A new approach for quantifying and scaling the drought resistance of crop plants during vegetative growth phase

Abstract All known methods for evaluating crops resilience under water deficit stress are relative and need a reference experiment, and up till now no method is available for quantification and scaling plants performance in this harsh habitat. In this study, an equation was established for quantifying the absolute drought resistance (ADRI) of crops plants with a scale of 0.0 to 100. This approach was based on datasets of 5 parameters: chlorophyll, RWC, drought period, soil moisture content and temperature index of 14 species (43 cultivars /treatments), and a practical experiment was executed to test this approach. Application of the new graduation displayed a reasonable ADRI values for the examined crops. Rice ( Oryza sativa L.) appeared to be the most drought sensitive species with a value of 3.48–5.20., whereas the xerophytic species Aloe vera L. manifested the highest value (90.03). Noteworthy, this approach was also sensitive to the extent of stress and cultivar type, for example Aloe vera achieved ADRI value of 84.52 only at severe water deficit. The order of 14 evaluated species depending on their ADRI values were: Aloe > Opuinta > Toothbrush > Date palm > Cassava > Grape vine > Sorghum > Lotus > Barley > Wheat > Maize > Banana > Rice. Practical experiment supported the rightness of this approach with ADRI values of 77.5 and 18.5 for Aloe vera and Zea maize , respectively. This new approach for quantification of drought resistance would be a time and cost effective guide for farmers, plant breeders and physiologist.