Evaluation of different levels of Irrigation on yield and qualitative properties of two rice varieties (Tarom and Shiroodi)

Quality of produce is as much important as quantity in all stages of life and particularly in direct consumption of commodities. In order to evaluate some rice grain physicochemical properties in different irrigation regimes in two varieties (Tarrom and Shiroodi)، a field experiment was carried out on randomized complete block design at rice research institute of Mazandaran in 2010. Treatments includes five irrigation regimes، viz.، T1: permanent flooding with 3-5cm height throughout growing season، T2: irrigation with 5cm height after disappearing water from soil surface، T3: irrigation with 5cm height 2 day after disappearing water from soil surface، T4: irrigation with 5cm height 5 day after disappearing water from soil surface and T5: permanent saturation during growth period، with three replication. In each treatment، yield and some grain quality parameters were measured. The statistical analysis showed that، there was a significant differences in yield between treatments (α<0. 01)، with highest yield in continuously flooded treatment، 4210kg/ha and 6799. 7kg/ha in Tarom and Shiroodi، respectively. There were significant differences in grain hardness، broken rice percentage، elongation ratio، elongation after cooking، Amylose content and Gel consistency in different irrigation levels. Based on the results of the different irrigation methods، the best grain hardness amount (13. 1 Nioton) and reduced broken rice percentage (15 %) in Tarrom variety were obtained by the permanent flooding method، but for Shiroodi variety، the best grain hardness amount (17. 8 Nioton) and reduced broken rice percentage (19. 5 %) were gained by the permanent saturation method.