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 p0.05 for plant height and significant at p0.1 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.