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raw material for agro-ecosystems to cope with climate change
because it can provide traits for plant breeders and farmers to
select resilient, climate-ready crop germplasm (Ortiz 2011). A
third strategy involves improving seed varieties to develop new
traits, such as drought resistance (Pray et  al. 2011). One vari-
ant of this third strategy has received considerable attention
recently: that is employing marker-assisted breeding (MAB)
approaches to develop seeds that are well adapted to climate
change. The second variant of this strategy is innovation in plant
breeding to develop crop varieties that are more resilient to cli-
mate change. The objective of molecular plant breeding is to
accumulate favourable alleles that contribute to stress tolerance
in a plant genome. In this chapter, we are addressing the role of
molecular plant breeding in abiotic constraints to enhance the
crop productivity.
Genes that confer stress resistance can be sourced from wild
relatives of crops that are held in gene banks or in the live habi-
tats of water deficit or excess, extreme temperature and salin-
ity that have evolved to cope with those conditions. Although
some progress has been made through conventional breeding,
but due to the complex nature of abiotic stress tolerance unde-
sirable genes are also transferred along with desirable traits
that limit the transfer of favourable alleles from diverse genetic
resources. MAB is an emerging area that involves transfer of
superior genes or alleles, where they were tightly linked to a
particular trait into elite genotypes of locally adopted germ-
plasm. However, genetic engineering (GE) involves transferring
useful genes or alleles across different species from the ani-
mal or plant kingdoms. As a result, biotechnology approaches
offer novel strategies for producing suitable crop genotypes that
are able to resist drought, high temperature, submergence and
salinity stresses. The key strategies where genetic enhancement
for stress tolerance has led to crop improvement are outlined in
this section.
17. 2 Key biotechnological strategies for improving
stress tolerance
Molecular
breeding
approach
1. The development of genomic resources such as molecu-
lar markers, including simple sequence repeats (SSRs),
single-nucleotide polymorphisms (SNPs) and marker
genotyping platforms
2. The development of bi-parental mapping populations by
using genetically and phenotypically diverse parental
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