| Masson pine(Pinus massoniana Lamb)is an important fast-growing,well-tolerated dominant tree for timber and resin usage with abundant genetic diversity,which was widely distributed in southern China.Currently,different types of masson pine germplasm were used to carried out the following work: 1)identification of germplasm to low-phosphorus stress tolerant by measuring their morphological and physiological biochemistry difference;2)elucidation of genetic polymorphism and relatedness using ISSR and IRAP molecular marker technologies,construction of a genetic linkage map;as well as detection of QTL associated with growth traits based on the phenotypic traits measured in the 6 successive years,which may facilitate the germplasm utility and genetic breeding of masson pine.The results were as follows:1)Using perlite-cultured method watered with nutrient solution,seven provenances from six provinces,including identified four low phosphorus resistance provenances was measured with five agronomic traits as well as 10 physiological and biochemical traits after stress treatment under three low phosphorus concentrations for 60 d,each provenance showed differences in traits.On basis of principal component analysis,membership function analysis on growth of measured plants,and relative value of physiological and biochemical indicators,a comprehensive screening indicator D was figured out,and a provenancefrom Meishan in Sichuan Province demonstrated the strongest tolerance to mild,moderate and severe low phosphorus stress.Through system clustering analysis based on all D values under different concentration with the longest distance method and subject to low phosphorus tolerance with Euclidean Distance equal to 0.44,showed that the seven Pinus massoniana provenances might be divided into three categories,in which provenance of Meishan in Sichuan Province singly was clustered into the first one;provenances from Longyan and Wuping in Fujian province,showing lower phosphorus tolerance belonged to the second category;the other four provenances were grouped into the third category,as the phosphorus nutrition sensitive types.Based on gray relational analysis on relevance between all physiological and biochemical indicators and low phosphorus stress,the indicator order reflecting low-phosphorus tolerance was carotenoids >MDA > root activity >total chlorophyll >Pro > SOD > CAT >POD>SP > SS,suggesting that Pinus massoniana tolerance to low phosphorus stress mainly was regulated through photosynthetic pigments,root activity as well as protecting enzyme system.2)A total of 192 families of masson pine were collected from seed orchards in Guizhou Province,Fujian Province and Guangxi Province,and their genetic diversity was evaluated by ISSR markers,.Totally,183 polymorphic bands were scored by 12 ISSR primers,with a polymorphic rate of 98.87%.Cluster and PCA analysis showed that germplasms from the same seed orchard always were closely related,particularly,that with the same specific traits might be grouped into the same category.Three fast growing families from Guangxi Nanning,namely 29-1,31-1 and 33-1 were classified as same category individually,and demonstrated far genetic relationship away from other germplasms.According to "good traits-location" method,192 families might be divided into six groups,and AMOVA analysis showed that 71.8% of genetic variation came from within group,while 28.2% were from different groups since the genetic differentiation was much bigger among each group and the genetic differentiation coefficient was 0.226.FG-DY demonstrated the highest degree of genetic variation,and might generated high heterosis crossed with germplasm from other seed orchards.3)Based on the RT sequence of retrotransposon LTR for two families,42 IPAP primers were designed in current study.Compared with ISSR marks,allele observed value Na of 60 masson pine families,genetic diversity H of Nei's and Shannon diversity index I were higher than former at the species level.In addition,IRAP marker could detect more homologous information between Guangxi and Fujian germplasms,including detection of high-yielding ester families at both places and effectively identify the red heart woods.Primer P-3,SAR1,PPT2,P-12 and P-16,could be used to distinguish the tested families separately.The five primers could be used as the core marks for masson pine germplasm identification.4)Seventy five half-sib progenies of “No.83 clone” were used as the mapping population and double pseudo-test strategy was employed for mapmaking.After chi-square test under the significance lever of P= 0.05,56 ISSR markers and 154 IRAP markers met Mendel separation ratio,accounting for 60.9% of the total polymorphic markers.We carried out chain analysis on the aforementioned markers by Ici Mapping Version4.1 Software and constructed a Genetic Linkage Frame Diagram consisting of 12 linkage groups(LOD=3).The map included 205 markers,with the total map distance of 4081.01 c M,and average distance between two adjacent markers were 19.91 c M and genomic coverage was 88.6%.Marker quantity in each linkage group was from 10(Chromosome 4)to 43(Chromosome 1);Length of each linkage group is from 70.04 c M(Chromosome 4)to 617.69 c M(Chromosome 1),with the average length of 340.08 c M.The minimum distance was located in the fourth linkage group with an average interval of 7 c M,and the maximum was located in the second linkage group with an average interval of 27.81 c M.Constructed genetic map could be used as QTL detection of growth-related-traits of Pinus massoniana.5)The interval mapping method was used to carry out QTLs position detection of tree height,breast diameter,material volume for 10-15 a year old trees and crown breadth form 10 a year old trees.When LOD value of confidence coefficient was 3,8,16,72 and 3 QTLs were detected to be related to tree height,breast diameter,single tree timber volume and crown breadth,respectively.Some QTLs detected were multi-effective,five QTLs were detected to locate in four different linkage groups,and more than two growth traits located in each accumulation area.Expression of QTLs was somewhat unstable in different years,however,a QTL of material volume was detected in the 1st and 7th linkage group(QV1-1,QV7-1);QTL QV2-1,which controls the annual expression of breast diameter,was detected in the 2nd linkage group. |
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