Unravelling Roots for Drought Stress Defense in Cereal Crops

Drought is a complex problem with various underlying components still unexplored. Selecting number of morpho-physiological traits for indirectly improving yield under conditions of limited water availability, roots play a pivotal role in unravelling the drought escape mechanism. Root systems of terrestrial plants serve many important tasks among which anchorage of the plant and uptake of water plus nutrients are the most important ones and consequently ensures the water balance of the plant. Selection for root traits could lead to important benefits for improving and stabilizing yield under drought conditions, particularly in species with a limited capacity to adjust osmotically. The functional integration of root phenes is poorly understood so far. The information available on the genetic control of root traits in the field and their relationships with yield is limited, mainly due to the difficulty of measuring root characteristics in a large number of plants. Root scanning procedures are definitely good probes in understanding the root developmental architecture and anticipating above ground performance of the crop. Drought resistant genotypes are constantly revealing well developed root systems in all aspects on scanning like root volume, root branching, forks and crossings. Several root trait genes influencing the foraging capability have already been well studied, besides root QTL’s show great potential for marker assisted selection on large scale when root traits chosen contribute significantly to drought tolerance in the target environment of a crop. Root proteins with significant roles are mainly involved in ROS detoxification, energy metabolism, cell wall metabolism, and disease and defense responses. Plasma membrane proteins, regulators of signal transductions and ion channels also contribute to increased stress tolerance.