Geoscience Reference
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rising sea levels decrease available arable land and fresh water
sources. This condition requires the need for an agriculture that
truly conserves both water and land, and still gives a higher
yield to feed the growing population. Biotechnology can be
employed to generate an agricultural system that will be more
water-efficient in the large-scale production methods.
Keeping the above information in view, the solutions that
facilitate the adaptation of crops to these abiotic stresses
(drought, salinity, etc.) need to be developed. The conventional
approaches to reduce the effects of these abiotic stresses involve
selecting and growing stress-resistant crops that can tolerate
harsh conditions on marginal lands. Examples of such crops
include cassava, millet and sunflower (Manavalan et al., 2009).
Tissue culture and breeding are also being used to cross stress-
tolerant crops with high-yielding species, generating stress-tol-
erant high-yielding hybrids (Ruane et al., 2008). Although the
biotechnology community generally focuses on either molecu-
lar breeding or genetic engineering approaches, it is evident
that there is a need to target complex problems caused by dif-
ferent stresses using integrated biotechnology approaches. As
the whole genome sequence of plant, physical maps, genet-
ics and functional genomics tools are becoming increasingly
available, integrated approaches using molecular breeding and
genetic engineering offer new opportunities for improving
stress resistance (Manavalan et  al., 2009). Hence, an outline
for breeding a plant for the abiotic stress should incorporate
conventional breeding and germplasm selection, elucidation of
specific molecular control mechanisms in tolerant and sensitive
genotypes, biotechnology-oriented improvement of selection
and breeding procedures (functional analysis, marker probes
and transformation with specific genes) and improvement and
adaptation of current agricultural practices (Wang et al., 2003).
Activation and regulation of specific stress-related genes
form the basis of the control mechanisms for abiotic stress
tolerance (Table 6.1). Genetically engineered plants are based
on different stress mechanisms, like metabolism, regula-
tory controls, ion transport, antioxidants and detoxification,
late embryogenesis abundance, heat shock process and heat
proteins (Wang et  al., 2003). A number of high-yielding GM
crops tolerant to abiotic stress have already been made avail-
able, some of which include tobacco (Hong et  al., 2000),
Arabidopsis thaliana and Brassica napus (Jaglo et  al., 2001),
tomato (Hsieh et  al., 2002; Zhang and Blumwald, 2002), rice
(Yamanouchi et  al., 2002), maize, cotton, wheat and oilseed
rape (Yamaguchi and Blumwald, 2005). As drought and water
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