Selection and optimum fertilization of Betula platyphylla hybrid clones for growth

The different genotype response to fertilization varies greatly for tree growth. Therefore, the selection of superior genotypes and the optimal fertilization formula are important measures for cultivation of high-yielding forest. In this study, 30 hybrid clones of Betula platyphylla with supply different doses of formulated fertilization were used. Height, DBH (or ground diameter), and volume were recorded in 2-, 4-, and 5-year-old trees. Results showed that there were significant effects for clone, fertilization and age (P < 0.001), and significant interaction effects were found in clone x fertilization, age x genotype, fertilization x age, and genotype x fertilization x age (P < 0.05 or P < 0.01). The genetic correlation among growth characters showed that the height and ground diameter of 2-year-old seedlings had significant genetic correlation with year four and year five, thus the growth in 2-year-old clones can be used for selection criteria. Five superior clones were selected using membership function method. The genetic gains of height, DBH and volume were increased by 5.84%, 10.60% and 28.27%, respectively. The optimal fertilization was identified for each clone of B. Platyphylla and its hybrid with B. pendula.

Automated summary

The study highlighted the significant impact of fertilization on tree growth, emphasizing the importance of selecting the right genotypes and fertilization formula for successful forest cultivation. The growth characteristics of 2-year-old seedlings can serve as criteria for selecting superior clones. Through the membership function method, five superior clones were successfully identified, resulting in increased genetic gains in growth traits.