| Mytilaria laosensis is an important broad-leaved tree species indigenous to the tropical and subtropical areas of south China due to its rapid growth,straight trunk and good wood quality.In order to evaluate comprehensive performences of half-sib progeny tested forest of M.laosensis at the age of six,and to accelerate the selection process of superior provenances/families,the genetic variations of phenotype,growth and wood properties were revealed,fast-growing type,good quality of wood type and both were excellent type of M.laosensis provenances/families were determined and analyzed based on M.laosensis provenances/families experimental forest.The main conclusions were as follows:(1)There were significant differences in phenotypic traits among and within 8 provenances of M.laosensis.Variation was greater within provenance(18.08%)than among provenance(5.68%).Mean phenotypic differentiation coefficient was 35.10% among provenance.Among different provenances,mean CV value of all traits of GXDB provenance was the biggest(18.41%),and that of GXLZ provenance was the smallest(16.10%).8 provenances of M.laosensis can be divided into three kinds of source distribution area.It was suggested that the main source of the phenotypic variation in M.laosensis was from pedigrees within provenances and the main variation was caused by the change in latitude.(2)There were highly significant differences among growth characters at family and provenance level.At the age of 6,height(H),diameter at breast height(D)and volume(V)of the best provenance GXPX was 1.28,1.42,2.30 times of worst provenance GXFC respectively.Mean individual volume of best family PX01 with 0.1016 m3 was 4.01 times of worst family FC01 and 1.94 times of the average of total families by comparison.2 superior provenances were selected from 8 tested provenances,and genetic gain of H,D and V of those superior provenances was 8.87%,11.79% and 34.70% respectively.12 superior families were selected from 123 tested families,and genetic gain of H,D and V of those superior families was 11.57%,17.35% and 52.06% respectively.(3)There were significant differences in fiber length(FL),the ratio of fiber length to fiber width(FL/FW)and tiny fiber compositions(TF)at provenance level,but there were no significant differences in fiber width(FW)and Wood base density(BD)at family level.Average of FL was 1.40 mm,and that of BD was 0.46882g/cm3.The provenance heritability of M.laosensis wood properties ranged from 15.08% to 78.07%.The family heritability of M.laosensis wood properties ranged from 7.08% to 47.56%.Two superior provenances were selected from 8 tested provenances,and genetic gain of FL,FW,TF and BD of those superior provenances was 0.43%,0.34%,0.20% and 0.21% respectively.Six superior families were selected from 123 tested families,and genetic gain of FL,FW,TF and BD of those superior provenances was 1.59%,1.31%,2.88% and 2.42% respectively.(4)The relationship between H,D and V,and that between FL and FL/FW,FW and growth traits were significantly and positively correlated,but other traits were not significantly correlated.It was suggested that in addition to FW,growth traits were independent to fiber characteristics,so growth and fiber characteristics should be chosen independently in order to obtain ideal selection effects.There was no significant correlation between growth traits and ecological factors,but the BD was significant and positively correlated to the altitude,and that was negatively correlated to average annual temperature.(5)There were significant differences in growth traits and wood characteristics at provenance level,and there were significant differences in H,D,V,BD and BD at family level.The provenance heritability of each trait ranged from 15.08% to78.07%,and the family heritability of that varied from 7.08% to 63.51%.Two superior provenances were selected from 8 tested provenances,and genetic gain of H,D,V,BD,FL and TF of those superior provenances was 4.98,6.53%,19.98%,0.05%,-0.36%and 1.23% respectively.Twelve superior families were selected from 123 tested families,and genetic gain of H,D,V,BD,FL and TF of those superior provenances was 7.66%,9.46%,26.11%,1.52%,0.81%and 0.87% respectively. |
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