基于环境和年龄效应的湿地松材性遗传改良研究

Pinus elliottii (slash pine) is one of the most important coniferous timber species in southern China. As ratio of the field of materials for building, furniture and papermaking is increasing year over year and demand of wood is becoming more and more, genetic improvement of wood properties has been an important development trend of genetic improvement of Pinus elliottii. However, constraining by the small sample size and limitation of the detection technology, the genetic variation of wood properties at site and family/site levels has not yet been revealed. Besides, wood properties' response to the environment and age changes and its mechanisms has not yet been determined either. This will cause an adverse impact on process of genetic improvement for wood property..In this project, large sample data for wood properties of slash pine will be obtained from family trial with one rotation age based on NIRS prediction models for wood property parameters. The family trials are from different areas in Jiangxi province. The data will experience efficient statistical analysis, and on this basis, our results will reveal the space effects and genetic variation with site and family/site levels of wood properties, determine the influence of genotype, environment and interactions between genotype and environment on wood properties and their underlining mechanisms. The results would also confirm the genetic stability of different families in different environments and their proper planting area..Regarding radical variation of parameters of wood properties as the cutting point, the effects of age on wood property formation and the prediction model will be investigated and established, respectively. Meanwhile, the optimum age of early selection of slash pine for woods production will be selected, which will provide theoretical basis for the advanced generation genetic improvement of slash pine for timber production and high quality cultivation of slash pine forest plantation.

湿地松作为我国南方重要的用材树种，其在建筑、家具、造纸等用材领域的比重正逐年上升，木材需求量越来越大，材性遗传改良已成为湿地松遗传改良的重要发展方向。然而，由于受到样本量的限制及检测手段的制约，目前尚未明确湿地松材性在不同层次的遗传变异规律及其对环境和年龄变化的响应机制，影响其材性遗传改良进程。本项目拟利用已达1个轮伐期的湿地松区域化多点家系试验林，在建立NIRS材性预测模型的基础上，获得多点全林材性大样本数据并进行高效分析，系统研究以阐明材性空间效应及遗传变异规律，明确基因、环境以及基因与环境的互作效应对材性形成的作用机制，确定不同家系在不同环境的遗传稳定性及其适栽范围。以不同材性性质参数的径向变异规律为切入点，探讨年龄效应对湿地松家系材性形成的影响并建立预测模型，确定不同材性性状早期选择最佳年龄，为湿地松材性遗传改良及人工林优质培育提供重要科学理论依据。

湿地松作为我国南方重要的用材树种，材性遗传改良已成为湿地松遗传改良的重要发展方向。基因和环境交互效应是优化材性性状遗传评估体系的重要机制和科学前沿；材性性状随生长发育的遗传响应机制尚未明确。本项目以已达1个轮伐期的湿地松区域化多点家系试验林为研究对象，在建立近红外（NIRS）材性性状预测模型的基础上，获得多点全林材性性状大样本数据并进行高效分析，系统研究以阐明材性性状在不同层次遗传变异模式及其对环境变化的响应机制，揭示不同生长发育阶段遗传效应对材性形成的作用规律，明确不同材性性状早期选择最佳年龄。结果表明，不同材性性状随生长发育的径向变异模式不一，根据有序聚类最优分割法，幼龄材与成熟材的分界点为树木生长的第21年，基于不同材性预测方程，应用幼龄材来预测成熟材，实现湿地松材质的早期预测是可行的；湿地松不同材性性状遗传力、早-晚遗传相关系数以及早期选择效率随生长发育呈动态变化，根据不同材性性状遗传参数随年龄的动态变化规律，确定湿地松木材品质性状早期选择的最佳年龄在7~8年生，纤维解剖性状的早期选择最佳年龄为6~10年生。湿地松材性性状NIRS模型构建结果表明，不同材性性状校正模型和验证模型的各项校正和验证参数均处于较优水平，模型的预测能力较高，可以用于未知样品的检测。“微环境”条件下材性空间分析中，有5个性状表现出明显的空间异质性，考虑空间效应能够改善模型的拟合效果，对于无明显空间效应的性状，采用基础模型进行遗传分析即可。“宏环境”条件下，综合不同材性性状地点效应分析和B型遗传相关分析结果来看，湿地松家系材性的遗传稳定性较高，受环境影响较小；采用Smith-Hazel指数选择法对不同区域湿地松家系进行材质性状的综合评价，根据指数方程所选家系组合在生长和纸浆材材性上相对家系总体均值均有一定程度的改良和提高。本研究结果为湿地松材性性状遗传改良及人工林优质培育提供重要科学理论依据。