Open Access

ARTICLE

Leaf Morphological Variation and Heterosis on Hybrid Progenies of Populus ussuriensis and P. simonii × P. nigra

Heng Zhang^1,#, Meng Wang^1,#, Dong Zeng^1,2, Yunbo Xu¹, Dongyuan Guo¹, Xuanchen Liu^1,3, Zhanqi Ren⁴, Jinzi Zhang¹, Yuhang Liu¹, Qiuyu Wang¹, Shuo Yu¹, Guanzheng Qu^1,*

1 State Key Laboratory of Tree Genetics and Breeding, School of Forestry, Northeast Forestry University, Harbin, 150040, China
2 Institute of Fruits and Vegetables, Xinjiang Academy of Agricultural Sciences, Urumqi, 830091, China
3 Heilongjiang Academy of Forestry, Harbin, 150040, China
4 College of Life Science, Northeast Forestry University, Harbin, 150040, China

* Corresponding Author: Guanzheng Qu. Email:
# These authors contributed equally to this work

Phyton-International Journal of Experimental Botany 2025, 94(10), 3205-3216. https://doi.org/10.32604/phyton.2025.069994

Received 05 July 2025; Accepted 24 September 2025; Issue published 29 October 2025

Abstract

Hybridization remains an important method for breeding new poplar varieties. It results in significant variation in leaf phenotype among parents and offspring, and among offspring themselves. This study aimed to investigate whether leaf shape variations were similar in offspring produced from reciprocal crosses. Specifically, two hybrid combinations were produced: the direct cross with Populus ussuriensis as the maternal parent and P. simonii × P. nigra as the paternal parent (HY53), and the reciprocal cross with P. simonii × P. nigra as the maternal parent and P. ussuriensis as the paternal parent (HY268). Using 3-month-old rooted cuttings from 40 clones (36 F₁ hybrids and their parents) growing in a greenhouse, we measured and analyzed 14 leaf morphological traits to assess genetic variation and heterosis. The results showed HY53 clones generally exhibited greater average height than HY268 clones. Leaf phenotypes differed between the two hybrid combinations, with significant differences observed among parents and offspring for almost all traits, as revealed by analysis of variance (ANOVA). The phenotypic coefficient of variation was higher in HY268 clones. Additionally, leaf traits demonstrated high repeatability. Notably, some hybrid offspring exhibited positive or negative mid-parent heterosis, as well as over-parent heterosis for certain leaf phenotypes. The systematic cluster analysis further indicated distinct separation among HY268 clones. This research provides valuable materials for poplar breeding and offers insights into hybrid vigor in wood plants. The findings highlight the importance of reciprocal crossing in influencing leaf phenotype variation and heterosis, offering practical insights for future breeding strategies.

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Supplementary Material

Supplementary Material File

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