Growth performance and stability analysis of poplar clones based on BLUP and GGE biplot under two different geographic sites in China

In this study, we tested the growth performance of Populus deltoides clones at two different geographic sites in China. Diameter at breast height (DBH) for 37 clones was measured through four consecutive years, and data were subjected to analysis using a linear mixed-effects model with heterogeneous errors. Subsequently, the best linear unbiased prediction (BLUP) values were analyzed with genotype main effect plus genotype-environmental interaction effect (GGE) biplot to evaluate tree growth performance and site effects. Results demonstrated that two principal components of the GGE biplot accounted for 99.70 % of the total variance, confirming the reliability of the results. GGE biplot analysis revealed no correlation between the two sites, with Yancheng (site 1) demonstrating better discriminative power and both sites showing similar representativeness. Single-site BLUP analysis indicated that clone 761, 1049, 1228, and 875 had the largest DBH at site 1, while clone 436, 107, and 230 performed the best at site 2 (Xiangyang). Cross-site BLUP analysis revealed that clone 761, 875, and 1517 had the best overall DBH growth, and clone 761 exhibited the fastest growth rate at site 1. While clone 436 performed the best at site 2, followed by clone 107, 230, 1220, and 1514. For stability test, clone 1517, 2072, and 587 were the best clones across sites. Overall, clone 875 and 1517 excelled both with growth rate and stability across the tested sites, making them suitable for widespread promotion. The BLUP-based GGE biplot provided an effective evaluation tool for testing the hybrids and filed trial sites, offering support for selection and application of poplars in China. • BLUP and GGE biplot analysis was used to assess genotype stability and adaptability, improving genotype selection accuracy. • Clone 761 exhibited the highest diameter at breast height at site 1, while clone 436 performed best at site 2. • Cross-site BLUP analysis identified clone 875 and 1517 as recommended candidates for large-scale commercial plantations. • GGE biplot analysis revealed no correlation between the two test sites, with site 1 demonstrated stronger discriminative ability.