gh. a. akbari

To evaluate the plant adaptation and effects of irrigation cycles and NPK elements on growth and yield parameters of Zingiber officinale R., a split-plot experiment was conducted as a randomized complete block design with nine treatments and three replications in two regions including Pakdasht (Tehran province) and Lahijan (Gilan province) in 2021. The experimental factors included irrigation cycle at three levels (4 (V1), 6 (V2), and 8 (V3) days) as the main factor and NPK elements at three levels (N300P100K200 (F1), N350P150K250 (F2), and N250P50K150 (F3) (kg.ha-1)) as the sub-factor. The results showed that the irrigation×NPK effects was significant on plant height, number of leaves per plant, leaf area, number of branches per plant, leaf area index, fresh and rhizome dry weight, and rhizome yield at the 1% probability level and on stem diameter at the 5% probability level in Pakdasht region. The V1F2 treatment was the best one in this region. In Lahijan region, the irrigation×NPK effects was significant on number of leaves per plant and rhizome yield at the 1% probability level and on plant height and stem diameter at the 5% probability level. The best result in Lahijan was obtained in the V1F2 treatment. Also, in terms of leaf area, number of branches per plant, and leaf area index, V1 and F2 was the best treatments in Lahijan. Fresh and rhizome dry weight had the best results in the V2 and F2 treatments. Overall, the studied traits in Lahijan climate were superior to Pakdasht climate and every 4 days irrigation for Pakdasht and every 6 days for Lahijan had the best results.

In order to evaluate the agronomic characteristics and some physiological traits of canola varieties under drought conditions, separate experiments were carried out at the Research Field of Yazd Agricultural and Natural Resources Research Center in 2011-2012. Each experiment was conducted in a randomized complete block design with three replications. In the first experiment (control) that was conducted under optimal irrigation, plants were irrigated based on 80 mm evaporation from pan class A at all stages of plant growth, in the second experiment, drought stress was applied at stem elongation up to maturity stage, in the third experiment, drought stress was performed at flowering up to maturity stage and in the fourth experiment, drought stress was performed at silique formation up to the end of maturity stage using three canola varieties including GKH2005, Opera and Okapi. The results of combined analysis showed that withholding irrigation started at stem elongation, flowering stage and silique formation reduced the silique number in the main stem by 44, 34 and 9 %, silique number per branches by 60, 34 and 17 %, seed number in silique per main stem by 62, 35 and 5 %, seed number in silique per branches by 73, 46 and 11 %, 1000- seed weight by 19, 28 and 26 % and seed yield by 62, 51 and 27 %, compared with the control conditions, respectively. The greatest grain yield was obtained from the control experiment as 3110 kg/ha and followed by withholding irrigation from silique formation, flowering stage and stem elongation with corresponding values of 2510, 1773 and 1450 kg/ha, respectively. Drought stress reduced the stomatal conductivity, relative water content (RWC) and cell membrane stability, whereas SPAD value was higher under drought conditions as compared with the control experiment. Under drought stress among studied cultivars, GKH had the maximum silique number, seed number in silique and seed yield due to the least electrolyte leakage percentage, higher stomatal conductivity and relative water content (RWC). The overall results of the experiments showed that withholding irrigation from silique formation owing to the reduction in irrigation frequency and efficient use of it in summer crops irrigation accompanied with the employment of drought tolerant varieties can be effective in increasing productivity and canola cultivation areas in arid and semi-arid regions.

Medical pumpkin is a medicinal plant that has a special place in the pharmaceutical industry, and evaluation of quantitative and qualitative yield is a under different agronomic treatments is necessary. Investigating of quality/quantities yield of oil and morphological traits of Cucurbita pepo. affected of planting date and row arrangement. This study was done as split plot on complete randomized blocks design with 3 replications at Research field of Aburaihan College, University of Tehran in 2010 and 2011 years. Treatments were included 3 main plots of planting dates (20 Apr, 21 May and 21 June) and 3 sub-plots of row arrangement (1, 1.5 and 2 meter between two rows). In this study evaluated 1000 seeds weight, seeds number in fruit, seeds weight per fruit, seed yield, seed produce index, oil percentage and oil yield. The year had not significant effect on any traits expect of oil percentage and seeds number in fruit. The interaction of planting date and row arrangement were significant in all quality and quantity traits. Maximum of seed yield, seed oil percent and oil yield were obtained in 1 meter row spacing21 may treatment and 1.5 meter21 June treatment. Maximum of unsaturated fatty acids percent and minimum of saturated fatty acids percent were obtained in planting date of June with 1.5 and 2 meter row spacing. According to significant effect of row arrangement and planting date on seed and oil yield of medical pumpkin, quality and quantity growth followed economic yield of this plant could be improved by using appropriate agronomic management.

A field study was conducted at Abourehan research farm of Tehran University in 2009 to find out the effects of slow releasing nitrogen from pellet fertilizer of nitrogen and manure on grain yield and some Physiological Characteristics of corn (Single Cross 704). The factorial design of the study comprised of randomized complete block with three replications. Factors this experiment involved: first factor was Two levels of application method fertilizer include (pellet and mixed with soil) and second factor was four levels of nitrogen fertilizer pulse manure include (46+600, 92+600, 138+600 and 184+600 kg ha-1) In this research, a Screw Extruder setup was designed and manufactured. N fertilizer Increasing from 46 to 184 kg/ha had significant effect on all yield and yield components traits except number of rows per ear. Maximum grain yield was obtained with pellet and 184 N kg/ha treatment. Also LAI, CGR and NAR curve was maximum with applying pellet and 184 N kg/ha treatment. Results showed pellet method through decreasing of leaching and slow releasing of N, cause low consumption of N to 50%.

In order to Study of some effective phenologic and physiologic characteristics on 18 sunflower hybrids yield under optimum conditions, an experiment was conducted as randomized complete block design with three replications at the research field of Seed and Plant Improvement Institute-Karaj in 2006-2007. The result indicated that the hybrids showed significant difference in phonologic characteristics, number of photosynthesis active leaves and leaf area index in seed filling stage, photosynthesis active radiation and red to far red ratio in bottom canopy, radiation interception, 1000 seed weight, seed yield and seed oil content, whereas in seed number per plant and harvest index not significant difference. In this experiment, intermediate and late maturity hybrids had the great leaf area index and with the better photosynthesis active radiation absorption. Also it had the maximum radiation interception and produced the highest seed yield in comparison with early maturity hybrids. Correlation coefficients analysis demonstrated that seed yield had positive and significant correlation with filling stage duration, reproductive stage duration, growth stage duration, leaf area index, 1000 seed weight, seed oil content and harvest index, whereas red to far red ratio in bottom canopy has the negative and significant correlation with seed yield. Mehr hybrid with long flowering duration (6 days) and moderate growth period (98 days), could be used for optimum conditions. Therefore it had the high leaf area index (3.3) and radiation interception (0.98) and produced the highest seed number per plant (980), seed yield (3861 kg.ha-1) and seed oil content (48.3).

In order to study of the radiation interception and red to far red light ratio variations in sunflower hybrids under drought stress, Nine sunflower hybrids in three separate experiments were compared as randomized complete block designs with three replications at the Research Station of Seed and Plant Improvement Institute in Karaj in 2006. First experiment (control) was irrigated based on 60 millimeter evaporation from evaporation pan. The second and third experiments were irrigated at 120 and 180 millimeter evaporation from class A evaporation pan, respectively (medium and sever drought stresses, respectively). Average of solar radiation intensity and red to far red light ratio in bottom canopy, Solar radiation interception, number of active leaves, total dry weight per plant at seed filling stage and seed yield showed significant difference among irrigation treatments. The intensity of drought stress increased the solar at the bottom of canopy and red to far red ratio by 35 and 45 percentages, whereas caused to decrease the radiation interception of control treatment as 0.95 to 0.88 in sever drought stress. Results indicated that Allstar hybrid with appropriate leaf area index (LAI) and number ofactive leaves and maximum radiation interception produced the highest dry weightand seed yield, in drought stress conditions.Keywords: Sunflower; Drought stress; Seed filling stage; Solar radiation interception

In order to investigate the limited irrigation impact on physical characteristics of seed in nine sunflower hybrids, three 3-replicate field experiments RCBC were conducted under three irrigation regimes (irrigation after 60, 120 and 180 mm cumulative evaporation from class A evaporation pan, respectively) at the research field of Seed and Plant Improvement Institute in Karaj, Iran. The results showed that the Maximum length, width and seed diameter were obtained from irrigation after 60 mm cumulative evaporation from pan, and irrigations after 120 and 180 mm evaporation caused to decrease the length by 11% and 16%, width by 21% and 26% and seed diameter by 22% and 28%, respectively. There fore the seed diameter in comparison with width and seed length was most susceptible to limited irrigations levels. The Maximum length was seen in hybrid of A74×R95, and the maximum width, and seed diameter were observed in hybrids of Allstar. Also, A74×R95 under irrigations after 60 and 120 mm evaporation and Azargol under irrigation after 180 mm evaporation had the highest seed weight.