نشریه علوم به زراعی گیاهی
سال یازدهم شماره 1 (بهار و تابستان 1400)

In order to determine the most appropriate planting distance and cultivar and also to find the most effective traits in watermelon yield at different planting densities, this study was conducted as split plots in three replications for two cropping years 2016-2017 in Jiroft. Plant spacing (40, 50, 60 and 70 cm) and four watermelon cultivars (Patangra, Favorite, CrimsonPS and CrimsonG-53 were divided into main and sub-plots, respectively. There was a significant effect on the studied traits except the thickness of the fruit skin, so that the number of fruits and yield decreased significantly with increasing plant distance on the planting line; The highest values of these traits were 0.99 and 23.82 tons.hectare-1 at a distance of 40 cm, respectively. But the quality and appearance of the fruit at a distance of 70 cm had its highest value. Increasing the culture distance from 40 to 70 cm increased the amount of soluble solids by 12%. The studied cultivars were significantly different in all traits except Brix. CrimsonPS and CrimsonG cultivars had the highest yields during the two years of testing at 22.50 and 20.76 tons per hectare, respectively. CrimsonPS cultivar was relatively superior to other cultivars in terms of most of the studied traits, and this ultimately led to the highest yield per unit area. Path analysis showed that in different cultivation densities, fruit number and single fruit weight had the greatest effect on fruit yield; These two traits were selected as the most important traits in determining fruit yield.

The use of medicinal plants in contaminated soils with heavy metals is of significance for the bioremediation of the environment and for plant growth. The effects of cadmium (Cd) and lead (Pb) on the growth of roots and aerial parts, and the number of flowers in Matricaria chamomilla L. were investigated in greenhouse and field conditions using 10-kg pots containing polluted soil with Cd (0, 10, and 40 mgkg-1) and Pb (0, 60 and 180 mgkg-1) in 2018-2019 in Isfahan (Khorasgan) Islamic Azad University. The effects of the experimental treatments including metal concentration was significant at 5% level, growth stage and location, plant tissue and their interactions significantly affected plant growth (dry weight) was significant at 1% level. Increasing Cd and Pb concentrations decreased number of flowers in the field and increased it in the greenhouse. Plant growth significantly decreased by increasing heavy metal concertation was significant at 5% level as at the first, second and third contamination levels, it was equal to 480.39, 416.00, and 399.33 g, respectively. The highest plant growth was resulted at flowering (500.78) and tillering (511.67 g), significantly at 5% level higher than that of stemming (283.28 g). Compared with Pb (407.44 g), increasing Cd concentration, resulted in significantly at 5% level higher reduction (333.11 g) of plant growth. It is possible to grow Matricaria chamomilla L. in heavy metal polluted soils for the bioremediation of the environment.

To investigate the effect of planting date on yield and some agronomic traits in local and high-yielding rice cultivars in direct cultivation by dry-bed seeding system was conducted in the form of a split-plot in a randomized complete block design with three replications. The main plot of planting date in three levels (June 15, June 25, and July 5) and four rice cultivars including two local cultivarsChampa and Red anbori and cultivars High-yielding and improved Danial and Shafagh was grown as a subplot at each planting date. Then, each plot was divided into two parts. The upper part of plot was not weeding and was considered as a control and the lower part of the plot was removed by hand weeding. Based on the results, the effect of planting date and cultivar on biological yield, grain yield, and the number of spikes per square meter under weed control conditions was significant at the level of one percent. In this experiment, the highest yield was observed on the date of the first planting in the high-yielding cultivar Shafagh and at the rate of 5253 kg/ha. The results showed that grain yield loss due to weed presence was different depending on planting date, so that the highest and lowest production loss with the average of 1815 and 1090 kg/ha was related to the first and third planting date, respectively. Among rice cultivars, a decrease in grain yield of 40.85 and 32.95 percent was observed in high-yielding cultivars and local cultivars, respectively.

This study aims to identify relationships as well as the positive and negative influence of the related traits to the sugar of organs and different periods of growth, ion, biochemistry, enzyme and hormone as the independent variable with the grain yield as the dependent variable. Twelve genotypes were carried out in the random complete blocks’ design with three replications that were consistent with the climate conditions of Khuzestan. They can impact significantly on the grain yield changes in the sugar of the vegetative, reproductive organs at the stage of physiological maturity of the flag leaf and root, in the pollination stage, in the nitrogen ions, in the biochemical traits of the Malondialdehyde, protein, starch and proline attributes and between the abscisic acid enzyme and hormone, Catalase and Guaiacol. The sugar in the flag leaf had the highest percentage of significant change in the level of 1% with the yield grain at the physiological maturity stage, nitrogen, Malondialdehyde (MDA) and abscisic acid, with negative, positive, negative and negative relation, respectively. The obtained results can be the major and important target for genetic modification of the rice varieties to increase the grain yield of the plant as an economic and strategic product.

Fungal symbiosis can be beneficial for plant growth and nutrition by increasing the absorption of nutrients and using biochar as a soil conditioner that improves the physical, chemical and biological conditions of the soil. Different amounts of biochar and mycorrhiza on yield and some morphophysiological traits in wheat were performed during the cropping years of 2016-2017 and 2017-17 in Zohreh city located in southwestern Iran. The experiment was performed as a factorial experiment in a randomized complete block design (CRBD) with four replications. mycorrhizal fungus at two levels including non-use (control) and use of Glomus intradiaces and biochar values from plant biomass and agricultural wastes as soil modifiers at three levels of non-use (control) and application 4 and 8 Tons per hectare. The results of analysis of variance showed that mycorrhiza and biochar at 1% level had no significant effect on biological yield, grain yield, harvest index and some components of grain yield such as number of spikes per square meter and grain per square meter. The interaction of different amounts of biochar and mycorrhiza on 1000-seed weight, number of spikelets per spike, numbers of seeds per spikelet and grain protein percentage were significant at the level of 1% probability. The results showed that the amount of grain protein (8%), number of spikelets per spike (11%) and 1000-seed weight (16%) showed a significant increase compared to control plants. the application of four tons per hectare of biochar in plants inoculated with mycorrhizal fungi had the best conditions and yield (23%).

Prediction of weed emergence timing would help reduce herbicide use through the optimization of the timing of weed control. In order to predict the emergence of wild buckwheat (Polygonum convolyulus L.), alkafaun (Fumaria vaillantii Lois) and Field bindweed (Convolvulus arvensis L.) by using the temperature model, an experiment was conducted at wheat field research of university of Tehran, Karaj during 2012-13. Based on the results, 50 percent of cumulative emergence of wild buckwheat were obtained in 75.21, 71.48 and 75.21 growing degree day at inner margin, center and outer margin of wheat field, respectively. The presence of wheat was not impressed the emergence of wild buckwheat. It was for that this weed was not required light for germination. Alkafaun emergence was happened at higher growing degree day at inner margin of field. Of course alkafaun had lower emergence per received GDD at outer margin in comparison with other parts of the field. Although emergence had lower slope per growing degree day at this part, but it was achieved to 50 percent cumulative emergence with lower received GDD. It was this time that 50 percent cumulative emergence of alkafaun achieved with 49.11 and 45.90 GDD at center and outer margin of field, respectively. Field bindweed was achieved to 50 percent of cumulative emergence with 158.98 and 150.60 growing degree day at inner margin and center of field. but there was no direct correlation between the number of weeds in the wild buckwheat seed bank and the number of seedlings were emerged.

The aim of this study was to determine the role of different irrigation regimes on flag leaf and other leaves , stem length, stem weight, average leaf length and width of aerobic rice genotypes was carried out during 2014 and 2015 in Shavoor Agricultural Research Station in northern of Khuzestan. Four irrigation regimes (1, 3, 5 and 7 days) in main plots and twelve rice genotypes in subplots with three replications. The results of combined analysis showed that there was a significant difference between genotypes, irrigation regimes and their interactions in all traits. One-day and three-day irrigation regimes had the highest and the seven-day irrigation regimen the lowest in terms of less time in nutrient accumulation in all traits. Grain yield, while having the highest positive and significant correlation (0.486 **) with flag leaf weight in terms of providing the most photosynthetic material for the main reservoir in the All genotypes tended to produce the most grain yield in the second irrigation regime (the three-day irrigation interval); genotype IR 81025-B-327-3, with 6555.10 kg ha-1 of grain yield, out-performed the remaining genotypes in this level of irrigation regime. Examination of the growth index showed that all genotypes reached their maximum growth by reducing the irrigation cycle in a shorter period of time, while more resistant genotypes maintained their growth process in the conditions of better irrigation cycle reduction, which can be due to breeding and Corrected figures used.

In order to determine the most suitable cultivars and barley lines in different planting dates, an experiment was conducted during 2019-2020 in Ghizanieh region of Ahvaz. The main factor includes three planting dates (1 November, 16 November and 1 December) and the sub-factor also includes six cultivars and lines of barley (Auxin, Nowruz, Nimroz, WB-95-3, WB-95-9 and WB-95-19) was done using split plots in a randomized complete blocks design with three replications. The measured traits were stem length, spike length, grain length, number of hollow seeds, number of seeds per spike, 1000-seed weight, number of spikes per square meter, grain yield, biological yield, harvest index, grain nitrogen percentage, grain protein percentage and plant growth indices. Results showed that the effect of sowing date on grain yield, number of seeds per spike and number of hollow seeds was significant at 5 درصد probability level. Planting date of 1 November reduced seed yield and increased number of hollow seeds and the third planting date also reduced number of seeds per spike and grain yield. Nowruz cultivar had more spikes per square meter in early planting date than late planting date. At the date of early sowing of barley, the highest number of hollow seeds was produced per spike. In late planting, plant height decreased and as a result, the biological yield also decreased. Planting date of 16 Nov. had the highest number of seeds per spike.  The highest yield obtained in Auxin cultivar with an average of 7710 kg.ha-1 on the second  planting date and line WB-95-19 at the same planting date with an average of 7226 kg.ha-1. 16 Nov. planting date, which had the highest seed yield, had the highest LAI and NAR. Seed nitrogen had the highest level in early sowing date in WB-95-3 line and decreased in late sowing dates. In general, the results of this experiment showed that early sowing of barley, reduced grain yield and sowing of Auxin cultivar on November 16 in Ghizaniyeh region had the best economic yield.