| Melia azedarach Linn.from Melia,Meliaceae,which is widely distributed in China with fast-growing and multi-purpose.It is often used in the fields of architecture and furniture,garden greening,biological pest control and so on.It has high timber value and medicinal value,and has a broad development prospect.Based on the observation results of the provenances-families of Melia azedarach in Leizhou and Zengcheng,this study analyzed the trend of geographical genetic variation and evaluated the tested provenance-family.Preliminary screening some excellent provenances and families with outstanding growth performance,good adaptability and high stability.The main conclusions are as follows.（1）All characters of M.azedarach provenance showed abundant phenotypic variation at two sites,especially the variation range of tree height and DBH.The differences among provenances were significant,so provenance selection had great potential.The percentage of variance components between provenance and block interaction of most characters was higher than that of other factors,and the growth performance was greatly influenced by environment,so it was significant to carry out multi-site provenance test.There were differences in growth quantity among different provenances,and the difference of growth characters was more significant than that of morphological traits.（2）The height,DBH,crown width and survival rate of M.azedarach provenance were mainly controlled by latitude,while the height under branch and stem shape were mainly controlled by longitude,and there was no significant correlation between the 6 trites and altitude.At the same time,the geographical variation of Melia azedarach has obvious climatic and ecological basis.The provenances from the areas with moderate temperature,abundant precipitation,low air pressure and less sunshine grow faster,preserve better andhave better dry shape.（3）Among the characters of each test site,tree height and DBH were the main contributing traits,followed by stem shape and crown width.Fifty-three provenances were divided into4 categories.The first group included 15 provenances such as NO.101,NO.350,NO.628,NO.102 and NO.845,most of which were provenances in western fujian,southern guizhou,south-central jiangxi and southeast guangdong.Category 2 includes 24 provenances,including No.206,526,630,349,629 and so on,mainly from northern Guangxi,southern Hunan,northwest Guangdong,southern Yunnan,southwest Guizhou,and south-central Hainan Province.The third category includes 10 provenances,such as NO.248,1162,858,842 and 1464,were mainly from east-central Sichuan Province,northwest Guizhou Province and north-west region.The fourth category included NO.959（Linan,Zhejiang）,1869（Jingmen,Hubei）,NO.1666（Baoding,Hebei）and NO.1768（Tai’an,Shandong）.（4）There were significant differences in provenance repeatability and genetic variation coefficient among the characters of M.azedarach in different test sites.Tree height and DBH were controlled by strong genetic control,and branch height and stem shape were controlled by weak genetic control.（5）In Leizhou and Zengcheng,11 superior provenances with great comprehensive performance were selected,and further to the average height,average DBH,average genetic gain were greater than the top 20% average,average survival rate is higher than sites as standard screening excellent provenance.In the end,five provenances were selected from both sites,which were NO.631（Qinzhou,Guangxi）,NO.413（Yunan,Guangdong）,NO.415（Kaiping,Guangdong）and NO.843（Caiheng,Guizhou）.NO.349（Xingning,Hunan）,NO.856（Pingtang,Guizhou）.（6）In Leizhou,NO.846,412 and NO.631 had average genetic stability,the genetic stability of NO.415,413,204,630,857,102,417,629,842 was lower than that of average（bi>1）,and the genetic stability of No.205,856,103,526,845,525,739,418 was higher than that of average（bi<1）.Provenances of NO.844 were found to have an average stability at Zengcheng test,and the genetic stability of NO.856,413,651,629,855,349,103 and843 was lower than the average,the genetic stability of NO.631,526,525,741,206,204,416,415 were higher than average.（7）The phenotypic difference among the characters of Leizhou family was significant,so the family selection basis was good,the growth performance of each trait in different families was influenced by non-genetic factors,the interaction effect between the block and the family was very significant,and the proportion of variance component was larger.There were significant differences in the growth amount,especially in the preservation rate,followed by DBH.And the order of the same family in different characters was also quite different.In terms of tree height,DBH,stem shape and preservation rate,only 8 families performed well.（8）Most of the characters of family were significantly or extremely significantly correlated with each other,among which tree height and DBH were highly positively correlated,crown width was significantly negatively correlated with branch height and dry shape.The larger the tree body,the larger the volume and the more luxuriant the branches and leaves were,the more obvious and straight the trunk is.The genetic correlation of each trait showed a high positive correlation at the family level,and the genetic correlation coefficient of DBH was the largest.（9）There were significant differences in heritability and coefficient of genetic variation among the families.In general,the growth traits（tree height,DBH,crown width）were under strong genetic control,while shape and quality traits（branch height,dry shape）were under weak genetic control.（10）The breeding value of each trait of Melia azedarach family was different greatly,the average seed value of DBH was the largest,followed by crown width and tree height,and the mean seed value of subbranch height and stem shape was the lowes.Comprehensive various characters,with tree height,DBH and breeding values are in the top 10%,and the survival rate is not lower than the average level of standard screening,only 10 families were selected as excellent families,mainly from Renhua,Guangdong（31,35,36）,and Yunan,Guangdong（40,41,42）.Guangxi Rongan（102,106）.Hainan Tunchang（224）and Hainan Wuzhishan（239）.（11）According to the comprehensive index method preliminary screening 23 superior families with excellent performance,which are NO.41,NO.42,NO.35,NO.239,NO.75,NO.33,NO.72,NO.131,NO.40,NO.243,NO.77,NO.34,NO.36,NO.102,NO.52,NO.106,NO.66,NO.60,NO.121,NO.223,NO.347,NO.227,NO.224,mainly from Yunan,Renhua,Enping,Qingyuan,Kaiping,Rongan,Guangxi,Sanjiang,Hainan,Wuzhishan,Lingshui and other areas in Guangdong,mainly from Yunan,Renhua,Enping,Qingyuan,Kaiping,Guangxi’s Rongan,Sanjiang,Hainan’s Wuzhishan,Lingshui,and other regions,mainly from the Guangdong’s Yu Nan,Renhua,Enping,Qingyuan,Kaiping,Guangxi’s Rongan,Sanjiang,Hainan’s Wuzhishan,Lingshui.Based on the analysis of genetic gain,the average tree height,average DBH and average genetic gain of only 5excellent families were higher than those of the first 10% families,which were from Renhua（33,35）,Yunan（41,42）and Hainan（239）,respectively.The results were in good agreement with the results of breeding value.It was found that provenances from South China grew prominently and had stronger adaptability at the test site.（12）Among the 22 overlapping families ranked in the top 20% of the 4-year composite index,no.31,33,40,52,66,72,75,77,131 and 243 families had average genetic stability.The genetic stability of no.35,41,42,70,113 and 239 families was lower than average.The genetic stability of no.36,53,121,200,214 and 224 families was higher than average. |
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