In order to identify the correlations and relationships between different traits in the bread wheat, 30 genotypes were investigated as sub-factors under the split plot experiment in the completely randomized design in greenhouse and the randomized complete block design in the field with three replications under the normal irrigation and post-anthesis water stress conditions. The results of the canonical correlation analysis showed that at both normal and moisture stress levels, there was a significant correlation between the pair of canonical variables obtained from the phenological traits and the yield components. Under the normal conditions in the greenhouse, to increase the spike density and length, the number of days to 50% flowering can be considered as a suitable selection criterion. According to the results of canonical correlation analysis, under the stressed conditions in greenhouse, to increase the spike length, the number of days to the heading, maturity and 50% of flowering were among the important and effective factors. Under the optimum irrigation conditions in the field, the number of days to maturity was considered as one of the factors influencing the seed weight per spike. The results of canonical correlation analysis under the field stress conditions showed that to increase the 1000-seed weight, the number of days to maturity can be considered an appropriate selection criterion.

This research was performed to determine the nutritional value of a halophyte species, Halostachys caspica in three different phonological stages including primary growth, flowering and seed ripening in three different sites i.e, Qom, Yazd and Urmia provinces Plant sampling was completely randomized and crude protein, ether extract, water percentage, acid detergent fiber, ash, dry matter digestibility and metabolism energy were measured by standard methods. Data analysis was done using SPSS software in a factorial design. According to the results, interaction effects of growth stages and different ecological sites showed a significant difference for most of the measured factors and they did not follow a regular trend. The results indicated that H. caspica had the highest forage quality in flowering (second stage) while with increase of plant age, crude fiber and ash increased in all the three studied sites. Growing in sever ecological conditions and having high forage quality, H. caspica may be considered for sustainable development plan in saline regions.

The aim of this research was to determine the role of optimum potassium fertilizer usage at phenological key stages of fruit growth in Miyagawa Satsuma mandarin in increasing the relative yield and fruit quality. To this end, potassium soil application (fertigation) and foliar application after fruit set, June drop, and cell expansion were evaluated in randomized complete block design with 5 treatments and 4 replications. Results showed that the highest yield, fruit average weight, and leaf potassium concentration was obtained from K fertigation after fruit set (middle of the first stage of fruit growth) and K foliar application after fruit set in cell expansion stage (second phase of fruit growth). All treatments significantly decreased fruits sunburn percent and increased fruit size and relative grade of fruit size, compared to the control. Potassium foliar application after fruit set and June drop had the maximum impact on relative increase of fruit diameter compared to the control and the percent of larger fruit increased relatively. Also, results showed that foliar application of potassium reduced the number of small fruits and increased medium and large fruits percentages. According to these results, it is recommended that potassium application as base fertilizer (before growth starts) be avoided and soil application begins after fruit set by fertigation; also, split foliar application of potassium nitrate should be done after fruit set and physiological fruit drop (June drop).

In order to compare heat indices at various phonological stages of com affected by different levels of densities and interference periods of sorghum, a factorial experiment was conducted on the basis of randomized complete block design with three replications in the growing season of 2002 at the Research Station of the Faculty of Agriculture, University of Tabriz, Iran. Studied factors consisted of different interference periods of sorghum (0, 14, 28, 42 days after com emergence), and sorghum densities of 4, 8, and 12 plant/m2. Com density was 7.8 plant/m2. Results showed that the best thermal indicator was the classical index to evaluate the effects of density levels and various interference periods of sorghum on com phonological stages in Tabriz area. This index had the highest correlation with the grain yield at all com phonological stages such as tasseling, silking and physiological maturity. Also, when winter crops were planted after com harvesting or ripening or seed filling duration, it can be recommend to use general thermal heat index. If the aim of artificial pollination is to produce hybrid genotypes. Three indices of growth degree day, crop heat unit and heat unit can be used due to their similar results. Finally, if the aim is to determine the silking, it would be better to use crop heat unit or heat unit.

In order to study the effects of water stress on growth parameter of wheat at different phonological stages, this experiment was conducted as split plot design with four replication. Main plot were include: jointing stage, anthesis and seed filling period. Sub plot were: Irrigation at field capacity, 75% field capacity,50% field capacity,25% field capacity. The results showed the highest and lowest dry matter accumulation obtained with applying water stress treatment at jointing stage and seed filling stage, respectively. With increasing water stress, the amount of dry matter decreased significantly. Also in greater water stress the value of LAI and NAR decreased.

Tall fescue is a high yielding perennial grass with wide adaptability to the adverse environmental conditions.This study was carried out to measure dry forage yield, chemical compositions and metabolizable energy (ME) of six tall fescue genotypes at two phonological stages. The selected genotypes were planted in a randomized complete block design with three replications at the research farm of Agricultural Biotechnology Research Institute of the Northwest Region in Tabriz in 2017. Based on the results of analysis of variance, the tested genotypes showed significant differences for all measured traits (P˂0.01). Dry forage yield was high in the genotypes Boroujen1 and Kamyaran2 with 325 and 270 g/plant respectively and low in the genotype Kamyaran3. The amount of crude protein, ME and acid detergent fibers (ADF) in the genotypes Boroujen1 and Borjen2 were better than the genotypes Fariman, Kamyaran1, Kamyaran2 and Kamyaran3 (P˂0.05), whereas the genotype Kamyaran3 had the lowest crude protein and ME and the highest ADF. Interaction of genotype ´ phonological stage was significant for all traits. At the heading stage, dry forage yield of the genotypes Boroujen1 and Kamyaran2 were the highest with 536 and 442 g/plant respectively and in the genotypes Fariman and Kamyaran3 were the lowest (P˂ 0.05). Based on the results of dry forage yield, the amount of crude protein, ADF and ME, the best genotypes were Boroujen1 and Kamyaran2.

To study the effect of drought stress at different phonological stages on yield and yield components of soybean cultivars, an experiment was conducted at the experimental farm of Darrehshahr Agricultural Station, Ilam Province (2009). The experiment was arranged as split plots based on Randomized Complete Block Design with three replications. The treatments that were drought stresses during the 4 leaves stage, flowering stage, podding stage and seed filling stage were located in the main plot and three cultivars (including M7, M9 and Hobit) were located in the sub plot. The results showed that in the %1 statistical probability level, the effect of drought stress and variety on plant height, fertile pod per plant, seeds per plant, seed yield, biological yield, hundred kernel weight, seeds per pod, harvest index and oil percentage were significant. Among soybean cultivars, M9 had the best performance regarding the seeds per pod, hundred kernel weight, seed yield and biological yield. The lowest seed yields were observed in the drought stress during the seed filling stage (2682 kg/ha) and flowering stage (2918 kg/ha), respectively. Both in stress and non stress conditions, the Hobit cultivar produced higher oil percentage than others. Finally, according to the results, M9 is recommended in Darrehshahr region and among all phonological stages, seed filling stage was more sensitive to drought stress occurrence.

Background and Objectives: Sesame is an oilseed plant that is resistant to drought but it is sensitive to water stress at seedling stage and during flowering to seed filling. Irrigation and drought stresses increase and decreases the amount of oil, respectively. Environmental stresses have reverse effects on the amount of oil and protein. In addition, high soil moisture causes root rot disease and low moisture causes phyllody disease. To increase the yield and oil, the enhancement of soil fertility, planting bred cultivar and adequate supply of moisture are necessary through irrigation. This study was conducted to evaluate the effect of irrigation intervals at different phonological stages on quantitative and qualitative characteristics and water productivity of sesame. Materials and Methods: This research was conducted in randomized complete block design with four replications at Behbahan Agricultural Research Station for two years (2013-2014). Treatments included I0 (irrigation interval based on farmer 's custom, twice weeks interval), I1, I2 and I3 irrigation after 90, 130 and 170 evaporation from class A pan, respectively, I4 (130 mm to flowering and afterward 90 mm), I5 (170 mm to flowering and afterward 90 mm) and I6 (170 mm to flowering and afterward 130 mm). During experiment: branches number and capsules number per plant, 1000-seed weight, first capsule height, plant height at harvesting time, seed oil percentage, seed yield, seed oil yield, water productivity of sesame seed and seed oil, root rot and phyllody diseases were recorded. Varince analysis were done by MSTATC statistical software and means were compared using Duncan, s Multiple Range Test. Results: The highest number of branches per plant (10. 31), number of capsules per plant (154. 50), 1000-seed weight (3. 78 g), seed yield (1381. 50 kg ha-1), oil amount (55. 11%), were recorded in I1 treatment, so that the highest seed oil yield (795. 55 kg ha-1) belongs to this treatment. The differences of oil yield among I1 treatment and I4 and I5 treatments were not significant. Maximum seed water productivity (0. 233 kgm-3) and seed oil water productivity (0. 125 kgm-3) were observed in I3 treatment. However, the difference among this treatment and I0, I5 and I6 treatments was not significant. The lowest infection severity to root rot disease (7. 22%) was recorded in I5 treatment. The highest infection severity to root rot disease (20. 63%) was observed in I1 treatment while the lowest infection severity to phyllody disease was recorded in I1, I2 and I6 treatments. Conclusion: The highest seed yield, 1000-seed weight and seed oil percentage were obtained in I1, I4 and I5 treatments. The differences of these characters among I1, I4 and I5 and other treatments were not significant (except I0 treatment). The highest seed oil yield were recorded for I1 and I5 treatments. The most seed water productivity and seed oil water productivity and the lowest water consumption belong to I5 treatment. Irrigation frequencies in I5 treatment were lower than I1 and I4 treatments. According to the results, I5 treatment has the lowest water consumption and the effect of this treatment on seed yield and gross income of seasame was similar to I1 treatment. Therefore, I5 treatment is recommended for proper irrigation of sesame in Behbahan region.

An important issue in some citrus varieties including Satsuma mandarin is alternate bearing. Therefore, to reduce alternate bearing in Satsuma mandarin trees, an experiment was conducted as randomized complete block design with 4 treatments and 4 replications. The experiment was done during 7 years with 32 Satsuma mandarin trees which were almost the same age and size. The experimental treatments of nitrogen use management included T1= Control (three splits, the first split late in March, the second late in April after fruit formation, and the third one month after the second split); T2= Summer application (15% before flowering, 30% after fruit formation, 20% at the time of physiological drop, and 35% after the beginning of fruit development); T3= Autumn application (15% before flowering, 30% after fruit formation, 30% at the time of physiological drop and 25% after fruit harvest); T4= Summer and autumn application (15% before flowering, 30% after fruit formation, 20% at the time of physiological drop, 20% after starting development, and 15% after fruit harvest). Results showed that fruit yield had the greatest difference in the first and second years of experiment and then the yield difference gradually decreased. The lowest cumulative yield ( ٣ ٧ ٩ kg/tree) was obtained from the control and the highest cumulative yield (446 kg/tree) was obtained from summer and autumn N treatment. Results showed that the control had the highest alternate bearing index (0. 40) and autumn N application treatment had the lowest treatment index (0. 18). Also, year had a significant effect on fruit average weight as the highest fruit average weight was obtained in the fifth year. In all N application treatments, fruit average weight was significantly more (at 5% level) than the control. Based on the results of this study, to minimize alternate bearing, the time and amount of nitrogen fertilizers are recommended in the following four stages: 15% at the beginning of flowering, 30% between fruit set and the beginning of June drop; 30% at the beginning of June drop to early phase of the second growth of fruits; and 25% after fruit harvest.

Rain fed wheat is one of the major agricultural crops in Kurdistan province that includes most of the cultivated area. Agricultural production is affected by risks, resulted from weather and international markets. Although these risks could never completely been removed, we can minimize their effects by realizing the affecting parameters involved in plant growth and crop yield. In this study the impacts of effective agroclimatological indices and climatic elements have been identified for each phenophase of rain fed wheat yield in Kurdistan province. For this purpose, rain fed wheat yield data for Kurdistan province, and its counties were obtained from The Ministry of Jahde Agriculture for the period 1991-2006. Moreover, Necessary weather parameters of all the weather stations in Kurdistan province for the period 1991-2006 (1993-2006 for Marivan station) were obtained from Iranian National Meteorological Organization. Correlation and nearest neighboring methods were used for retrieval of the missing data. Then, linear and nonlinear correlations between rain fed wheat yield and 6 agroclimatological indices (TD, GDD, HTU, PTU, VPD, PET) and 11 climatic elements (Tmax, Tmin, R, Rday, RH, Tabsmin, Tabsmax, FFmean, FFabsmax, TS, Tmean) in 6 pheneological phase of rain fed wheat growth from sowing to harvest, were extracted. The results of this study show that the effective variables in each phenophase of rain fed wheat yield growth are; temperature in the first phenophase (Early Seedling stage, from October 7 to November 6); precipitation in the second phenophase (the First Stage of Active Vegetative before Dormancy stage, from November 7 to December 11); temperature variations in the third phenophase (Dormancy Stage, from December 12 to March 15); relative humidity and the absolute amount of minimum temperature in the fifth phenophase (Reproductive Stage, from May 11 to June 9); and relative humidity in the sixth phenophase (Maturity Stage, from June 10 to July 10). In the fourth phenophase (the Second Stage of Active Vegetative after dormancy stage, from March 16 to May 10) none of the extracted variables and indices have a significant relation with rain fed wheat yield. This shows that wheat plant obtains necessary climatic elements from previous phenophases and continues its growth in this stage.