Role of Science, Technology and Innovation in Addressing …
67
The need to minimize such environmental impact from agricultural activities is
increasingly important to enhance viable and sustainable agricultural systems. The
carbon isotope discrimination has potential as a tool for screening and evaluating
large samples of cultivars with increased WUE under water-limited conditions.
3.2 Breeding for Drought Tolerance
One promising approach to face the projected impact of climate change on crops
is to integrate useful drought tolerance traits through genetic improvement into the
cultivated varieties. Recently, some techniques and plant criteria have been widely
used in screening for drought tolerance in plant breeding programs as the Drought
susceptibility index that based on the field performance and is used to compare
genotypes in terms of their ability to minimize the reduction in yield under droughtstressful compared with non-stressful environments. Chemical desiccation has been
suggested as an indirect simple method to simulate post-anthesis drought for smallgrain cereals [17]. Remote-sensing infrared thermometry (IR) was also proposed to
meet the criteria of a rapid, instantaneous, nondestructive, and monitoring wholeplant response to drought in the field [18, 19]. The technique is an indirect method
for assessing stomatal conductance of canopy leaves where canopies tend to warm
up with stomatal closure.
To select and evaluate plant cultivars that can withstand drought, measurement of
natural variations in the abundance of both light and heavy carbon stable isotopes
(
12 C and
13 C) in plant materials is increasingly being used by researches around the
world. This technique obviates the need for measurements of the water budgets of
a large number of plants during a large scale screening for WUE characteristics.
Under drought, less carbon (in the form of carbon dioxide), particularly
13 C from
the atmosphere is taken up by plants for growth because of plant stress, thus creating
a major variation in the natural isotopic ratios of
13 C and
12 C in plant materials. A
plant cultivar, which is resistant to water scarcity should display less depletion in
13 C compared with a susceptible cultivar. Such discrimination against
13 C (i.e., the
difference between
13 C and
12 C, expressed as delta G
13 C) in plant tissues (leaves
and grains) has been successfully used in the selection of drought-resistant barley,
wheat, rice and peanut (20) and (21) [20, 21]. Scientists have concluded that G
13 C in
plant leaves and grain is negatively related to WUE. Carbon isotope discrimination
(often abbreviated as (CID) measured in different plant parts at harvest can be used
as a historical account on how water availability varied during the cropping season
[22].
67
The need to minimize such environmental impact from agricultural activities is
increasingly important to enhance viable and sustainable agricultural systems. The
carbon isotope discrimination has potential as a tool for screening and evaluating
large samples of cultivars with increased WUE under water-limited conditions.
3.2 Breeding for Drought Tolerance
One promising approach to face the projected impact of climate change on crops
is to integrate useful drought tolerance traits through genetic improvement into the
cultivated varieties. Recently, some techniques and plant criteria have been widely
used in screening for drought tolerance in plant breeding programs as the Drought
susceptibility index that based on the field performance and is used to compare
genotypes in terms of their ability to minimize the reduction in yield under droughtstressful compared with non-stressful environments. Chemical desiccation has been
suggested as an indirect simple method to simulate post-anthesis drought for smallgrain cereals [17]. Remote-sensing infrared thermometry (IR) was also proposed to
meet the criteria of a rapid, instantaneous, nondestructive, and monitoring wholeplant response to drought in the field [18, 19]. The technique is an indirect method
for assessing stomatal conductance of canopy leaves where canopies tend to warm
up with stomatal closure.
To select and evaluate plant cultivars that can withstand drought, measurement of
natural variations in the abundance of both light and heavy carbon stable isotopes
(
12 C and
13 C) in plant materials is increasingly being used by researches around the
world. This technique obviates the need for measurements of the water budgets of
a large number of plants during a large scale screening for WUE characteristics.
Under drought, less carbon (in the form of carbon dioxide), particularly
13 C from
the atmosphere is taken up by plants for growth because of plant stress, thus creating
a major variation in the natural isotopic ratios of
13 C and
12 C in plant materials. A
plant cultivar, which is resistant to water scarcity should display less depletion in
13 C compared with a susceptible cultivar. Such discrimination against
13 C (i.e., the
difference between
13 C and
12 C, expressed as delta G
13 C) in plant tissues (leaves
and grains) has been successfully used in the selection of drought-resistant barley,
wheat, rice and peanut (20) and (21) [20, 21]. Scientists have concluded that G
13 C in
plant leaves and grain is negatively related to WUE. Carbon isotope discrimination
(often abbreviated as (CID) measured in different plant parts at harvest can be used
as a historical account on how water availability varied during the cropping season
[22].