Agriculture Reference
In-Depth Information
FIGURE 4:
Proposed strategy for improving N use efficiency in crops. This strategy is
built around two main agronomic and genetic studies conducted in parallel. Each of these
two main studies is divided into a subset of approaches strongly interacting with each other
within and across them. It will be necessary to integrate current knowledge in agronomy,
molecular physiology, eco-physiology and genetics to guide, develop and integrate novel
methods and concepts for improving NUE in crops. This knowledge development and
integration can be performed through the use of quantitative genetics for QTL and candidate
gene detection (KD.1), through the exploitation of all the 'omics' databases using a systems
biology approach (KD.2) and through the use of agronomic databases gathering all the
information concerning plant performance under various environmental scenarios (KD3).
The basis of this knowledge is represented by: (1) the numerous whole plant physiology
studies performed over the last two decades on both model and crop species (KF.1) ;
(2) the studies aimed at identifying the influence of N fertilization on crop growth and
development and its physiology either under organic (KF2) or organic N nutrition (KF3) ;
(3) through the exploitation of genetic variability of a given species using different modern
and ancient genotypes, landraces, lines, hybrids originating from different parts of the
world. The primary goal of the genetic studies is to provide breeders with markers genes or
loci aimed at selecting varieties more efficient at utilizing N, identified through the use of
quantitative genetics (KD.1), mutagenesis (G.1) and genetic engineering (G.2) for further
commercialization by breeding companies (O.1). The aim of the agronomic studies is to
provide tools for breeders and agronomists to create and evaluate new varieties in cropping
systems under low and adequate N input in conventional or organic farming systems. To
achieve this it will be necessary to identify key agronomic traits that can be use to predict
plant performance under low or high N input and according to various environmental
conditions (A.1). Plant performance could also be predicted and monitored through the
use of monitoring tools or sensors (A.2 = metabolic, enzymatic and molecular markers
for NUE; see [109] for details) and through the development of plant and crop modeling
approaches integrating agronomic, physiological and molecular data (G+A) [213]. These
monitoring tools and models will also help the farmers to rationalize N fertilization when
integrated into decision support systems (A.3). In addition the knowledge gained from
these complementary studies will be useful to the scientific community to improve our
understanding of N assimilation by plants both at the whole plant and canopy levels (O.2).
The boxes shaded in dark grey indicate where significant progress has been made in the
area. Those in pale grey indicate that work is still currently being actively performed.
Those in white indicate the research area for which results and data are scarce or missing.
