Evaluation of forage yield and root characteristics of tall fescue (Festuca arundinacea) genotypes under drought stress

Drought stress represents the most limiting factors for agricultural productivity in arid and semiarid region of the world. This research was conducted to evaluate the effect of drought stress on root morphological attributes and dry matter yield in tall fescue Festuca arundinacea. Twelve genotypes were assessed under three levels of moisture regime (non-stress، moderate drought stress and severe drought stress) according to a factorial experiment based on a completely randomized design with 3 replications in 2011. The genotypes were grown in the plastic pots (60×12 cm) and root traits were measured at 0-30 and 30-60 cm depths. Results indicated that the effect of moisture regime، genotype and their interaction were significant for all of the measured traits. Moderate drought led to significant increase in root dry weight، but severe drought did not affect it. With augmentation of the drought stress، the root/shoot ratio increased about 30 and 54% in 0-30 cm and 30-60 cm depth of root، respectively. Moderate and severe drought led to 15% and 30% decrease in plant dry weight، respectively. Some genotypes such as 21P produced high dry matter yield and expanded root system which can be used for future breeding programs.