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

Rubén Rufo,Jose Soriano,Conxita Royo,Silvio Salvi

doi:10.3390/agronomy10050613

Rubén Rufo, Jose Soriano + Show 2 more

Open Access

https://doi.org/10.3390/agronomy10050613

Copy DOI

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.

Highlights

Wheat is the most widely cultivated crop in the world, covering around 219 million ha (Faostat2017, http://www.fao.org/faostat/)
The genotypes showed a low coefficient of variation (CV) with a narrow range of variation among traits, from 10.4 for seedin weight (SW) to
The current study evaluated root-related traits in a collection of Mediterranean bread wheat landraces representative of the variability existing for the species in the Mediterranean Basin [23]

Summary

Introduction

Wheat is the most widely cultivated crop in the world, covering around 219 million ha (Faostat2017, http://www.fao.org/faostat/). Global wheat demand is estimated to increase by 60% by the year 2050 [1], so wheat production will need to rise by 1.7% per year until Achieving this objective is a great challenge under the current climate change scenario, as the prediction models estimate a precipitation decrease of 25% to 30% and a temperature increase of 4 ◦ C to 5 ◦ C for the Mediterranean region [2]. 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.

Methods

Discussion

Conclusion