Therefore, the identification, characterization, and development of crop varieties
with higher yield under low input conditions become a high breeding priority. The
traits involved in nutrient absorption, transport, and mobilization identified with the
recent plant molecular breeding tools like molecular linkage genetic maps, quantitative trait locus (QTL) mapping technologies, and high-throughput single nucleotide polymorphism (SNP) markers for its easiness and high precision (Feng et al.
2018). In addition now to advance plant breeding for NuUE, researchers have been
accessing massive online organized plant breeding and genomic resources including
quality genome sequences (Du et al. 2017) thick SNP maps (Ebana et al. 2012) free
databases of genomic information, and wide germplasm collections (Agrama et al.
2010). Several research works have been done with the help of plant molecular
breeding tools via the use of these available resources for the improvement of NPK
nutrients use efficiency. Currently in order to exploit the NuUE QTLs Pup1 is the
best model for exploiting the NuUE QTLs, which is evaluated in several genetic
backgrounds under field environments (Vinod and Heuer 2012).
4.1.3 Nitrogen Use Efficiency Improvement
As Nitrogen is the first an essential element for many aspects to improve plant
productivity higher amounts of nitrogen fertilizer has been using continuously,
which led to decreased nitrogen use efficiency (NUE) and increased environmental
pollution (Bouwman et al. 2002). A high rate of NH 3 losses up to 56% of the applied
N by volatilization was reported under several agroecosystems (Zaman et al. 2013).
Leaching of NO 3 by rain or irrigation water and its change into nonaccessible form
by microorganisms is another factor to reduce its uptake by crop plants. Nitrous
oxide (N 2 O) greenhouse gas formed due to extreme use of nitrogen fertilizer depletes
the ozone layer (Malyan et al. 2016). (Fig. 20.3) outlines the cycle of nitrogen in the
environment, that is, how N enters to soil and losses into the environment.
Exploring the available varieties by integrating classical plant breeding techniques with advanced biotechnological tools to increase NUE of a plant is a valuable
method. Several research efforts have been done to detect best N use-efficient
genotypes and superior grain yield (GY) parameters (Singh et al. 2015). In rice
crop (Obara et al. 2004), QTL regions linked with panicle weight and panicle
number on chromosome number 2 that includes a regulator gene (GS1) for glutamine
synthetase activity have been identified. Via applying this QTL rice plants have been
selected for their best panicle number, great in tillering capability, and overall
panicle weight in small N rates. Genomic regions, which are identified by different
researchers as shown in Table 20.1, associated with the high product at low nitrogen
amounts will be valuable in marker-assisted breeding for the release of improved
NUE crop variety within a short period.
20 The Potential of Biotechnology on Soil Quality by Minimizing Agrochemical. . .
413
with higher yield under low input conditions become a high breeding priority. The
traits involved in nutrient absorption, transport, and mobilization identified with the
recent plant molecular breeding tools like molecular linkage genetic maps, quantitative trait locus (QTL) mapping technologies, and high-throughput single nucleotide polymorphism (SNP) markers for its easiness and high precision (Feng et al.
2018). In addition now to advance plant breeding for NuUE, researchers have been
accessing massive online organized plant breeding and genomic resources including
quality genome sequences (Du et al. 2017) thick SNP maps (Ebana et al. 2012) free
databases of genomic information, and wide germplasm collections (Agrama et al.
2010). Several research works have been done with the help of plant molecular
breeding tools via the use of these available resources for the improvement of NPK
nutrients use efficiency. Currently in order to exploit the NuUE QTLs Pup1 is the
best model for exploiting the NuUE QTLs, which is evaluated in several genetic
backgrounds under field environments (Vinod and Heuer 2012).
4.1.3 Nitrogen Use Efficiency Improvement
As Nitrogen is the first an essential element for many aspects to improve plant
productivity higher amounts of nitrogen fertilizer has been using continuously,
which led to decreased nitrogen use efficiency (NUE) and increased environmental
pollution (Bouwman et al. 2002). A high rate of NH 3 losses up to 56% of the applied
N by volatilization was reported under several agroecosystems (Zaman et al. 2013).
Leaching of NO 3 by rain or irrigation water and its change into nonaccessible form
by microorganisms is another factor to reduce its uptake by crop plants. Nitrous
oxide (N 2 O) greenhouse gas formed due to extreme use of nitrogen fertilizer depletes
the ozone layer (Malyan et al. 2016). (Fig. 20.3) outlines the cycle of nitrogen in the
environment, that is, how N enters to soil and losses into the environment.
Exploring the available varieties by integrating classical plant breeding techniques with advanced biotechnological tools to increase NUE of a plant is a valuable
method. Several research efforts have been done to detect best N use-efficient
genotypes and superior grain yield (GY) parameters (Singh et al. 2015). In rice
crop (Obara et al. 2004), QTL regions linked with panicle weight and panicle
number on chromosome number 2 that includes a regulator gene (GS1) for glutamine
synthetase activity have been identified. Via applying this QTL rice plants have been
selected for their best panicle number, great in tillering capability, and overall
panicle weight in small N rates. Genomic regions, which are identified by different
researchers as shown in Table 20.1, associated with the high product at low nitrogen
amounts will be valuable in marker-assisted breeding for the release of improved
NUE crop variety within a short period.
20 The Potential of Biotechnology on Soil Quality by Minimizing Agrochemical. . .
413