Studies On Geographic Variation Of Provenances Of Melia Azedarach And Preliminary Seclection

Melia azedarach from Melia,Meliaceae,is a kind of fast growing species with comprehensive utilization,which is always used in industry and furniture manufacture,meanwhile,it also is raw materials for botanical pesticides source and landscaping.For its well wood quality and fast growth speed,Melia azedarach has broad prospect,this research analyzed the geographic genetic variation of Melia azedarach with the purpose of improving the growth traits.During the Year of 2013-2014,three text forests of provenances in Guangdong Province were established.The growth data collected annually were analyzed with variance analysis,correlation analysis,regression analysis,stability analysis and cluster analysis.In this paper,growth variance between provenances was studied,and then,the trend of geographic variation and their climatic-ecological basis was explored.Lastly,some superior provenances were selected with outstanding growth performance,strong adaptability and well stability.The main conclusions obtained were as followed.(1)The growth situation of 3 sites were different,site Sihui had fast growth rate and nice sterm-form,while site Leizhou was better than site Zencgheng in growth performance,but worse in stem-form qualities and preserving rate.The coefficiency of variation of stem-form traits was bigger than growth traits,but the difference between provenances was smaller.Site Zengcheng had more obvious difference between provenances,while Site Sihui was the opposite.(2)The growth performance was different between sites and provenances,which was influenced by the environment of sites and the genetic factors of provenances.Growth traits had bigger variance between provenances,and stem-form traits were contrary to that.Survive rate had bigger variance in provenances compared with sites,which meant survive rate was impacted by the genetic factors of different provenances in great degree.(3)Each traits of Melia azedarach had obvious trend of geographic variance,and was affected by latitude,longitude and elevation,while latitude played the main role.Stem-form also influenced by longitude.Height and DBH had south-north gradient variation with changing of seed collected sites.Melia azedarach had progressively slower growth rate and worse stem profiles from southwest to northeast.(4)The geographic variation of Melia azedarach had obvious climate ecology basis.Provenances will grow faster in the areas associated with higher mean minimum temperature,milder extreme temperature,more precipitation amount and higher humidity.Besides,Provenances from where with lower air pressure and less sunshine will have better stem-form qualities and straight stem,while from areas with smaller wind speed will have stronger adaptability and high survive rate after introduction.(5)The provenances’ s comprehensive index in the front rank mostly from island or coastal areas including Hainan provenance,Guangdong provenance,Guangxi provenance,Fujian provenance,and mountainous areas including Guizhou provenance and Yunnan provenance.Furthermore,the provenances had inferior performance from northern or eastern areas.In site Zengcheng,superior provenance were selected out,including NO.629,NO.103,NO.843,NO.413,NO.856 and NO.349,while in site Leizhou,NO.413 was selected.Moreover,NO.843,NO.634,NO.413 and NO.849 were select as plus provenances in site Sihui.Cluster analysis showed that provenances had obvious group with differences.(6)The preserving rate of the provenances were ranked in top 30% in 3 sites,including NO.205,NO.204,NO.525,NO.103,NO.628,NO.846,NO.415,NO.845,NO.844,NO.413,which were suitable to plant widely in Guangdong provenance.(7)The 33 provenances in the text can be divided into four groups according to the stability between sites,including high-yield stable type,high-yield unstable type,slow-yield stable type and slow-yield unstable type.The first group including NO.206,NO.205,NO.413,were suitable for planting in the same or adjacent phenology,while high-yield unstable type had higher requirement for environment,so it needs to be promoted in some areas with suitable condition.