Evaluation of terminal drought tolerance in Foxtail millet (Setaria italica) accessions

To evaluate the tolerance of 13 accessions of foxtail millet to terminal drought stress, two separate experiments were carried out at Agricultural Research Station of Birjand, Southern Khorasan, Iran, in 2005 and 2006, using randomized complete block design with three replications. In first experiment (stress condition) irrigation was stopped at the beginning of flowering stage (10% panicle emergence) and in second experiment (non-stress condition) the irrigation interval was seven days. Agronomic traits including; panicle number.m-2, grain number.panicle-1, 1000 grain weight, grain yield and dry forage yield were measured. Results showed that drought stress reduced all measured traits and grain yield was affected the most. Accessions 15-143, from Southern Khorasan and, and 15-24, from Yazd, had higher grain yield (1544.8 and 1468. kg.ha-1, respectively) and dry forage yield (3522.3 and 2653 kg.ha-1, respectively). Evaluation of foxtail millet accessions for tolerance to terminal drought using MP, TOL, SSI, GMP, STI and HARM and their correlation with grain yield and dry forage yield in stress and non-stress conditions showed that HARM, GMP and STI were suitable indices for identifying drought tolerant accessions. Three dimensions graph study showed that accessions 15-143 and 15-131, from Southern Khorasan, and 15-24, from Yazd, had higher grain yield and were tolerant to terminal drought stress.