Key Laboratory of State Forestry and Grassland Administration on Tropical Forestry, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China.
Xinhui Research Institute of Forestry Science, Jiangmen, China.
PeerJ. 2024 Oct 15;12:e18218. doi: 10.7717/peerj.18218. eCollection 2024.
S.T. Blake, an important economic tree species, is widely cultivated as a raw material source for pulpwood, veneer plywood, and sawlog timber in southern China. As a tree in multiple environments, tree-breeding programs can assess genotype by environment (G × E) interactions and identify the suitable genotype for a specific environment. G × E interactions related to growth traits and soil factors have not been adequately studied for clones of and its hybrids. To examine this important question, trials containing 20 clones of and its hybrids were established at three sites in southern China: Shankou (SK), Tiantang (TT), and Xiniujiao (XNJ). These sites each have different soil conditions but similar geographical and climatic conditions. With the data across nearly eight years, average phenotypic trends and broad sense repeatability (H) were modeled, G×E interactions between clones and diverse soil environments were estimated, genetic gains of clones were calculated, and the adaptabilities of clones in different soil environments were compared. Average survival trends for clones tended to show a moderate decrease while growth traits tended to show sharp increases with age. At the same age, sites were ordered for average survival and growth traits as TT>SK>XNJ while H values for growth traits by site followed the basic order TT>SK>XNJ. The H values for growth traits at SK tended to increase at first, platform, and then smooth with age. The H values for growth traits at TT were high and stable across ages, and those at XNJ tended to undulate largely at a relatively low level across ages. Genetic correlations for growth traits between any pair of sites tended to increase at first and then decrease. A genetic correlation was strong between SK and TT, intermediate between SK and XNJ, and weak between TT and XNJ. It was concluded that: (1) clones tended to be adapted better to an environment with acidic and loamy soil with a clay content of about 45.6%, the soil depth from the surface to parent material about 1.5 m, and the previous vegetation of . (2) The G×E interactions between clones and sites are weaker if the environmental conditions between the sites are similar, and which are stronger if the environmental conditions between the sites are different. (3) The optimum selection age for clones ranged from 1.5 to 3.5 years old, while the optimum selection growth trait is individual tree volume.
S.T. Blake 是一种重要的经济树种，在中国南方被广泛种植，作为纸浆材、单板胶合板和锯材原木的原料。作为一种多环境树种，树木育种计划可以评估基因型与环境（G×E）的相互作用，并确定特定环境下的适宜基因型。对于 和其杂种的无性系，与生长性状和土壤因子相关的 G×E 相互作用尚未得到充分研究。为了研究这个重要问题，在 中国南方的三个地点（山口、天堂和新滘）建立了包含 20 个无性系和杂种的试验。这些地点的土壤条件各不相同，但地理位置和气候条件相似。通过近八年的数据，对平均表型趋势和广义重复率（H）进行了建模，估计了无性系与不同土壤环境之间的 G×E 相互作用，计算了无性系的遗传增益，并比较了 无性系在不同土壤环境中的适应性。无性系的平均存活率趋势呈中度下降，而生长性状则随着年龄的增长呈急剧上升趋势。在同一年龄，无性系的存活率和生长性状的顺序为 TT>SK>XNJ，而生长性状的 H 值则遵循基本顺序 TT>SK>XNJ。SK 地点的生长性状 H 值随着年龄的增长呈先增加、后平稳、再平滑的趋势。TT 地点的生长性状 H 值在各年龄段均较高且稳定，XNJ 地点的生长性状 H 值则在各年龄段呈较大波动且基本处于较低水平。任何两个地点之间的生长性状的遗传相关性呈先增加后减少的趋势。SK 和 TT 之间的遗传相关性较强，SK 和 XNJ 之间的遗传相关性中等，TT 和 XNJ 之间的遗传相关性较弱。研究结果表明：（1）无性系更适应酸性、壤土质地、粘土含量约 45.6%、从地表到母质的土壤深度约 1.5 米、前植被为 的土壤环境。（2）如果地点之间的环境条件相似，则无性系与地点之间的 G×E 相互作用较弱；如果地点之间的环境条件不同，则 G×E 相互作用较强。（3）无性系的最佳选择年龄范围为 1.5 至 3.5 岁，最佳选择生长性状为单株材积。
