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.

In order to determine yield stability of 23 bread wheat genotypes and two commercial cultivars as check, an experiment was conducted based on a randomized complete block design with three replications in the experimental field of faculty of Agriculture, Razi University Kermanshah (Iran), during three cropping seasons (2015-2018). The results of combined ANOVA showed that the effect of environment, genotype and genotype × environment interactions on grain yield were significant (P<0.01). Stability was evaluated using environmental variance statistics, coefficient of variation, Wrick´s ecovalence, Shukla’s stability variance, Regression slope, deviation from regression slope, Plaisted and Peterson method and AMMI model. Variance analysis of additive main effects and multiplicative (AMMI) showed that three IPCAs were significant at 1% probability level. The first three principal components justified a round 85.7% of the sum of square of the interaction. Also, AMMI stability value (ASV) was used for simultaneously using information obtained from two significant components of AMMI. According to ASV index, genotypes Pishgam, Wc-4958 and Pishtaaz had the lowest ASV value and were known as the most stable genotypes. Genotypes Wc-4987, Wc-47615, Wc-47399 and Wc-47638 had the highest ASV value and distance from the center of Bi-plot. Therefore, Pishtaaz is one of the most stable genotypes due to having the first rank in terms of studied parameters as well as proper bakery properties and desirable drought resistance. In general, regarding to the climate change in the country, especially in the rainfed conditions and based on the above statistics and the biplots derived from AMMI analysis, the Wc-4958 line, with pishtaaz and Pishgam cultivars as stable and adaptable genotypes, are suggested to rainfed conditions on the studied area.