This study was conducted to evaluate the gene effects, heritability, heterosis and identification of appropriate breeding methods for improving rice viscosity parameters, during 2014-2016 at Rice Research Institute of Iran. The progeny obtained from the North Carolina III mating design with their parents were planted in a randomized complete block design with three replications. Analysis of variance for viscosity parameters revealed that the effect of females, male effect and interaction between males and females effect were significant for all parameters with the exception for peak viscosity. Evaluating of genetic parameters indicated that viscosity characters are affected by additive and non-additive effects of gene action. The share of non-additive effects in genetic control of peak viscosity had beyond additive gene action, while, the contribution of additive effects was greater for the breakdown viscosity, final viscosity and setback viscosity. High estimates of broad sense heritability revealed that the expression of viscosity parameters is more influenced by genetic effects. With regard to non-additive gene actions and low narrow sense heritability estimation in peak viscosity, using hybrid based programs would be promising to improve this trait. For other viscosity parameters, narrow sense heritability estimates were high. Therefore, the use of selection based programs to improve these traits is encouraging. Assessing of relative heterosis through mid-parents showed that heterosis ranged from -3.73 to 1.93%, 5.51 to 21.33%, -4.57 to 1.26% and -26.04 to 9.36%, for the peak viscosity, breakdown viscosity, final viscosity and setback viscosity, respectively.

Sweet flag (Acorus calamus) is a perennial, semi-aquatic and aromatic plant of the family Acoraceae that, in addition to its multiple medicinal properties, is used in health, food and agricultural industries (as pest control). This research was conducted to comparasion study of genetic diversity of natural and regenerated plants from tissue culture of Arzefon, Pelesk and Alandan populations of Sweet flag by using ISSR molecular markers. Out of 15 screened primers, 9 primers produced the most polymorphic bands. Totally, these primers generated 83 bands, of which 52 bands (62.65%) were polymorphic. The percentage of polymorphic locus for natural and regenerated plants was 43.37% and 55.42%, respectively, and Nei’s genetic diversity (H) was calculated to be 0.239 for the two studied groups. The Shannon’s index (I) for natural and regenerated plants was estimated to be 0.251 ± 0.033 and 0.299 ± 0.031, respectively. Among the natural and regenerated groups, the highest genetic similarity was observed between the samples of Alandan population (0.63), and the lowest value was observed between the samples of Pelesk population (0.44). Analysis of molecular variance (AMOVA) showed that 94 % of genetic variation attributed to whithin groups and 6 % to between groups. Based on the results, the genetic diversity of the regenerated plants was higher than the natural plants. According to the results of the present research, the lowest rate of genetic divergence was observed between natural and regenerated plants of Alandan populatiuon, so the plants of this population could be suitable for domestication and cultivation in Iran.