was observed between growth traits and leaf chlorophyll SPAD value and crown,except leaf area traits.Genetic correlation among leaf chlorophyll SPAD value,leaf area and crown were not observed.Based on phenotypic and genetic variation of growth traits,the early index selection of excellent provenances/families was carried out with tree height,DBH,ground diameter,leaf chlorophyll SPAD value,leaf area and crown diameter(measured in 2018).The provenance index coefficients of tree height,DBH,ground diameter,leaf chlorophyll SPAD,leaf area and crown diameter were 0.78,0.54,0.48,0.11,0.05 and 0.87,respectively.The average aggregation index of provenance was 17.62±1.88.Two excellent provenances(No.3 and No.8)were selected as their aggregation index of multiple traits was greater than the average value+1 standard deviation(mean+SD=19.50).The average genetic gain of tree height,DBH and DBH for excellent provenances was 43.06%,101.46% and 115.84%,respectively.Six excellent families were selected according to the index of family aggregation(11.81)constructed based on population mean values.The selection rate was 13.03%.The genetic gains of tree height,DBH,ground diameter,leaf chlorophyll SPAD value,leaf area and crown diameter of the selected population were 6.87%,6.54%,6.77%,2.62%,3.50% and 9.43%,respectively.【Conclusion】There are abundant provenance and family variations among the early growth characters for D.tonkinensis.The genetic control of growth and wood properties at provenance and families were observed above moderate intensity.The highly genetic variation of the introduced germplasm of D.tonkinensis provided a basis for genetic breeding,and this can be further used for genetic improvement of D.tonkinensis.