Oilseed Rape Cultivars Show Diversity of Root Morphologies with the Potential for Better Capture of Nitrogen

László Kupcsik,Julien Louvieaux,Loïc Haelterman,Malcolm Bennett,Philippe Nacry,Pascal Tillard,Hugues De Gernier,Claudia Chiodi,Christian Hermans,Craig J Sturrock,Taraka Ramji Moturu

doi:10.3390/nitrogen2040033

Abstract

The worldwide demand for vegetable oils is rising. Oilseed rape (Brassica napus) diversifies cereal dominated crop rotations but requires important nitrogen input. Yet, the root organ is offering an untapped opportunity to improve the nitrogen capture in soil. This study evaluates three culture systems in controlled environment, to observe root morphology and to identify root attributes for superior biomass production and nitrogen use. The phenotypic diversity in a panel of 55 modern winter oilseed rape cultivars was screened in response to two divergent nitrate supplies. Upon in vitro and hydroponic cultures, a large variability for root morphologies was observed. Root biomass and morphological traits positively correlated with shoot biomass or leaf area. The activities of high-affinity nitrate transport systems correlated negatively with the leaf area, while the combined high- and low-affinity systems positively with the total root length. The X-ray computed tomography permitted to visualize the root system in pipes filled with soil. The in vitro root phenotype at germination stage was indicative of lateral root deployment in soil-grown plants. This study highlights great genetic potential in oilseed rape, which could be manipulated to optimize crop root characteristics and nitrogen capture with substantial implications for agricultural production.

Highlights

Agriculture is facing the challenge of producing more food while reducing the negative environmental impact of nitrogen (N) fertilization
The Nitrogen Use Efficiency (NUE) is a combination of the Nitrogen Uptake Efficiency (NUpE)—the ability of the crop to take up N from the soil and the Nitrogen Utilization Efficiency (NUtE)—the ability of the crop to utilize the absorbed N for producing yield [6,7]
This study explores the natural variation of root morphology in response to the nitrate supply among a diversity panel of 55 modern winter oilseed rape cultivars

Summary

Introduction

Agriculture is facing the challenge of producing more food while reducing the negative environmental impact of nitrogen (N) fertilization. Synthetic N fertilizers come with elevated prices. Such costs are economical and environmental, as fertilizers cause groundwater pollution by nitrate leaching [1,2] and air pollution by nitrous oxide emission [3,4]. Breeding crops with greater Nitrogen Use Efficiency (NUE) is one solution to achieve that goal [5]. It is calculated as the ratio of crop yield to N units available. Methods for phenotyping crop root system architecture can be challenging

Methods

Results

Conclusion