新一轮毛白杨遗传改良策略的思考和实践

Thinking and practices for strategy on a new round genetic improvement of Populus tomentosa

该文针对国内外社会和经济环境变化对杨树需求的影响,在分析毛白杨遗传改良的研究现状和存在的问题基础上,结合近年来毛白杨良种选育工作思考和实践结果,提出新一轮毛白杨遗传改良策略。即针对不同的栽培区和不同的生产应用需求制定育种目标,重点选育速生、优质、高抗的用材林和绿化雄株品种,以及抗寒抗旱、耐高温水湿品种。针对毛白杨分布区气候区划以及自然群体遗传分化特点,在不断充实位于分布区南部的冠县基因库的同时,增设北部基因资源保存库,实现毛白杨基因资源分区域有效保存和利用。针对毛白杨良种选育中一直未能充分利用母本效应的问题,通过基因库半同胞子代群体分析筛选育性好、一般配合力高的毛白杨母本,采用分子标记鉴定半同胞群体优良单株的父本,并通过主要目标性状指标和遗传多样性综合评价,构建适宜不同育种目标的育种亲本群体,进而通过配子染色体加倍技术选育毛白杨杂交和三倍体新品种。针对当前白杨主要通过嫁接繁殖技术环节复杂、成本高以及苗木易老化等问题,采取利用组织培养苗和根蘖苗幼化的特点,通过容器硬枝扦插和大田硬枝扦插,实现毛白杨良种低成本、高效率快速规模繁殖的技术路线等。

In this paper,in view of the significant effects of social and economic changes on poplar demands,a new round of genetic improvement strategy for Populus tomentosa was proposed based on analyzing the current situation and problems in combination with thinking and practices on variety breeding. It is necessary to design appropriate breeding objectives for different cultivation areas and application requirements,especially to select male varieties with fast-growth,high-quality and high resistance for timber forest and landscape,as well as the varieties exhibiting strong resistances to cold,drought,high temperature and water. According to the climatic regionalization and genetic differentiation of the natural populations,it should not only enrich the existing gene pool in the south distribution area（ Guanxian County,Shandong Province）,but also establish a new one in the north distribution area. Thus effective sub-regional preservation and utilization of P. tomentosa genetic resources would be realized. To solve the problem that it is still not taking full advantage of maternal effect in P. tomentosa breeding,screening out female parents with good fertility and high general combining ability though the analysis of half-sib progenies in the gene pool,and identifying the male parents for the superior individuals using molecular markers should be conducted. Furthermore,building a parents group that is suitable to different breeding objectives though the comprehensive assessment on main traits and genetic diversity to produce newvarieties of P. tomentosa allotriploid using the gametes chromosome doubling technique is feasible. Given the complex grafting technology,high-cost,and easy aging of the seedlings for P. tomentosa breeding,exploiting the rejuvenation of tissue culture plantlets and suckers,vessel and field hard-wood cutting will be a good way to fulfill low-cost,effective and quickly large-scale propagation for P. tomentosa.