Agriculture Reference
In-Depth Information
Having several defi nitions over the history of crop production, landraces
are heterogeneous crop populations possessing genotypes specifi c to a giv-
en region, with great adaptability to the natural environment and agricul-
tural practices of that region [37]. These varieties generally have not been
optimized for yield performance alone, but are known to have higher yield
stability and when produced under local stressed conditions, they are able
to cope, producing moderate yields compared to modern cultivars that are
unable to tolerate certain stresses and result in crop failure [37,38]. Breed-
ing programs thus need to be developed that examine potential varieties
more suited to low-yielding conditions, in which varieties would be select-
ed that have more advantageous adaptations in stress conditions such as
delayed leaf senescence, improved nutrient economy, local environmental
fi tness, consistent yield, and pest/disease resistance, thus increasing the
profi tability of sustainable low-input systems. The importance in shifting
the paradigm of modern agriculture from high- to low-input is becoming
more urgent as the human population continues to increase, at the same
time crucial fi nite resources have or are reaching peak production and will
inevitably begin to decline. Breeding for low-yielding and variable stress
conditions is more complex than breeding for uniform, controlled, highly
productive systems, but absolutely necessary to feed the growing popula-
tion under diminishing global resources.
11.4.2 WATER
Besides the concerns of producing food for the growing population on
land that is increasingly becoming more limited, we are also at a histori-
cal moment as the supply of available fresh water, oil, and phosphorus
are reaching their peaks, all of which are key elements of modern pro-
duction systems. Agriculture is the largest consumer of water worldwide,
accounting for 70% of the global demand for fresh water. Currently, 1.2
billion people live and produce food in areas affected by drought, and this
number is expected to rise as the demand for water increases [20]. Water
demand is a function of several aspects including population density, diet,
and agricultural practices of any given region. Thus as the population in-
creases, the demand for water will also grow. With the projected increase
