Investigation of Durum Wheat Cultivars Based on Heat Tension Evolution Indices in Mazandaran

In order to investigate the effect of terminal heat tension on yield and grain yield components of durum wheat cultivars (Triticum durum Desf.), the present field experiments were conducted in two sowing time (optimum sowing date and late sowing date). Seven durum wheat cultivars (Yavaros, Dena, Karkhe, Aria, Behrang, Saji and Zardak) were investigated in randomized complete blocks design with four replications in Islamic Azad University of Qaemshahr branch in Mazandaran province in 2009-10, 2010-11 and 2011-12 three cropping seasons. Analysis of variance showed the effect of cultivar on spike weight and grain yield was significant, while the interaction of year in cultivar was significant for spike weight trait, but it was not significant for grain yield. The amount of spike weight loss under tension conditions was not the same for the studied cultivars, which proves the importance of selecting the insensitive cultivar to the heat tension. The investigation of tension indices showed that stress tolerance indices (STI), mean of productivity (MP) and geometric mean productivity (GMP) in optimal conditions and heat tension conditions, with grain yield, had a significant correlation (α ≤ 1%), so they were suggested for the selection of insensitive cultivars. Behrang cultivar with an average grain yield of 5310 kilogram per hectare in optimal conditions, and by 16.9 percent reduction in tension conditions; had the highest amounts of STI, MP and GMP indices and was proposed as the most appropriate cultivar for cultivation in Mazandaran region.