杨树茎高-直径多阶段生长的QTL定位分析

[Objective]The purpose of this study was to explore the developmental genetic program of the transition between different stages in the process of poplar growth.Combined with the interaction relationship between traits growth,QTL mapping was carried out on the composite traits of height and diameter to analyze genetic structure of multi-stage growth and transition,which is of great significance for the forest cultivation and improvement of forest production.[Method]In this study,dynamic growth data of stem height and diameter over the first 24 years of a full-sib family of Populus including 64 hybrids along with two parents were studied.We present a complex multi-stage growth model(CMG)by incorporating Lotka-Volterra(LV)differential equations to describe the juvenile interaction between the two traits and two logistic functions to describe the growth and development of adults.CMG model are compared with the monophasic and diphasic logistic models.Based on the binary normal distribution of height and diameter,the associated QTLs controlling the growth transition of stages were identified by system mapping.[Result]Compared with the traditional monophasic and diphasic logistic growth models,the CMG model fitted poplar height and diameter growth data with higher accuracy.64 testcross QTLs and 117 intercross QTLs were detected to play an important role in regulating multi-stage height-diameter growth and these significant QTLs were distributed on chromosomes 1,2,5,8,9,11,12,13,14,16,17,18 and 19.These QTLs control the onset and offset,the duration,the phase transition time,and the maximum phenotypic value and growth rate of stages.[Conclusion]Our CMG model provided useful tool for the analysis of multi-trait and multi-stage growth of trees,and the identified significant sites provided important reference for improving the quality of molecular marker breeding of forest trees.