Open Access

ARTICLE

Association Mapping of Hundred-Grain Weight in Paeonia ostii Using SSR Markers of Transcription Factors from the Comparative Transcriptome

Xin Guo^1,2, Shuangting Qi², Lian Duan², Xueyuan Lou², Xian Wang², Songlin He^1,*, Fangyun Cheng^3,*

1 College of Landscape Architecture and Art, Henan Agricultural University, Zhengzhou, China
2 College of Horticulture, Henan Agricultural University, Zhengzhou, China
3 National Engineering Research Center for Floriculture, College of Landscape Architecture, Beijing Forestry University, Beijing, China

* Corresponding Authors: Songlin He. Email: ; Fangyun Cheng. Email:

(This article belongs to the Special Issue: Ornamental Plants: Traits, Flowering, Aroma, Molecular Mechanisms, Postharvest Handling, and Application)

Phyton-International Journal of Experimental Botany 2026, 95(4), 16 https://doi.org/10.32604/phyton.2026.076905

Received 28 November 2025; Accepted 25 March 2026; Issue published 28 April 2026

Abstract

Plant quantitative trait allelic variation stems from complex regulatory networks. Tree peony, which is native to China, is a unique woody plant with ornamental, medicinal, and oil-producing value. Paeonia ostii, as an important species of tree peony, has emerged as a novel woody oil crop in recent years. However, research on functional genes associated with yield traits in P. ostii remains relatively limited. To gain deeper insights into the genetic architecture underlying one of the three key yield components—grain weight—in this study, a genome-wide association map for 123 unrelated P. ostii was constructed by integrating short-read and long-read sequencing. From 959 screened yield-related candidate transcription factors, 57 polymorphic expressed sequence tag-simple sequence repeats (EST-SSRs) were identified. In combination with 24 previously reported polymorphic EST-SSRs linked to tree peony seed yield, 81 markers were utilized for genotyping 123 P. ostii materials. These EST-SSRs showed high genetic diversity and low linkage disequilibrium. Additionally, population structure analysis revealed two distinct subgroups within the mapping population. Furthermore, 21 EST-SSRs were significantly associated with hundred-grain weight according to mixed linear model (MLM) association analysis. These loci primarily originated from the AP2, TCP, YAB, WRKY, WD, BHLH, and MADS-box gene families, contributing to phenotypic variation at rates ranging from 9.15% to 35.94%. Through sequence alignment analysis, we determined that WRI1, ERF7, NGAL3, and YAB1 might serve as key candidate genes regulating seed weight in P. ostii, highlighting their significant research value and warranting further investigation. The findings of this study provide valuable resources for elucidating allelic variation in the quantitative traits of oil-producing woody perennials.

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