Effect of Seed Priming on Lodging Indices of Rice (Oryza sativa L.) Cultivars in Direct Seeding Method

In order to evaluate the effect of seed priming on lodging-related characteristics in direct seeding method, a study was conducted in a factorial randomized complete block design with four replicates in the research field of Rice Research Institute of Iran (Rasht) for two years. The first factor consisted of two rice cultivars (Khazar and Hashemi) and the second one consisted of ten levels of seed conditions encompassing, eight priming treatments including hydropriming, ascorbic acid, salicylic acid, CaCl2, cold, cold heat, seed coating, and non-primed dry seed, all sown with seed tap technology along with linear direct seeding of germinated seeds and transplanting (25-days-old seedlings). Agronomic and morphological characteristics and resistance to lodging indices were measured. The results showed that there were significant differences between two cultivars and ten levels of seed conditions in morphological traits and lodging resistance indices. Mean comparisons and correlation analyses showed that grain yield (5142 kgha-1), resistance to fracture in third and fourth internodes (549 and 704 Newton, respectively) in Khazar were higher than those of Hashemi. There was a significant difference between planting methods (direct-seeded and transplanting) in terms of lodging resistance. Maximum indicators in the third and fourth internode bending momentum (1060 and 1708 gcm-1) were observed in the transplanting method. Hydropriming treatment had significant effect on fourth internode thickness in cultivar Khazar. Priming treatments appeared to leave significant effect on resistance to lodging in different planting methods in a cultivar-specific manner.