JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2013 | Volume:5 | Issue:2|Papers Count:8

In order to study the effect of sowing date and plant density on yield and its components of canola cultivars, an experiment was carried out using a split plot factorial based on completely blocks design with three replication at Kusk field of eghlid in 2011-2012. Sowing date were assigned to main plots at three levels (August 23, September 1 and September 11), three levels of plant density (44, 67 and 133 plants/m2) and three cultivars (Talaye, Okapi and Likord) as factorial were randomized in sub-plots. The results showed that sowing date had significant effect on all traits. Increasing of plant density increased plant height, pods per m2, biological and seed yield and decreased oil percent. Intraction of sowing date and plant density showed that highest seed yield produced in first and second sowing date was at 67plants/m2, while 133plants/m2 had highest seed yield at third sowing date. Generally, sowing date of September 1 for Okapi cultivar and plant density of 67plant/m2 can be recommended for conditions of Eghlid region.

In order to determine the ecological effects of concentration and time of herbicide application for weed control in corn, a field experiment under natural infestation of weeds was conducted in Shahr-e-Rey (Jafar Abad) and Varamin Farms. The experiment was conducted as split plots in the basis of completely randomized blocks design in 3 replications. Using Atrazine herbicide contains 4 levels (0, 1, 2 and 3 Kg. ha-1) as main factor and 3 different herbicide times application (After planting and before germination, 3 weeks after planting and 6 weeks after planting) as sub factor were considered. The results of variance analysis indicated that, the effect of timing and concentration of herbicide application and interaction of them on all measured traits (Plant height, stem diameter, ear corn length, ear corn diameter, number of rows per ear corn, number of grains per row, number of grains per ear corn, grain and total dry weight and grain yield) were significant. Two times of herbicides application, after planting and before germination and 3 weeks after planting had positive significant effect to the third timing of herbicide consumption. There were not significant difference between 2 and 3 kg/ha herbicide applications. Except in dry weight and grain yield traits which in the time after planting and before germination application for 3 Kg.ha-1 had better result, In other cases later herbicide application had less succesfully. Two or three kg/ha of atrazin after planting and before germination spraying showed positive results in weeds control during the first few days critical period of corn growth.

An experiment to investigate the effect of dual-use chemical herbicides Total, Asrt, Apyrvs and Shovalieh And evaluate their performance with conventional herbicides Topic + Granstar on pishtaz wheat yield, and Yield component Resistance occurred in the region of Ilam, Ilam Chardavel was implemented in the 2011-2010 crop year. Experiment in a randomized complete block design with 6 treatments and 6 replications. Experiment treatments included: Control without the use of herbicides, Apirous with consumption doze of 26.6 gr per hectare, Shavaleieh with consumption doze of 400 gr per hectare, Asert with consumption doze of 2.5 liter per hectare, Total with consumption doze of 40 gr per hectare, Topic + Grainstar with consumption doze of 8 liter + 25 gr per hectare. Sitogit was used with Apirous, Shavaleieh and Total by 2 per 1000, According results of this Experiment the highest and lowest broadleaf weed control treatments, respectively, was owned the total and Apyrvs, The highest and lowest elongated leaf weed control treatments respectively belonged total Asrt and a total of the highest and lowest total control of broadleaf weeds and leaves were elongated was owned total treatment and the asrt treatment. Wheat in total treatment had maximum and Asrt Treatments lowest yield, seed weight and harvest index. Therefore according to the continued use of a mixture of two herbicides topic + Granstar caused biotype resistant is to this herbicides in weeds in the province, Therefore, the results of this experiment in order to reduce the resistant biotype harmful effects on the environment and reduce can be arranged Shavaleieh of the total herbicides and two herbicide mixtures suitable for topic + Granstar know.

In order to comparison of low and optimum temperature effect on morphological traits and yield of rice varieties at different growth stages, an experiment was performed as split plot factorial based on completely randomized design (CRD) in green house of Iran’s rice research Institute (Amol) During 2010, in three repetitions. This treatment included 5 rice varieties as main factor in order Shirudi, Fajr, local Tarom, Hybrid and line 843 and 2 levels of temperature T1 and T2 in order 13 and 32oc along with 5 levels of growth G1 to G5 in order, after transplanting to tillering, stem elongation, booting, flowering, grain filling that were as two sub factors. Three seedlings were planted in each pot. At the first, all of them were kept in normal temperature then they were kept in 13 c° for 15 days then they were transferred to 32 c° place. After treatment temperatures in each growth stage plant height, number of tillers and leaves per hill, shoot and leaf dry weight in hill and after harvesting panicle length and yield were measured. The analysis of variance results show that the effects of cultivar, levels of growth and temperature and their interactions effects on all morphological characters are significant at one percent level of probability. Interaction effect of variety and temperature showed that most tolerant variety in relation to temperature stress along with least percentage yield (19%) is shirudiy variety and the most sensitive variety in relation to stress with most percentage of yield decrease (29%) was local tarom. By reducing the temperature from 13oc to 32oc plant height, number of tillers and leaves per hill, number of green leaves in the hill, shoot and leaf dry weight in hill were decreased.

This experimental was done as split plot in the basis of completely randomized blocks design with tree replicattion in Mazandaran province in 2009. Main factor was sowing date (Auguest 16, 24, 31 and 7 September) and sub factor was row spacing (65, 75 and 85 cm). The results showed that maximum of the plant height and plant dry weight was obtained on Auguest 16 and most of the ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index were obtained on Auguest 24. Most of the plant height, ear length and plant dry weight were conducted in rows space of 65 cm and maximum of grain number per row, grain weight, green ear yield and harvest index were obtained in row space of 75 cm. Maximum of the plant height and plant dry weight were obtained on interaction effect of the 16 Auguest and rows space 65cm. The most amounts of green ear yield and grain yield were obtained on interaction of the Auguest 24 and rows space 75 cm. Sowing date 24 Auguest introduced the best treatment, because in this sowing date increased ear diameter, grain number per row, grain number per ear, grain weight, green ear yield and harvest index that introduce as the most important traits of sweet corn. The Rows space 75 cm determined as the best because in this treatment grain weight, green ear yield and harvest index increased.

To evaluate the effect of external application of salicylic acid and drought stress on yield and yield component of sunflower (Helianthus annuus L.), Hayson 25 cultivar, an experiment was conducted as split plot in the basis of completely randomized block design with three replications at Natural Resources, Agricultural Research Station, Sabzevar during 2010-2011. Experimental factors were drought stress as irrigation intervals: without stress (6 days interval), moderate stress (12 days interval) and intensive stress (18 days interval) and foliar application time of salicylic acid (SA) as 0.724 Mm in four levels (Control, foliar application in vegetative stage, foliar application in flowering stage and foliar application at vegetative+flowering stages). The results showed that the increasing of irrigation intervals from 6 to 18 days decreased seed yield, biological yield, seed per capitul and seed weight statistically, while the percentage of oil didn't show particular reaction to irrigation intervals. Six days interval irrigation produced the highest yield and yield components. Yield and yield components of sunflower had different response to SA foliar application time. The plant height, biological yield and seed per capitul were obtained with SA foliar application at vegetative stage, while foliar applications in the flowering stage has maximum seed yield, seed weight and oil percentage. As a result, once exogenously applied SA as foliar application in vegetative or flowering stages mitigated the adverse effect of drought stress.

To investigate the effect of nano potassium application methods on yield and yield components of wheat cv. Chamran, a field experiment was conducted in Sabzevar. Experiment was carried out as split plot in a randomized completely block design with three replications. Experimental factors included three levels of potassium soil application (No application, 150 kg.ha-1 potassium sulfate and 10 kg.ha-1 nano potassium) and four levels of nano potassium foliar application (no application, foliar application at tillering, foliar application at stem elongation and foliar application at tillering and stem elongation). The experimental results showed that soil application of potassium had significant effects on plant height, reproductive tiller number per plant, one hundred seed weight, economic yield and biological yield, but had no significant effect on spike length and seed number per spike. Soil application of potassium sulfate and nano potassium improved vegetative growth, yield and yield components of wheat. Foliar application of nano potassium had significant effect on all characteristics, except one hundred seed weight. Foliar application of nano potassium at tillering and tillering +stem elongation stages significantly increased economic yield. According to the results, soil application of potassium sulfate or nano potassium along with foliar application of nano potassium at tillering stage can be recommended to maximum wheat economic yield.

An experiment was conducted to evaluate the effects of concentration time and spraying methanol on growth and yield of cowpea (Vigna unguiculata L.) in 2009. This research was done as a two factors factorial experiment in a basic plan of completely randomized blocks design in three replications in Rasht region. The factor methanol concentraition was considered at four levels: 0, 10, 20 and 30% methanol) and the time of methanol application factor in three levels: Spraying in the morning (8:00-10:00 a.m.), at noon (13:00-15:00 p.m.) and in the afternoon (17:00-19:00 p.m.) and. The results showed that concentration and time of methanol spraying effect on pod and seed yield of cowpea. Among methanol concentration treatments, maximum pod and seed yield amounts 1743.81 and 930.54 kg/ha were recorded for the 20% and 30% methanol treatments, respectively. Furthermore, the spraying in afternoon resulted in the highest pod and seed yields amounts to 1649.56 and 902.42 kg/ha, respectively.