This experiment was carried out at Neka, Mazandaran, Iran in 2011. This experiment was done as split plot in randomized complete blocks design based four replications. Planting systems were chosen as main plots (Conventional, Improved and SRI or System of Rice Intensification) and genotypes as sub plots (Tall cultivars: Sang Tarom and Hashemi Tarom; Semi dwarf cultivars: Neda and Shiroodi). The results showed that maximum panicle length, plant height and grain yield was obtained by improved system. Maximum 4th inter-nodes length, 3rd and 4th inter-node bending moment, 3rd and 4th inter-nodes lodging index and straw yield was presented by conventional system, but breaking resistance by SRI had maximum tolerance. Hashemi Tarom cultivar had maximum panicle length, plant height, 3rd and 4th inter-nodes length and 3rd inter-node bending moment. Maximum 4th inter-node length, 3rd and 4th inter-nodes lodging index and straw yield was determined for Sang Tarom and Hashemi Tarom cultivars. But highest grain yield was noted for Neda and Shiroodi cultivars. Maximum plant height and 4th internodes lodging index was found by interaction conventional system × Hashemi Tarom cultivar. So according to the results improved system was the best one because of decrease in lodging and increase in grain yield.
