In an article entitled, “Control of root system architecture by DEEPER ROOTING 1 increases rice yield under drought conditions” published online in the 4th of August issue of Nature Genetics, Yusaku Ugaand 18 other associates affiliated to the International Center for TropicalAgriculture (CIAT), Colombia, one more Institute in Colombia and two in Japan have demonstrated that modification of root system architecture improves drought tolerance. This was achieved by incorporating a rice quantitative trait locus, DRO1 (Deeper Rooting 1) conditioning root growth angle. DRO1 causes asymmetric root growth and as a result of which there is downward bending of the root in response to gravity. The team crossbred IR64, a high-yielding, but short-rooted and drought-prone commercial rice variety, with a deep-rooting upland rice variety from the Philippines, called Kinandang Patong. The scientists then combined the high yields of IR64, with the fully-functional DRO1 gene in Kinandang Patong.
The resulting plants had roots that were able to reach more than twice as deep as those of IR64. When tested under simulated conditions of moderate drought, IR64 yields were lessened by almost 60%, while the crossbreeds suffered only a 10% yield loss. Under extreme drought, IR64 completely failed, but the newly bred rice plants continued to produce grain – about 30% of the yield of unstressed rice plants growing in normal conditions.