Climate Change Adaptation - Climate Resilient Agriculture for Ensuring Food Security - page 221

12.1.4 Developing
Climate-Ready Crops

12.1.5 Drought-Tolerant Varieties

Different agronomic adaptation practices are
applicable to different farming systems and agro-
climatic zones, including drought tolerance for
adaptation to climate change. Many research
institutions have developed various crop varieties
suitable for specifi c climatic zones. For instance,
new rice varieties with acceptable grain quality
and yield and shorter growing duration need to be
developed or introduced into rice-growing areas.
The adoption of direct seeding pre-germinated
seed, either by broadcasting or drum seeding,
into fl ooded paddy fi elds can reduce the crop
cycle by 10-45 days. Farmers need to be linked
to leading research institutions to get certifi ed
seeds to increase production under changing
rainfall regimes.
Fifty new maize hybrids and open-pollinated
maize varieties have been developed and provided
to seed companies and NGOs for dissemination,
and several of them have reached farmers' fi elds.
These drought-tolerant maize varieties produce
20-50 % higher yields than other maize varieties
under drought conditions. Farmers choose their
crops according to the climate in which they
operate. For example, in Sahelian West Africa,
farmers prefer drought-tolerant crops such as
sorghum and cowpea (Kurukulasuriya and
Mendelsohn 2006 ). Moreover, introduction of
improved crop varieties should consider the local
community's eating habits, cultural practices,
agroecological conditions, and markets.
Several horticultural crop varieties have been
released which are resistant to abiotic stresses
such as heat and moisture (Table 12.1 ).

Development of new crop varieties with higher
yield potential and resistance to multiple stresses
(drought, fl ood, salinity) will be the key to main-
tain yield stability. Improvement in germplasm of
important crops for heat-stress tolerance should
be one of the targets of breeding program.
Similarly, it is essential to develop tolerance to
multiple abiotic stresses as they occur in nature.
The abiotic stress tolerance mechanisms are quan-
titative traits in plants. Germplasm with greater
oxidative stress tolerance may be exploited as oxi-
dative stress tolerance is one example where
plant's defense mechanism targets several abiotic
stresses. Similar to the research efforts on conver-
sion of rice from C3 to C4 crop, steps should be
taken for improvement in radiation-use effi ciency
of other crops as well. Improvement in water-use
and nitrogen-use effi ciencies is being attempted
since long. These efforts assume more relevance
in the climate change scenarios as water resources
for agriculture are likely to dwindle in future.
Nitrogen-use effi ciency may be reduced under the
climate change scenarios because of high tem-
peratures and heavy precipitation events causing
volatilization and leaching losses. Apart from this,
for exploiting the benefi cial effects of elevated
CO 2 concentrations, crop demand for nitrogen is
likely to increase. Thus, it is important to improve
the root effi ciency for mining the water and
absorption of nutrients. Exploitation of genetic
engineering for 'gene pyramiding' has become
essential to pool all the desirable traits in one
plant to get the 'ideal plant type' which may also
be 'adverse climate-tolerant' genotype.
Farmers need to be provided with cultivars
with a broad genetic base. Their adaptation pro-
cess could be strengthened with availability of
new varieties having tolerance to drought, heat,
and salinity and thus minimize the risks of cli-
matic aberrations. Similarly, development of
varieties is required to offset the emerging
problems of shortening of growing season and
other vagaries of production environment.
Farmers could better stabilize their production
system with basket of technological options.

12.1.6 Promoting Use
of Biotechnology

Biotechnology is an important tool for the
development of genetic resources with greater
adaptive capacity to cope with changing environ-
ments. It has huge potential for combating vul-
nerabilities in crops, livestock, and fi sheries.
Research and promotion of higher carbon (C4)
pathways in low carbon (C3) plants and genetic