磷高效马尾松种源磷效率的家系变异及苗期-大田回溯相关分析

从高磷效率的马尾松广东信宜种源中选择9个优良自由授粉家系,设置低磷和高磷两种养分环境,通过分析不同养分环境下植物生长量、干物质积累量和分配及磷效率（包括磷素吸收效率和利用效率）等指标,并结合5年生子代测定林生长状况的分析,研究马尾松广东家系对低磷胁迫的适应能力。结果表明:与一代种子园优良自由授粉家系相比,广东产地马尾松各家系总体上具有较好的适应低磷胁迫的能力,同时也存在着显著的家系变异。在参试的9个马尾松家系中,185,337,33和67家系表现较好,在苗高、地径和干物质量积累,以及根系参数和主要磷效率指标等方面都明显优于其他家系。在低磷胁迫环境下,337、185、67、336和33等高磷效率家系的根系主要参数也明显高于其他家系,表明整体根系参数的适应性变化是磷效率和生物量形成的决定因素。相关分析发现,这些性状之间具有显著或极显著的相关性,相关系数达到了0.700～0.999之间。通过苗期大田生长回溯相关分析发现,最重要的苗期磷效率指标干物质积累量,与大田条件下的树高性状均呈显著（p0.05）相关,而与材积性状仅达到0.10水平的相关（p0.1）。这一结果表明,通过马尾松家系的苗期磷效率指标,能预测大田生长条件下马尾松的部分生长性状,但尚不能较好地预测全部生长性状。本实验结果揭示,可以通过开展磷效率苗期盆栽试验来鉴定和筛选高磷效率马尾松家系,缩短林木遗传改良的选育周期,提高育种效率。

Family variation of Pinus massoniana in phosphorus efficiency and retrospective analysis between seedling growth and field trails

Pot experiment comprising treatments of high level and low level of phosphorus were conducted using 9 open-pollinated families randomly selected from Guangdong province.The purpose of this study was to disclose the adaptive mechanism of open-pollinated families of Pinus massoniana in response to low phosphorus stress,and to investigate the genetic variation in dry matter accumulation and phosphorus efficiency(PE) among open-pollinated families that originted from the province with high PE.The results show that most of the tested families exhibits relatively high PE and better growth performance in comparision with open-pollinated families that are randomly selected from the first-generation seed orchard.Moreover,significant genetic varitions in growth traits and PE are detected among the nine tested families,indicating the potential for selecting families with better growth performance and higher PE from provenance with high PE.Significant differences in plant height,ground diameter and dry matter accumulation among tested families are detected under the low P condition.Families of 185,337,33 and 67 exhibit better growth performances and higher PEs than those of other families under the low P condition.Further analysis reveals that significant genetic variations in root growth parameters including root length,root surface area and root volume.Families with higher PE have greater root parameters than those of the families with lower PE,and significant correlations with correlation coefficients of 0.700-0.999 are found between PE and root parameters.These results indicate that the genetic variations in root parameters should responsible for the family variations in PE and biomass accumulation.The results of the retrospective analysis indicate that there are positive correlations between growth traits in 1-year pot experiment and growth traits in 5-year-age progeny trials,and the correlation is significant at P<0.05 for plant height and significant at P<0.1 for wood volume.Based on the above results,the pot experiment can be used as an effective approach for early selection for genotypes with high phosphorus efficiency and favorite growth performance.