جستجوی مقالات مرتبط با کلیدواژه "عملکرد دانه و اجزای آن" در نشریات گروه "زراعت"

Since there is no information available regarding crop management, including proper planting arrangement and optimal planting density, of the imported shattering tolerant sesame genotypes, field experiments were carried out in research fields of Seed and Plant Improvement Institute, Karaj, and Khorasan Razavi Agricultural and Natural Resources Research Center, Mashhad, Iran, in 2019 and 2020. The effect of experimental factors including; 30, 45 and 60 cm inter row spacing, and 5, 8, 11 and 14 cm intra row spacing were evaluated as split blocks (strips) arrangements in randomized complete block design with three replications. The results showed that there was reduction in number of sub-branches in both locations due to reduction in inter row spacing and intra row spacing. On the other hand, the reduction in plant density m-2 increased the number of capsules plant-1 and seed number capsule-1. The highest seed yield (1342 and 604 kg ha-1 in Karaj and Mashhad, respectively) obtained from the 45 × 8 and 45 × 11 planting arrangement in Karaj and Mashhad, respectively. Generally, the results indicated that there is an optimal planting arrangement and planting density for each location. Therefore, due to increased competition between plants in high plant density and lack of proper utilization of resources in low plant density, it would not be possible to attain the highest yield potential of shattering tolerant sesame genotype in high and low plant density.

In future climatic conditions, rice yields depend on environmental conditions of the growing season, such as temperature and available radiation rate, which in unfavorable conditions can lead to yield loss in some rice producing countries (Welch et al., 2010). Achievement to the appropriate plant density per unit area is one of the methods in increasing crop yields through crop management that as a result, all environmental factors fully utilized, while intra- and inter-plant competitions be minimized and on the other hand, suitable plant density can provide sufficient space for agronomical operations and high quality access. In general, suitable rice density is a density that is not detrimental for proper crop development and high grain yield. As the density increased, the number of primary and secondary panicles and spikelet per panicle decreased and the number of panicles per m2 increased linearly and with decreasing density, stem thickness increased (Ebrahimi Rad et al, 2018). Knowing the heat indices, such as the accumulated heat unit, which in most sources are referred to as growing degree days (GDD), can provide basic principles for determining the appropriate phenological stages and planting dates. Evaluation of cumulative GDD for different development stages will allow adjustment of planting date for rice genotype with the aim of adapting the environmental conditions in the growth period. Choosing the appropriate planting date is one of the important factors in effective crop management which has a great role in production control by adapting physiological, morphological and phenological processes of the plant such as germination and emergence, vegetative growth, flowering and maturity with favorable climatic conditions. Management of planting time for optimal production of each cultivar is one of the main factors affecting production that can be easily managed by the farmer based on environmental conditions. Proper planting date will optimize the use of yield factors, while inappropriate planting date will disrupt the balance of yield components in the plant (Esmaeilzadeh et al., 2017). In order to determine proper transplanting date based on GDD and the best plant density in rice (Tisa cultivar), an experiment was conducted at Rice Research Institute of Iran, Tonekabon station during 2015 and 2016. This experiment was carried out as split plot in a randomized complete block design with three replications. The main plot was three transplanting dates with 10 days intervals (May 4, May 14 and May 24) and the sub plot was allocated to plant density at three levels (12×30, 15×30 and 18×30 cm). The results indicated that there was a significant difference between the years of experiment only for the panicle length. The effect of transplanting date was significant in the majority of the measured parameters. The highest grain yield (6573.6 kg/ha) was obtained on May 24 planting date, which did not show any significant difference with the transplanting date of May 14. Although plant density treatments had no significant effect on grain yield, 28 plants per m2 (30×12 cm) had the highest grain yield (6445.2 kg/ha). With delay in transplanting, GDD and number of days from transplanting to tillering stage as well as the time required for panicle emergence and complete maturity increased. The highest and the lowest growth degree-day (GDD) from transplanting to tillering, panicle emergence and full ripening stage were obtained on May 24 and May 4, respectively. According to the results of this research, it can be stated that the farmers of the region can transplant this cultivar between May 14 and May 24 with a plant distance of 12×30 cm (density of 28 plants per square meter).

In order to study effects of various levels of nitrogen and sulphur fertilizers on quantitative and qualitative characteristics of castor bean (Ricinus communis L.), an experiment was done in 2015 at reaearch farm, agricultural faculty of Azarbaijan Shahid Madani University, Tabriz-Iran. Experiment was conducted as a factorial based on randomized complete block design with three replications. Treatments were 4 levels of nitrogen (0, 50, 100 and 150 kg ha-1) and 5 levels of sulphur (0, 20, 40, 60 and 80 kg ha-1). Results indicated that maximum biological and seed yield, seed oil percentage and yield and appropriate percentage of seed crude protein obtained from applying 100 and 150 kg nitrogen per hectare. In contrast, application of 40 kg sulphur ha-1 was enough to reach maximum amounts in seed yield, HI, seed oil percentage and oil yield. Application of sulphur fertilizer had not significantly effect on seed crude protein. Maximum agronomic efficiency of nitrogen and sulphur was achieved when nitrogen and sulphur were applied at a rate of 150 and 40 kg ha-1, respectively. Interaction effects of nitrogen and sulphur showed that applying 150 kg nitrogen by 60 kg sulphur ha-1 resulted in the highest biological yield, seed and seed oil yield in castor bean. The overall conclusion of this experiment showed that presence of nitrogen and sulphur around the castor bean roots can cause an incease in leaf area, photosynthesis and biomass during the growing season, seed and oil yield at the end of the growing season.

To study the effect of sowing date on yield, yield components and agronomic traits of oilseed rape promising hybrids and lines, an experiment was conducted at Agricultural Research Station of Gorgan during 2010–2011 and 2012-2013 cropping seasons. The experiment was a randomized complete block design arranged in split plot. Four genotypes Hyola 50, Hyola 420, L5 (Varamin) and L6 (Zabol) were as sub plots and five sowing dates 23 Oct., 11 Nov., 1 Dec., 21 Dec. and 10 Jan., were as main plots. The mean air temperature during germination time for sowing dates 23 Oct., 11 Nov., 1 Dec., 21 Dec. and 10 Jan was 19.5, 14.7, 13.8, 8.8 and 6.8 oC in 2010–2011, and 20.5, 15.1, 12.2, 6.8 and 8.56.8 oC in 2010–2011, respectively. In both years, seed yield, aboveground dry matter and harvest index decreased with delay in sowing date. In the first year, the first sowing date had the highest (4070 kgha-1) and last sowing date had the lowest (2323 kgha-1) seed yield. Similarly, in the second year, the first sowing date had the highest (4125 kgha-1) and the last sowing date had the lowest (2319 kgha-1) seed yield. The mean seed yield of Hyola 50, Hyola 420, L5 and L6 was 3534, 3329, 2977 and 3147 kgha-1, respectively. The mean harvest index of Hyola 50, Hyola 420, L5 and L6 was 30.6, 29.2, 27.9 and 29.1%, respectively.

To study the response of bread wheat cv. Azar2 to row spacing and seeding rate and to determine the desirable density under cold rainfed conditions a two-year study (2008 and 2009) was carried out in Qamloo research station located in Kurdistan. Four rows spacing including 15, 17.5, 20 and 25 cm as horizontal factor and four seeding rates including 350, 400, 450 and 500 seed/m2 as vertical factor were assigned. Row spacing had significant effect on grain yield, spike per square meter and harvest index. Seed rate was not significant except for thousand kernel weight. The highest and the lowest grain yield values, 3506 and 2624 kg/ha, were observed in rows spacing of 15 cm and 25 cm, respectively. Row spacing of 15 cm with 638 spike/m2 and 29 g TGW was located over the others. The highest grain per spike (22 grain) were observed in rows spacing of 25 cm. Because of no significant difference among seeding rates, the best recommendation of Azar2 planting type for cold high elevation rainfed areas is row spacing of 15 cm and seeding rates of 350-400 grain /m2 or 140-160 kg/ha.

In order to investigate the effect of row spacing and seeding rate on Mesa-Sirsa alfalfa cultivar, this experiment was carried out in the research farm of Khuzestan Agricultural Research Center between 2000 and 2004. The research was performed in the form of a split plot in a randomized complete block design with 3 replications. The main plots were three row spacing’s (50, 60 and 70 cm) and the sub plots were five seeding rates (5, 10, 15, 20, and 25 kg seed per ha). The Traits were racemes lm2, pods/raceme, seeds/pod, 1000 seed weight, seed and biological yield and hoarest index. The effects of year were significant different on all the traits. Seeding rate did not have any significant effect on pods/raceme, seeds/pod and 1000 seed weight. The highest seed yield was obtained from 50 cm row spacing. Seed and biological yield increased as row spacing. Decreased using the highest seeding rate (25 kg/ha) produced the highest biomass yield (5034 kg/ha). The highest significant correlation was observed between race/ms/m2 and seed yield (r= 0. 922٭٭). According to the results, for alfalfa (var. Mesa-Sirsa) seed production in South Khozestan province, using 15 kg/ha seed and 50 cmrow spacing, that produced the highest seed yield due to increase in race/ms/m2 and 1000 seed weight, is recommended.

Conservation tillage، a fast growing practice in Iran، is considered as a means to achieve sustainability in agricultural systems. This study was carried out to determine the effect of tillage systems (No-tillage، Minimum tillage and Conventional tillage) on yield and yield components of three irrigated wheat varieties. The field experiment was conducted at the experimental station of the University of Tehran in 2010. The experimental design was RCBD in split-plot arrangement with four replicates. Three different Tillage systems including conventional، minimum tillage and no-till were applied in main plots. Wheat cultivars (Pishtaz، Pishgam and Bahar) were sown in sub plots. The results showed a significant difference amongst different method. Grain yield، number of spikes per square meter، biological yield، harvest index and 1000 grain weight were higher in conventional than the other two systems P

To study the effect of limited irrigation regime and nitrogen fertilizer on the yield and yield components of sorghum var. Payam، a field experiment was conducted in 2008 at experimental farm of college of agronomy and plant breeding، university of Zanjan. The experimental design was a split Plot based on a randomized complete block design with three repetitions. In this research four irrigation regime including full، light limited، moderate limited and severe limited irrigation، were assigned to the main plots and five nitrogen level including 0، 50، 100، 150، and 200 Kg/ha were assigned to the sub plots. The results showed that irrigation regimes and nitrogen fertilizer had significant effects (p≤ 0. 05) on grain and biological yield and yield components of sorghum. Grain and biological yields decreased with decrement in irrigation frequency from full to severe limited irrigation and increased with increment in nitrogen level from 0 to 200 kg/ha. The highest grain yield (8. 43 ton/ha) was obtained from 200 kg/ha nitrogen and full irrigation regime that had not any significant difference with 150 kg/ha nitrogen and full irrigation regime. The lowest grain yield (4. 6 ton/ha) was obtained from 200 kg/ha nitrogen and severe limited irrigation regime.

Resistance or adaptability of varieties for cultivation are used due to more efficiency in salinity soil. This trails was carried out in randomized complete block design with four replications، 12 canola varieties، in salinity soil with 11. 2 ds. m-1 and without salinity soil limitation in two years during 2004-2005 and 2005-2006 in Khouzestan agricultural research center. Two years compound analysis results were showed significant difference in yield and yield component in each location for all varieties. Salinity limitation were reduced germination 6. 5 percent، 2. 9 day flowering duration، 2. 5 day maturity، 45. 6 centimeter plant height، 23. 8 pod per plant، 2. 1 seed per pod، 0. 95 gram thousands seed weight، 1174. 9 and 433. 7 Kilogram seed and oil yield per hectare. All canola’s varieties were sensitive to salinity based on Fischer index except option500 and pp-401/15E. In spit of this results، the Hyola Hybrids were recommended four two both environmental conditions، according theories high yield potential and early maturity and in other hand RGS003 verity was recommended for salinity soil of south Khouzestan.

To determine the effects of different levels of irrigation and streptomyces bacterium on grain yield and its components of maize cv. KSC260 a field experiment was carried out. The experiment was carried out as stripe split plot arrangments in randomized complete block design with three replications in 2009 and 2010 growing seasons in Seed and Plant Improvement Institute Karaj, Iran. Experimental factors included: three levels of irrigation (A); 70, 100 and 100 mm evaporation from standard evaporation pan (class A) as optimum, mild stress and severe stress, respectively, and four bacterium treatments (B), control (no chemical fertilizer and no bacterium), fertilizer, bacterium + fertilizer and bacterium. Results showed that irrigation levels significantly (P < 0.01) affected leaf dry weight, leaf area index, leaf chlorophyl index, plant height, ear length, ear diameter, biological yield, kernel no. row-1 1000 kernel weight and grain yield. Irrigation levels also significantly (P < 0.05) affected days to silking, anthesis to silking interval, ear height, stem diameter and ear no. plant-1. Bacterium treatments also had significant (P < 0.01) effect on days to anthesis, days to silking, leaf number, leaf dry weight, leaf area index, leaf chlorophyll index, stem diameter and ear diameter. It also had significant (P < 0.05) effect on days to tasseling, ear number, row no. ear-1, 1000 kernel weight. The highest and lowest grain yields were obtained from optimum irrigation (5649 kgha-1) and severe stress (3574.5 kgha-1) conditions. It was concluded that the highest performance of cv. KSC260 was in optimum irrigation with application of Streptomyces bacterium and nitrogen and phosphorous.

In order to evaluate the best sowing date and its effect on yield and yield components of sunflower cultivars, a field experiment was done as split block design in a randomized pattern of complete block design with three replications in 2009 in Shahinshahr , Isfahan. The sowing date was studied in four intervals : 22 June,2009, 1 Jul,2009,11 Jul,2009, and 21 Jul 2009. The four factors used were, Alestar, Azargol, Master and Zaria. The results showed that sowing date had a significant effect on the number of seed, weight of thousand seeds, seed yield, LAI, Cap diameter and oil percentage. The higher seed yield (4170 kg/ha) was obtained from the first sowing date (22 June.2009), and the lowest seed yield (2230 kg/ha) was obtained from the last sowing date (21 Jul.2009). The average of seed yield in 1 Jul.2009 and 11 Jul.2009 was 3980 and 2760 kg/ha. The highest number of seed (759.5) and weight of thousand seeds (55 gr) was obtained from 22.June.2009 and the lowest number of seed (619.3) and weight of thousand seeds (36 gr) was obtained from 21.Jul.2009. The cultiver had a significant effect on all studied traits except the number of seeds. The highest and lowest seed yield were related to Azargol (4090 kg/ha) and Alestar (2450 kg/ha). The seed yield of Zaria and Master were 3500 and 2910 kg/ha. The highest and lowest weight of thousand seeds was obtained from Azargol (57 gr) and Alestar (38 gr).

In order to study the effect of sowing date on yield and yield components of sorghum cultivars, a field experiment was conducted at experimental field of agriculture factuly, Tarbiat Modares University which is located in 17 km Tehran-Karaj freeway. In this research effect of two factors, sowing date and cultivars of sorghum bicolor, was studied in split-plot based on randomized complete block design with 4 replications. Main plots were sowing date with three levels (8th June, 28th June and 18th July) and sub plots were cultivars with three levels (Payam, Sepideh and Kimia). Investigated traits include biological yield and its component, panicle weight, grain yield, percent and yield of protein, harvest index and grain yield component. Result showed that total biomass and vegetative biomass were not affected by any of factors. panicle dry weight and harvest index was significantly affected by cultivars (p≤0.01) although in grain yield was significant in 95 percent level. Weight of 1000 seeds was also affected by sowing date and cultivar (p≤0.05) and was affected by sowing date × cultivar interaction (p≤0.01). In spite of non significant effect of sowing date on grain yield, the highest grain yield was obtained by Sepideh in 28th June. In the result for higher grain yield in this region and other places with similar conditions, sowing Sepideh cultivar in mid June is recommended.

To determine the effect of zinc and auxin foliar application on grain yield and its components of grain maize (Zea mays L.) cv. SC 704] under water deficit condition, this study was conducted in Agriculture Research Center of Varamin in south–east of Tehran in 2006 crop cycle. There were three water deficit levels: 50%, 60% and 70% water depletion of available water in soil (main-plots), factorial of zinc and auxin foliar application (sub-plots) (zinc foliar application in four levels: sulphate, EDTA, water spraying and no spraying and auxin spraying in three levels: spraying, without spraying and water spraying, respectively) arranged in a split plot–factorial using randomized complete block design with three replications. Results showed that only water deficit × auxin spraying interaction was not significant on grain yield and grain protein and oil contents. Zinc (sulphate and EDTA) × auxin spraying interactions in 50% and 60% water depletion of available soil water had the highest grain yield with 12410 and 11840 kgha-1, respectively. In addition, the effect of two zinc complex and auxin spraying in different water deficit levels on grain yield and yield components varied, but showed positive effect on grain yield and its components at the same water deficit levels.

In order to investigate genetic correlation and path analysis between grain yield and yield components, fifteen early maturing hybrids of grain corn (Zea. mays) using a randomized complete block design with 4 replications were evaluated in Khoramabad agricultural research center, Iran. The data were collected and analyzed for ear emergence date, anthesis date, maturity date, plant height, ear height, plant stand, ear cover, grain number per row, row number per ear, grain depth, 1000- grain weight, plant value, cob percent, grain yield, stay green, stem and leaf resistante to disease. The results showed grain yield was positively correlated with plant height, ear height, grain depth, row number per ear, grain number per row, but negatively with 1000-grain weight, ear cover, cob percent and stay green. Between emergence date and maturity date and It was observed significant negative correlation stay green and leaf disease and positive significant correlation with ear height, grain depth and ear cover, suggested that late maturing hybrids with higher productivity were more resistante to diseases. The results of regression and path analysis showed that 1000-grain weigh and cob percent were correlated with yield negatively, and grain depth, plant height and plant stand were positively (R2=0.52) and had higher effects on grain yield.

In Other to determine the effect of zinc foliar application (Zinc-Fousin 70%) in various rate (0, 0.5, 1 and 1.5 liter per hectare) and various stages of growth (V8-R3) on yield components, yield, oil and protein percentage of two soybean cultivars [(Sahar, Determinate) (Williams, Indeterminate)] in summer cultivation in 2004 at Gorgan, Golestan, Iran. The treatments were arranged in a Factorial Split Plot design based on randomized complete blocks (RCBD) with four replication. The results indicate that zinc foliar application in V8, significantly increased, number of seed per pod, seed yield and harvest index. Also one liter zinc foliar application per hectare significantly increased plant height and percent of seed protein. Cultivar Sahar was superiour than Williams for number of pod per plant, seed yield, percent of seed protein and harvest index. Also, Cultivar Williams for number of seed per pod, number of nod in main stem, plant height and percent of seed oil was superior to cultivar Sahar. positive and significant correlation was observed between seed yield with number of pod per plant, number of seed per pod, one thousand seed weight and harvest index. Among yield components, seed weight (for Williams) and pod number per plant (for Sahar) had the most correlation with seed weight.

In order to investigate effects of water stress, nitrogen fertilizer and manure and mixed nitrogen fertilizer and manure on chlorophyll meter reading, grain yield and yield components of grain maize cv. SC 704, a field study was conducted in 2005 and 2006 cropping seasons. A randomized complete block design with factorial arrangement with three replications was used. Treatment consisted of four levels of nitrogen fertilizer (0, 92, 184 and 276 kg N ha-1), mixed nitrogen fertilizer and manure (46 kg N ha-1 + 2.5 tons ha-1 farm yard manure (FYM), 92 kg N ha-1 + 5 tons ha-1 FYM and 138 kg N ha-1 +7.5 tons ha-1 FYM) and Farm Yard Manure (5, 10 and 15 tons ha-1 FYM) three levels of irrigation (optimum irrigation (control), water stress 75% crop water requirement and water stress 50% crop water requirement). Results showed that decreasing in nitrogen with water stress reduced plant growth. Maximum growth was observed when nitrogen and adequate water for maize crop was applied. Chlorophyll meter readings were significantly higher when water stress and nitrogen increased, and had a linear relationship with kernel nitrogen percentage and was affected by water supply. The results also showed the maximum grain yield was obtained in 138 kg N ha-1 + 7.5 tons ha-1 FYM with an average of 7555 and 7912 kg ha-1 in the first and second years, respectively. Maximum grain yield was observed when optimum irrigation was applied with an average grain yield of 8756 and 9462 kg ha-1 in the first and second years, respectively. When water stress was applied at 50 and 75% of optimum irrigation, grain yield was decreased by 63 and 41% in first year and by 66 and 41% in second year. The maximum grain yield was obtained in 138 kg N ha-1 + 7.5 tons ha-1 FYM and optimum irrigation with an average grain yield of 11790 and 12360 kg ha-1 in the first and second years, respectively. Results indicated that adequate nitrogen fertilizer slightly increased grain yield under water stress. Integrated nitrogen and FYM application increased grain yield under water stress but optimum irrigation increased grain yield. Under severe water stress condition nitrogen applied as integrated nitrogen fertilizer and manure increased grain yield. Integrated nitrogen fertilizers and manure, reduced the needs for chemical fertilizers and produced higher grain yield. It is concluded that application of 138 kg N ha-1 + 7.5 tons FYM ha-1 at optimum irrigation decreased the needs for chemical N fertilizer by 50%. It also increased the grain yield and water productivity by 6.2 and 6%, respectively in the first year and by 4.1 and 4.2% in the second years, as compared to the 276 kg N ha-1.

In this study thirty three wheat cultivars were compared for osmoregulation capability using the ratio of projected pollen grains area under water stress to normal conditions. Digital images of pollen grains obtained from plants grown under well watered condition, were analyzed to obtain their projected areas. Field experimental arranged in a split-plot (cultivars were assigned to sub-plots and drought stress to main plots) in order to compare cultivars grain yield under water stressed and well watered conditions. Based on the results of pollen area ratio, cultivars were divided into two groups. Cultivars, Dez, Kavir, Roshan, Back Cross Roshan (winter type), Zarrin, Pishtaz, Omid and Alvand were classified as capable for osmoregulation as they had a ratio of higher than unit, while the others were grouped as incapable since had ratio lower than unit. Results of ANOVA showed that drought stress and cultivar had significant effects on grain yield and its components as well as biological yield and harvest index. In general, drought stress significantly reduced the grain yield. On the other hand, average grain yield of osmoregulation capable group was 1.73 times greater than that of incapable group. Meanwhile, significant correlation coefficient (r = 0.29**) was found between projected pollen area and grain yield under drought stress condition, implying that increased grain yield could be attributed to osmoregulation capability. Wheat cultivars grouped as capable for osmoregulation are suggested to be used in breeding programs for increasing drought tolerance.

This experiment was carried out for evaluation of the effect of rate and time of nitrogen application on grain yield and yield components in spring safflower in Shirvan-Chardavol in Ilam during 2002-2005 cropping seasons. Experimental treatments were arranged as factorial in complete randomized block design with three replications. Nitrogen rates (50, 75, 100, 125 and 150 Kg.ha-1) and split application of nitrogen in three levels (first split: 50%: 50% ratio at pre-planting and late rosett, second split: 50%: 50% ratio at preplanting and early flowering and third split: one-third: one-third: one-third ratio at pre-planting, late rosett and early flowering). Combined analysis of variance indicated that interaction of nitrogen rate × split application was significant (p<0.05) on grain yield. Mean comparison showed that 100 Kg.ha-1 of nitrogen with triple splitting application at pre-planting, late rosett and early flowering stages produced higher grain yield (2752 Kg.ha-1). This was achieved due to increase in head/m2 (240 heads), grain/head (36.3 grains), and 1000 grain weight (34.4 g). Application of 100 kg.ha-1 nitrogen and its triple splitting produced the highest oil yield (755 Kg.ha-1).