فصلنامه تحقیقات غلات
سال دوم شماره 4 (زمستان 1391)

Performance of a given genotype might vary from one location to another one, which is called genotype×environment (G×E) interaction. The study of G×E interaction and identification of stable and high performance varieties is important for breeders. In the present study, stability and adaptability of 20 barley genotypes was studied in uniformity trials using randomized complete block design with three replications at 8 cold regions during two consecutive cropping seasons (2005 and 2006). Results of AMMI analysis showed that the genotype and environment main effects, G×E interaction and four principal components of interaction effect were significant at 1% probability level. First and second principal components were used to draw biplot curve. Cluster analysis grouped the studied genotypes into three groupes. Overall, the promising line No. 17(MAKOUEE//ZARJOW/80-5151) was recognized as the best genotype examined in terms of being a high yielding and stable genotype. Therefore, this genotype was recommended for on-farm trials and release. It was concluded that although breeding stable and adaptable cultivars for such a vast climatic zone is difficult, it is possible to seek for the best fitted genotypes to both narrow and wide adaptations using the information extracted from the stability analyses performed.

To estimate the genetic characteristics related to baking quality traits such as thousand kernel weight, grain Protein content, Zeleny sedimentation volume, bread volume, kernel hardness, water absorption, falling number, wet gluten and SDS sedimentation volume in genotype of parents and F2 crosses, using diallel cross of six commercial cultivars such as Atrak, Arvand, Zarin, Karaj -3, Mv-17 and Navied were used. The trials (Two years) in the years, 2010 and 2011 carried out in a randomized complete block design with three replications at the research station of Mahidasht Kermanshah. The data resulting by GGE Biplot and Hayman method analyzed. The results of combined analysis of variance indicated differences between genotypes for all traits was highly significant. Two geneticratio G C A S C A s 2 s 2 and G C A S C A G C A (2s 2 + s 2) 2s 2 showed that greater share of the gene additive effects was at the control characters. GGE Biplot analysis showed that parents of Atrak, Zarin and Karaj-3 with maximum GCA in the important quality characters are advisable. Combinations of the Atrak × Zarin, Zarin × Karaj- 3, and Atrak × Karaj -3 with maximum SCA can be used to enhance the qualitative and quantitative traits. Test of epistatic using regression coefficient and analysis of variance Wr-Vr showed that additive- dominant models for Zeleny sedimentation volume, kernelhardness, falling number and wet gluten percentage of adequacy has more, but in other traits epistatic effects exist. Also results of analysis based on Hayman method showed the prevalence of additive effect over the non-additive effect for all traits. The highest and lowest heritability of traits belonged to times of grain protein content and falling number, which was 75% and 25% respectively. By transfer of additive genes and their cumulative effects of the characteristics in next generation, can be increased the characteristics by selection in early generations of baking quality traits in bread wheat breeding program can be used.

To select stable and high grain yield wheat varieties as well as to determine suitable sowing date for cold agro-climatic zone in Iran, eight wheat varieties were studied using randomized complete block design with four replications in six locations (Sanandaj, Gorveh, Marivan, Divandarreh, Saggez and Baneh) during three growing seasons (2007-2010). Since interaction of cultivar × year × location was significant, stability analysis was performed using different methods. Results of stability analysis with shukla’s stability variance method showed that the Zarrin and Sabalan varieties were more stable than other varieties. Also, lowest environmental variance was belonged to Azar 2. The results of ranking method showed that cultivars Sabalan, Bezostiya, Alvand, Alamout and Omid had the lowest i R and cultivars Alvand, Sabalan, Navid, Zarrin and Omid had also the lowest SDR among the experimental cultivars. Results of stability analysis with yield - stability statistic (YSi) method indicated that the varieties Alvand and Alamout were the most stable varieties, respectively. Results of this research showed that the Alvand and Sabalan varieties had the highest yield stability than the other varieties and can be recommended for studied locations.

To study genetic variation and terminal drought stress on kernel yield and some physiological traits in bread wheat, an experiment was conducted using 80 irrigated bread wheat genotypes in a randomized complete block design (RCBD) with three replications under normal and terminal drought stress conditions in research farm of the Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, during 2011-2012 cropping season. The result of combined analysis of variance indicated high significant differences among genotypes for all studied traits except “chlorophyll b” and total chlorophyll. Moreover, effect of the environment on relative water content, kernel yield, kernel filling duration and kernel weight was highly significant. Terminal drought stress reduced “chlorophyll a”, SPAD and relative water contentas much as 3.54%, 2% and 10%, respectively but it increased “chlorophyll b” and total chlorophyll by 6.16 and 2.68%, respectively. In addition, drought stress caused reduction in kernel yield (23.48%), kernel filling duration (19.14%) and kernel weight (18%) but it increased kernel filling rate by 2.20%. There were high negative significant correlation between “chlorophyll a” and “chlorophyll b” and between kernel filling rate and kernel filling duration, whereas, correlation between “chlorophyll b” and total chlorophyll and between kernel filling rate and kernel weight were highly significant and positive. Correlation coefficients exhibited no significant associations between kernel yield and other traits in both normal and drought stress conditions.

To investigate the effect of post emergence sulfonyl urea herbicides on weed population of maize, an experiment was conducted in a randomized block design with 8 treatments and 3 replications in Arak region, Iran, in 2012. The treatments were including rimsolfuron + once hand weeding, nicosolfuron + once hand weeding, nicosolfuron + rimsolfuron + once hand weeding, twice hand weeding and weedy check. The most important weeds in this experiment were common lambsquarters (Chenopodium album), field bindweed (Convolvulus arvensis) and bermudagrass (Cynodon ductylon). Results showed that average weed dry matter for the treatment of weedy check was 40.18 g.m-2 and nicosolfuron + rimsolfuron + once hand weeding was the most effective treatment, because it had the lowest weed dry matter with 88.96% reduction in comparison with weedy check. The treatment of 40 g.ha-1 rimsolfuron had the lowest affectivity by controlling only 58.57% of the weeds. Even though none of the treated herbicide showed crop injury, but nicosolfuron + rimsolfuron +once hand weeding with 4514 kg.ha-1 and the weedy check with 1209.25 kg.ha-1 grain yields produced the highest and the lowest amount of yields, respectively. Thereby, yield reduction of weeds in corn cost 27% in comparison with weed free treatments.

Blast disease caused by Pyricularia oryzae is the principal disease of local rice cultivars innorthern Iran. Because of this, its chemical control is being in possession of special priority.Application of various fungicides and fungicides mixture is an important strategy on the chemical management of this disease. In this study efficacy of Vista®, as a fungicide mixture (tricyclazole + thiophanate methyl WP 72.5%) was evaluated in controlling of rice leaf, panicle, neck and node blast disease with dose rates of 400, 500 and 600 g/ha, in comparison with recommended fungicides, tricyclazole (WP 75%), carpropamid (SC300 50%) and edifenphos (EC 50%) with dose rates of 500g, 400 ml and 1000 ml per hectare respectively, in randomized complete block design under field condition in 2010 and 2011. In Rasht county, the results revealed that the effects of fungicides Vista® with all three dosages, carpropamid and tricycalazole were more significant to control of leaf blast on Hashemi cultivar in comparison with control treatment, at both time ofevaluation. All fungicides had significant effect to reduce panicle and node blast (exceptedifenphos) in first year and neck blast (except edifenphos) in second year. In second year node blast was seriously developed and application of tested fungicides was not significantly effective to reduce of node blast in comparison with control treatment. In Amol county, edifenphos was the least effective of all the fungicides in controlling of leaf blast disease as similarly found in Rasht county.