Trait Variations and Probability Grading Index System on Leaf-Related Traits of Eucommia ulmoides Oliver Germplasm

Abstract

Eucommia ulmoides Oliver (EUO), an economic tree grown specifically in China, is widely used in various fields. To satisfy the requirements of industrial development, superior varieties need to be selected for different uses. However, there is no unified standard for breeders to reference. In this study, leaf-related traits were classified by a probability grading method. The results indicated there were significant differences between different planting models for the studied traits, and the traits in the Arbor forest model showed more abundant variation. Compared with genotype, the planting model accounted for relatively bigger variance, indicating that the standard should be divided according to planting models. Furthermore, the optimum planting model for different traits would be obtained by analyzing the variation range. Association analyses were conducted among traits to select the crucial evaluation indexes. The indexes were divided into three grades in different planting models. The evaluation system on leaf-related traits of EUO germplasm was established preliminarily, which considered planting models and stability across years for the first time. It can be treated as a reference to identify and evaluate EUO germplasm resources. Additionally, the study served as an example for the classification of quantitative traits in other economically important perennial plants.

Phenotypic Trait Subdivision Provides New Sight Into the Directional Improvement of Eucommia ulmoides Oliver

“…Comparative transcriptome analysis has been performed to identify candidate genes related to chlorogenic acid biosynthesis (Ye et al, 2019). Furthermore, researchers have established a probability grading index system to evaluate the economic traits of E. ulmoides germplasm (Deng et al, 2021). However, the study of phenotypic trait variations has been rare, a factor that has limited trait improvement (Wu et al, 2013;Pont et al, 2020) of E. ulmoides.…”

“…In 2005, its leaves and bark were listed in the "Pharmacopeia of China" (China Pharmacopeia Committee, 2005). In addition, it is used broadly in landscaping and gardens for its stronger adaption and rapid growth rate (Zhang, 1990;Deng et al, 2021). Hence, it is of high economic, ecological, and social value.…”

“…To satisfy their requirements, great improvements must be made in relevant traits. Gutta-percha, chlorogenic acid, and rutin are the main harvest products of E. ulmoides (Deng et al, 2021); hence, their contents (economic traits) and leaf yield determine the economic output. Growth traits, such as tree height, diameter at breast height, and ground diameter, can be used to measure the bark yield (Zhang et al, 2002) and growth situation (Li et al, 2014a;Jin et al, 2020).…”