Study of heat stress on rice cultivars grain milling quality in North Khuzestan

An experiment Was carried out Study of heat stress on rice cultivars grain milling quality of Khuzestan province in a split-plot arrangement using randomized complete blocks design with three replications in 2006 and 2007 cropping seasons at Shavoor Agricultural Research Station, Dependent in Research Center of Agricultural and Natural Resources of Khuzestan. For exposing rice cultivars to different higher temperature regimes, main plot was assigned to three sowing dates from 5 May with 20 days' intervals and cultivars; Hoveizeh, Hamar (heat tolerance) Ghermez Anbori, Champa (heat sensitive) and Danial (relatively heat tolerant) were randomized in sub-plots. The results of combined analyses showed that was a significant different in planting date by variety interaction in all of trades. On the other hand, the related temperature condition, varieties had different reaction. The highest of grain elongation obtained in Ghermez Anbori, Danial and third sowing date. The elongation ratio was higher in third; second sowing date and Ghermez Anbori. The heat tolerant cultivars had highest Gel consistency (Gc) and Amylose content (Ac). The highest Gelatinization temperature (Gt) obtained in third sowing date.