Variation in Root Development Response of Napier Grass to Drought Stress

Global climate change and increasing agricultural activity are the main causes of biotic and abiotic stresses, which negatively affect the plant growth and crop yields. The plant root system is the first organ for sensing the soil moisture limitation; therefore root growth under elevated water deficit is an important indicator for plant’s drought tolerance. Although the previous studies focused on the morphological traits of Napier grasses under water stresses, the root growth changes due to drought levels remain largely unclear. In order to evaluate variation in root performance to respond to drought stress, four cultivars named "Cỏ voi thuần" (CVT), King grass, Packchong, and VA06 were grown for 10 days under drought conditions under polyethylene glycol 6000 (PEG6000): 0% PEG6000 as control, 5% PEG6000, 10% PEG6000, 15% PEG6000 and 20% PEG6000. As compared to control, the root growth of all cultivars was reduced under drought treatments; however, significant variation in the root development response to drought levels was found. Among Napier cultivars, "Cỏ voi thuần" expressed drought-tolerant genotypes. The information on the root length, diameter, surface area and volume of the cultivars reveals interesting guidelines for further studies to explore the mechanisms behind root adaptation of Napier grasses to drought.