Evaluation of Drought Tolerance and Susceptibility Indices of Rapeseed ‎Genotypes under Conditions of late Irrigation Interruption of Growing Season

In order to determine drought stress in the final stages of flowering up to 50% pods and pods until harvest tolerance in canola genotypes via yield-base stress tolerance indices, a split plot experiment has been conducted based on the randomized complete block design with three replications at the research farm of department of plant production and genetics, Agricultural Sciences and Natural Resources University of Khuzestan, Iran during 2020-2021. The main plots include three irrigation treatments: the control (without any interruption of irrigation), interruption of irrigation in the beginning of flowering stage (phenology code 60) to the formation of 50% pods (phenology code 75), and  interruption of irrigation in the stage of formation of pods until harvest (Phenology code 99) in the main plots. Also, the genotypes (Long pod, Aram, RGS 003, Jankom, Solar, Hayola 4815, Mahtab, Julius, Agamax, and Sala) are arranged in sub-plots with respect to irrigation treatments. They are reliable indices to identify drought tolerant rapeseed cultivars. Indices MP, GMP, and STI are the most suitable ones to evaluate drought stress tolerance in different treatments. The highest grain yield of control treatment belongs to Hayola 4815, Long pod, Solar genotypes (2093.8, 1791 and 1700 kg / ha), and the lowest to Jankum genotype (832.1 kg / ha), in flowering Stress up to 50% pods. The highest grain yield is observed in Hayola 4815 (1563.9 kg / ha) and Lon gpod (1150.9 kg / ha) and the lowest grain yield in Jankum and Mahtab genotype (540, 935.5 kg / ha).