Exploring the Genetic Architecture of Root-Related Traits in Mediterranean Bread Wheat Landraces by Genome-Wide Association Analysis

Abstract

Background: Roots are essential for drought adaptation because of their involvement in water and nutrient uptake. As the study of the root system architecture (RSA) is costly and time-consuming, it is not generally considered in breeding programs. Thus, the identification of molecular markers linked to RSA traits is of special interest to the breeding community. The reported correlation between the RSA of seedlings and adult plants simplifies its assessment. Methods: In this study, a panel of 170 bread wheat landraces from 24 Mediterranean countries was used to identify molecular markers associated with the seminal RSA and related traits: seminal root angle, total root number, root dry weight, seed weight and shoot length, and grain yield (GY). Results: A genome-wide association study identified 135 marker-trait associations explaining 6% to 15% of the phenotypic variances for root related traits and 112 for GY. Fifteen QTL hotspots were identified as the most important for controlling root trait variation and were shown to include 31 candidate genes related to RSA traits, seed size, root development, and abiotic stress tolerance (mainly drought). Co-location for root related traits and GY was found in 17 genome regions. In addition, only four out of the fifteen QTL hotspots were reported previously. Conclusions: The variability found in the Mediterranean wheat landraces is a valuable source of root traits to introgress into adapted phenotypes through marker-assisted breeding. The study reveals new loci affecting root development in wheat.

Bioinspired Optimization of Germination Nutrients Based on Lactuca sativa Seedling Root Traits as Influenced by Seed Stratification, Fortification and Light Spectrums

“…With the advent of digital platforms, there are crop imaging programs that have been developed such as ImageJ software which was used to extract seminal root angles (Clark et al, 2011). Other root phenotyping platforms are the Automatic Root Imaging Analysis (ARIA) (Falk et al, 2020) and Root Reader 3D for five types of rice plant roots (Rufo, Salvi, Royo, & Soriano, 2020). RootNav2.0 is a deep learningbased automatic map reading of complex crop root system architecture (RSA) (Yasrab et al, 2019).…”

Regulation of Sixth Seminal Root Formation by Jasmonate in Triticum aestivum L.

“…Based on the information available in the literature, plants of the ‘Chinese Spring’ (CS) variety are characterized by the ability to produce a higher number of seminal roots compared to other studied varieties [ 4 , 6 , 7 , 54 , 55 ]. CS seedlings were shown to have on average 5.8 seminal roots [ 4 ].…”

Molecular Marker Technology for Crop Improvement

“…Genome-wide association studies (GWASs) have become a valuable tool in recent years as a complementary approach to biparental mapping, providing broader allelic coverage and higher mapping resolution. In this issue, GWASs were performed for the analysis of seminal roots in landraces of wheat and durum wheat from the Mediterranean basin [10,11], agronomic and quality traits in elite durum wheat [12], and for flowering time in maize inbred lines [13]. The studies of Roselló et al [10] and Rufo et al [11] pointed out the usefulness of the old germplasm to be used as genetic resources for improving drought-related traits in the breeding programs to broaden the genetic variability.…”

“…In this issue, GWASs were performed for the analysis of seminal roots in landraces of wheat and durum wheat from the Mediterranean basin [10,11], agronomic and quality traits in elite durum wheat [12], and for flowering time in maize inbred lines [13]. The studies of Roselló et al [10] and Rufo et al [11] pointed out the usefulness of the old germplasm to be used as genetic resources for improving drought-related traits in the breeding programs to broaden the genetic variability. Merida-García et al [12] combined a GWAS with a candidate gene approach to successfully identify gene clusters involved in important traits for wheat breeding.…”