棉花(GossypiumhirsutumL.)种子形态结构对种子萌发有显著影响,生长和质量形成。然而,棉花种子形态的广泛变化使得用传统的表型获取方法很难实现定量分析。近年来,显微CT技术的应用使种子的三维形态结构分析成为可能,在准确鉴定种子表型方面显示出技术优势。在这项研究中,基于Micro-CT技术重建种子形态结构,深度神经网络Unet-3D模型,和阈值分割方法,提取了11个基本表型性状,构建了3个新的种皮比表面积表型性状,种皮厚度比和种子密度比,利用102份具有明显年份特征的棉花种质资源。结果表明,棉籽大小与籽粒和种皮体积之间存在显着正相关(P<0.001)。相关系数在0.51~0.92之间,而腔体体积与其他表型指标的相关性较低(r<0.37,P<0.001)。中国自交系品种种子体积变化的比较表明,种子表面积,种皮体积,空洞体积和种皮厚度增加了11.39%,10.10%,18.67%,115.76%和7.95%,分别,而种子内核体积,籽粒表面积和种子丰满度下降7.01%,0.72%和16.25%。结合聚类分析的结果,在中国棉花百年栽培史上,结果表明,种子结构的比表面积降低了1.27%,种皮的相对厚度增加了8.70%,种子结构的致密性提高了50.17%。此外,基于Micro-CT技术开发的新指标能够充分考虑指标中的三维形态结构和截面特征,体现技术优势。在这项研究中,构建了棉花种子微观表型研究体系,揭示了我国棉花种子形态随年份的变化规律,为种子形态的定量分析和评价提供了理论依据。
Cotton (Gossypium hirsutum L.) seed morphological structure has a significant impact on the germination, growth and quality formation. However, the wide variation of cotton seed morphology makes it difficult to achieve quantitative analysis using traditional phenotype acquisition methods. In recent years, the application of micro-CT technology has made it possible to analyze the three-dimensional morphological structure of seeds, and has shown technical advantages in accurate identification of seed phenotypes. In this study, we reconstructed the seed morphological structure based on micro-CT technology, deep neural network Unet-3D model, and threshold segmentation methods, extracted 11 basics phenotypes traits, and constructed three new phenotype traits of seed coat specific surface area, seed coat thickness ratio and seed density ratio, using 102 cotton germplasm resources with clear year characteristics. Our results show that there is a significant positive correlation (P< 0.001) between the cotton seed size and that of the seed kernel and seed coat volume, with correlation coefficients ranging from 0.51 to 0.92, while the cavity volume has a lower correlation with other phenotype indicators (r<0.37, P< 0.001). Comparison of changes in Chinese self-bred varieties showed that seed volume, seed surface area, seed coat volume, cavity volume and seed coat thickness increased by 11.39%, 10.10%, 18.67%, 115.76% and 7.95%, respectively, while seed kernel volume, seed kernel surface area and seed fullness decreased by 7.01%, 0.72% and 16.25%. Combining with the results of cluster analysis, during the hundred-year cultivation history of cotton in China, it showed that the specific surface area of seed structure decreased by 1.27%, the relative thickness of seed coat increased by 8.70%, and the compactness of seed structure increased by 50.17%. Furthermore, the new indicators developed based on micro-CT technology can fully consider the three-dimensional morphological structure and cross-sectional characteristics among the indicators and reflect technical advantages. In this study, we constructed a microscopic phenotype research system for cotton seeds, revealing the morphological changes of cotton seeds with the year in China and providing a theoretical basis for the quantitative analysis and evaluation of seed morphology.