A genetic relationship between nitrogen use efficiency and seedling root traits in maize as revealed by QTL analysis.

Jianchao Liu,Guohua Mi,Qingchun Pan,Pengcheng Li,Fanjun Chen,Hongguang Cai,Riliang Gu,Fusuo Zhang,Lixing Yuan,Zhigang Liu

doi:10.1093/jxb/erv127

Jianchao Liu, Guohua Mi + Show 8 more

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https://doi.org/10.1093/jxb/erv127

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Abstract

That root system architecture (RSA) has an essential role in nitrogen acquisition is expected in maize, but the genetic relationship between RSA and nitrogen use efficiency (NUE) traits remains to be elucidated. Here, the genetic basis of RSA and NUE traits was investigated in maize using a recombination inbred line population that was derived from two lines contrasted for both traits. Under high-nitrogen and low-nitrogen conditions, 10 NUE- and 9 RSA-related traits were evaluated in four field environments and three hydroponic experiments, respectively. In contrast to nitrogen utilization efficiency (NutE), nitrogen uptake efficiency (NupE) had significant phenotypic correlations with RSA, particularly the traits of seminal roots (r = 0.15-0.31) and crown roots (r = 0.15-0.18). A total of 331 quantitative trait loci (QTLs) were detected, including 184 and 147 QTLs for NUE- and RSA-related traits, respectively. These QTLs were assigned into 64 distinct QTL clusters, and ~70% of QTLs for nitrogen-efficiency (NUE, NupE, and NutE) coincided in clusters with those for RSA. Five important QTLs clusters at the chromosomal regions bin1.04, 2.04, 3.04, 3.05/3.06, and 6.07/6.08 were found in which QTLs for both traits had favourable effects from alleles coming from the large-rooted and high-NupE parent. Introgression of these QTL clusters in the advanced backcross-derived lines conferred mean increases in grain yield of ~14.8% for the line per se and ~15.9% in the testcross. These results reveal a significant genetic relationship between RSA and NUE traits, and uncover the most promising genomic regions for marker-assisted selection of RSA to improve NUE in maize.

Highlights

Nitrogen (N) is quantitatively the most important mineral yield significantly
nitrogen use efficiency (NUE)-related traits were evaluated in field experiments across four environments, including plant biomass (GY, stover yield (SY), and harvest index (HI)), plant N concentration (GNC, stover nitrogen concentration (SNC), and nitrogen harvest index (NHI)), and N efficiency (NUE, nitrogen uptake (Nup), nitrogen uptake efficiency (NupE), and nitrogen utilization efficiency (NutE))
Under low N (LN) conditions, grain yield (GY) of both lines decreased by 9.5% and SY by 13.6%, but the differences were not significant

Summary

Introduction

Nitrogen (N) is quantitatively the most important mineral yield significantly. N fertilizer production consumes nutrient for plant growth and development. In the past dec- ~1% of the world’s total annual energy supply and results in ades application of synthetic N fertilizer has increased crop significant amounts of greenhouse gas emissions Zhang et al, 2013). The overuse of N fertilizer in many regions of the world causes serious damage to the environment, including soil acidification, and water and air pollution (Galloway et al, 2008; Guo et al, 2010; Liu et al, 2013). To simultaneously ensure food security and environmental quality, it is important to cultivate crops that are able to uptake and utilize N efficiently (Good and Beatty, 2011)

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