Phenotyping pipeline reveals major seedling root growth QTL in hexaploid wheat.

Jonathan A Atkinson,Jacques Le Gouis,Julie King,M John Foulkes,Michael P Pound,Luzie U Wingen,Malcolm J Bennett,Simon Griffiths,Darren M Wells,Oorbessy Gaju,Marcus Griffiths

doi:10.1093/jxb/erv006

Abstract

Seedling root traits of wheat (Triticum aestivum L.) have been shown to be important for efficient establishment and linked to mature plant traits such as height and yield. A root phenotyping pipeline, consisting of a germination paper-based screen combined with image segmentation and analysis software, was developed and used to characterize seedling traits in 94 doubled haploid progeny derived from a cross between the winter wheat cultivars Rialto and Savannah. Field experiments were conducted to measure mature plant height, grain yield, and nitrogen (N) uptake in three sites over 2 years. In total, 29 quantitative trait loci (QTLs) for seedling root traits were identified. Two QTLs for grain yield and N uptake co-localize with root QTLs on chromosomes 2B and 7D, respectively. Of the 29 root QTLs identified, 11 were found to co-localize on 6D, with four of these achieving highly significant logarithm of odds scores (>20). These results suggest the presence of a major-effect gene regulating seedling root vigour/growth on chromosome 6D.

Highlights

Bread wheat (Triticum aestivum L.) is a crop of global importance accounting for ~20% of all calories consumed worldwide (Food and Agriculture Organization of the United Nations, 2013)
A root phenotyping pipeline, consisting of a germination paperbased screen combined with image segmentation and analysis software, was developed and used to characterize seedling traits in 94 doubled haploid progeny derived from a cross between the winter wheat cultivars Rialto and Savannah
The Reduced height (Rht) genes, which control shoot height in wheat and are present in many modern cultivars, have been reported to reduce root proliferation (Bai et al, 2013). This has prompted the proposal that optimization of root system architecture (RSA) should form the basis of a second Green Revolution to produce the increase in below-ground resource capture and yield required to meet the needs of the increasing global population (Lynch, 2007)

Summary

Introduction

Bread wheat (Triticum aestivum L.) is a crop of global importance accounting for ~20% of all calories consumed worldwide (Food and Agriculture Organization of the United Nations, 2013). Breeding and selection programmes have not directly considered RSA to date, mainly due to the difficulty in observing root traits in soil (Waines and Ehdaie, 2007). The Reduced height (Rht) genes, which control shoot height in wheat and are present in many modern cultivars, have been reported to reduce root proliferation (Bai et al, 2013) This has prompted the proposal that optimization of RSA should form the basis of a second Green Revolution to produce the increase in below-ground resource capture and yield required to meet the needs of the increasing global population (Lynch, 2007). Optimization of RSA may be a promising avenue to enhance nitrogen (N) uptake efficiency and reduce N fertilizer requirements with associated environmental and economic benefits (Foulkes et al, 2009)

Methods

Results

Conclusion