nucleic acid and in silico similarity search analysis, four endophytic bacteria isolates
identified and showed remarkable phosphate solubilizing activity (Seung et al.
2013). These PGPB isolates demonstrated their positive effects on development
and growth in rice crops. Hence, the potential of biotechnology has an unlimited
impact on characterization, and identification, and improvement of phosphorous
solubilizing microorganism (PSM) and nitrogen-fixing bacteria for efficient nutrient
uptake as well as promoting plants growth when they applied as biofertilizer in
cultivated soils by confirming sustainable agriculture within a short period and
decrease of chemical fertilizers pollution on the soil.
4.1.2 Plant Molecular Breeding for Soil Quality Improvement
Quantitative traits are genetically influenced by many genes and each gene has a
relatively small influence on the phenotype but is mainly controlled by environmental factors (Buckler et al. 2009). A chromosomal region related to a marker that
affects a quantitative trait was defined as a quantitative trait locus (QTL)
(Geldermann 1975). In the period 1980–1990 molecular maps were constructed
for various plant species. The complication of molecular map construction has
developed from the RFLP maps of the 1980s to PCR-based markers of the 1990s
to more integrated maps, due to the result of using diverse types of molecular
markers including genic markers, over the past decade. Linkage maps have been
used in gene mapping for major genes and QTL. In addition to mapping, a markertrait association for NUE through quantitative real-time polymerase chain reaction
(RT-PCR) technology has been using (Sinha et al. 2018).
There is a crucial demand for the release of nutritious, high-yielding, resource
use-efficient, and different stress-tolerant crop varieties, especially in cereal crops,
which are the main source of human, to go with the incredible human population
growth. The yields of cereal grain had seen notable progress in the green revolution.
This enhancement in production was mainly realized by high-input-responsive
varieties demanding more synthetic fertilizers and pesticides. This kind of approach
adversely affected our sustainable agricultural system in the past three to four
decades. So, now it is a time to find a way that yields can be improved with limited
applied inputs, especially the inputs adversely affecting our sustainable agriculture.
In experimental managed plots, Nitrogen (N) fertilizer recovery in a 1 year averaged
57% for wheat, 65% for maize, and 46% for rice (Xu et al. 2015). However, in
farming practices did not reflect the efficiencies got in the experimental plot. For
example, N retrieval effectiveness on average ranges from 30 to 55% under irrigated
conditions and from 20 to 30% for farmer practice fields under rainfed environments
(Liu et al. 2016).
Due to these limitations of the crop in the uptake of the given fertilizer inputs,
breeding crop cultivars for the improvement of nutrient use efficiency (NuUE)
becomes a prerequisite to minimize the quantity of nutrient application goes to
ecosystems, reduce fertilizer application, decreasing input costs, and improving
cereal yield with assuring sustainable agriculture via maintaining soil quality.
412
S. Abera
identified and showed remarkable phosphate solubilizing activity (Seung et al.
2013). These PGPB isolates demonstrated their positive effects on development
and growth in rice crops. Hence, the potential of biotechnology has an unlimited
impact on characterization, and identification, and improvement of phosphorous
solubilizing microorganism (PSM) and nitrogen-fixing bacteria for efficient nutrient
uptake as well as promoting plants growth when they applied as biofertilizer in
cultivated soils by confirming sustainable agriculture within a short period and
decrease of chemical fertilizers pollution on the soil.
4.1.2 Plant Molecular Breeding for Soil Quality Improvement
Quantitative traits are genetically influenced by many genes and each gene has a
relatively small influence on the phenotype but is mainly controlled by environmental factors (Buckler et al. 2009). A chromosomal region related to a marker that
affects a quantitative trait was defined as a quantitative trait locus (QTL)
(Geldermann 1975). In the period 1980–1990 molecular maps were constructed
for various plant species. The complication of molecular map construction has
developed from the RFLP maps of the 1980s to PCR-based markers of the 1990s
to more integrated maps, due to the result of using diverse types of molecular
markers including genic markers, over the past decade. Linkage maps have been
used in gene mapping for major genes and QTL. In addition to mapping, a markertrait association for NUE through quantitative real-time polymerase chain reaction
(RT-PCR) technology has been using (Sinha et al. 2018).
There is a crucial demand for the release of nutritious, high-yielding, resource
use-efficient, and different stress-tolerant crop varieties, especially in cereal crops,
which are the main source of human, to go with the incredible human population
growth. The yields of cereal grain had seen notable progress in the green revolution.
This enhancement in production was mainly realized by high-input-responsive
varieties demanding more synthetic fertilizers and pesticides. This kind of approach
adversely affected our sustainable agricultural system in the past three to four
decades. So, now it is a time to find a way that yields can be improved with limited
applied inputs, especially the inputs adversely affecting our sustainable agriculture.
In experimental managed plots, Nitrogen (N) fertilizer recovery in a 1 year averaged
57% for wheat, 65% for maize, and 46% for rice (Xu et al. 2015). However, in
farming practices did not reflect the efficiencies got in the experimental plot. For
example, N retrieval effectiveness on average ranges from 30 to 55% under irrigated
conditions and from 20 to 30% for farmer practice fields under rainfed environments
(Liu et al. 2016).
Due to these limitations of the crop in the uptake of the given fertilizer inputs,
breeding crop cultivars for the improvement of nutrient use efficiency (NuUE)
becomes a prerequisite to minimize the quantity of nutrient application goes to
ecosystems, reduce fertilizer application, decreasing input costs, and improving
cereal yield with assuring sustainable agriculture via maintaining soil quality.
412
S. Abera