Impact of different herbicides on morphological and biochemical parameters of wheat and weeds control

The present study was conducted to evaluate the effect of different herbicides on morphological and biochemical characters of wheat (Triticum aestivum L., varity: Sahar-2006) and control of weeds. The variety Sahar is a local developed variety and as per the Institute of Biotechnology and Genetic Engineering, this variety is very much suited for Peshawar valley in terms of its productivity. The experiment was laid out in Randomized Compete Block Design (RBCD) with three replicas, each with seven plots. Five different herbicides at the rate Clodinafop 100 gm/6-liter, Affinity 100 gm/liter, Isoprotron 50% w/w 100 gm/6 liter, Bromoxynil 62.5 ml/6 liter, MCPA 62.5 ml/6 liter of water, Hand weeding and Weedy check were used. Weed density was calculated before and after of treatment of different herbicides. Maximum weed (97 %) was controlled in plots treated with Bromoxynil. Number of tillers/plants, spike length, number of spikelet’s/ spikes, plant height, number of nodes/plant and stem width were non-significantly affected by herbicides. Maximum spike length (9.53 cm), number spiklets/spike (18.97), plant height (89.10 cm), number of nodes/plant (5.57), leaf width (1.53 cm), stem width (1.49 cm) and grain yields (kg/m) were noted in weedy check. Maximum number of tillers/plant (11.33), number spiklets/spike (18.97) and grains/spike (51.87) were noted in hand weeding plots. Clodinafop showed positive correlation with weedy check and hand weeding plots for the number of tillers (6.67), spike length (9.07 cm), plant height (87.60 cm), leaf length (42. 37 cm), leaf width (1.53 cm), 1000-grains weight (51.37 gm) and total grains yields (2.42 kg/ha). Maximum moisture (8.90 %) and fats (2.6 %) for Clodinafop, maximum fibers (6.8 %) for MCPA and maximum protein (15.28 %) for Isoprotron treated plots were recorded. Isoprotron, Affinity and Bromoxynil showed similar results (1.8 %) for Ash contents. Highest value 71.81 % and 71.52 % of carbohydrates were recorded in hand weeding and weedy check plots respectively.


Introduction
Wheat (Triticum aestivum L.) is one of the most important staple foods of mankind.It is also known as "The king of cereal".About 37% of the world population depends on it as their main cereal crop.Wheat whether cultivated or wild belongs to the genus Triticum.Wheat is an annual self pollinated long day crop.Plant body consisting of rolled or rounded shoots, fibrous adventitious roots and leaf with sheet ligules and leaf blade lamina.The plant as a whole is glabrous.Depend on fertility of soil, wheat produces tillers like other grasses [1].It is the indispensable and regarded as the world leading food crop because of its antiquity.It has been suggested that the demand for wheat crop in the year 2020 will be ratio from 840 million tons to 1050 million tons [2].It occupies a central position in the crop and plays a very important role to meet the need of food requirement.Wheat ranks first in all cereal crops and annually it occupies 66% of crop area in Pakistan [3].Wheat kernel contains 10-15% Proteins, 63-71% Carbohydrates, 1.5-2% Fats, 1.5-2% Minerals, and 20-25% Vitamins.Of the average diet, wheat supplies (73%) calories and proteins [4, 5].On the basis of area and production of wheat, Pakistan ranks 8 th , out of the 121 countries of the world.On the basis of yield per unit area, Pakistan ranks 9 th , throughout the world.Pakistan occupies 6 th position and a populous country, where wheat is used as a primary source of food

Study area
To study the impact of different herbicides on morphology and proximate components of wheat and weed control.A field experiment was conducted at Botanical Garden, Islamia College University, Peshawar during Rabi season 2011-12.Location of the experimental site was at 34 0 N and 71.3 0 E and an altitude of 347 m ASML.Coordinates of the area from which plants were collected: 34.0000° N, 71.4760° E.

Experimental procedure
Procedure of the experiment was carried out in two main steps.1. Field experiment 2. Biochemical analysis

Experimental design
The experiment was laid out in Randomized Complete Block design (RCBD) with three replicas.In each replication there were seven sub plots having five for herbicides application, one hand weeding and weedy check plots.Each plot had eight rows.The size of each plot was (3 x 1.5) m 2 .A distance of 30 cm was kept among the rows.

Preparation of the soil
The soil of the experimental site was well prepared by ploughing.A basal dose of nitrogen fertilizers in the form of nitrate was used at the time of seed sowing.In well prepared seedbed of soil, wheat (variety: Sahar-2006) was sown by hand at the rate of 120 Kgha -1 on November 26 th 2011.There was sufficient amount of moisture in the soil while sowing the seed.Seeds were sown in rows and depth of the seed in the soil was kept 5 cm.

Seed germination
Germination of the seed started on December 7 th 2012, just before first irrigation urea fertilizer was applied to the field.Canal water was used for irrigation purpose.On the basis of water need second, third and fourth irrigation were providing to the field during the entire experimental period.

Weeds in the experimental site
During the course of study of the experimental site, different types of weeds were observed.These weeds were as follows.
Allium The following data of weeds was recorded before and after the application of herbicides: 1. Weed density and relative weed density 2. Frequency and relative frequency 3. Canopy cover and relative canopy cover Weed density Weed density was calculated when wheat was at 4-6 leafy stage.Weed density was calculated by quadrat method.Quadrate used during this experiment having size of 20 cm length and 10 cm width (0.02m -2 ).All treatments of three replications were taking into account while calculating weed density.In each treatment quadrat was placed five times randomly and then weeds inside the quadrat were counted.Density for each individual species and that for different species inside the quadrat was calculated as a whole.

Herbicides and other methods used in the experiment
Following five different types of herbicides were used for the controlling weeds in the study area (Table 1).

Formula for calculating weed density, frequency and canopy cover
For calculating weed density the following formula was used.

Soil analysis
To study the nature of the soil of the experimental site, soil samples from different treated plots were taken to the depth of 15 cm.Collected samples of soil were air dried, cleaned off from stones and plant residues were grounded in a stainless steel grinder and passed through 2 mm sieve.The sieved soils were collected, sampled and stored in plastic bottles.Soil was analyzed for soil texture, pH, organic matter, soil nitrogen and electrical conductivity, Soil texture =  3).

Stem width (cm)
Statistical analysis of the data showed that stem width was significantly affected by different herbicides treatments (Table 4).Maximum stem width (1.49cm) was found in weedy check as compared with hand weeding plot with stem width (1.46cm).Among the herbicides treated plots, stem width (1.37cm) for Bromoxynil, (1.30cm) for Clodinafop, (1.12cm) for Isoproturon and (1.13cm) for Affinity were recorded.It was concluded that herbicides have significantly effect and suppressed stem width as compared to control.

Thousand Grains weight
Analysis of variance of the data showed that herbicides have no significant effect on 100grains weight.Highest 1000 grains weight (51.47g) was recorded in hand weeding and (50.57g) was found in weedy check plots.Lowest 1000 grain weight (44.70g) was found in Affinity treated plot.Data recorded for other treatments were comparable with each other and no significant differences were found.Qureshi [28], Hassan [29] and Marwat [19] stated that herbicides application increased 1000 grain weight significantly when compared with weedy check.Grain yield (kg/m²) Results showed that herbicides have significant effect on the grain yield (Fig. 2).Maximum grain yield (2.6kg/m²) was obtained in weedy check plot closely followed by hand weeding (Table 5).In    3).

Ash contents
Ash obtained from different herbicides treated plots showed that application of herbicides has a significant effect on ash contents.Results revealed that maximum ash (1.8%) were found in Isoproturon, Affinity and Bromoxynil treated plots followed by (1.6%) in Clodinafop and MCPA treated plot.Minimum ash contents (1.3%) were found in hand weeding plot and weedy check (1.4%) (Fig. 3).It was concluded that ash contents have increased in herbicides treated plots as compared to control.

Fats contents
Analysis revealed that herbicides application has non-significant effect on fats.Maximum fats contents (2.6%) were found in Clodinafop while minimum fats contents (1.2%) were noted in Bromoxynil treated plots.Same value was recorded for fats contents (2.4%) in herbicides treatment plots.It was probably due to the effective control of weed by herbicides as a result of the may have absorbed and utilized the available resources for fats content.

Fibers contents
Data regarding the fibers contents of wheat flour showed that different herbicides treatments significantly affected the fibers, protein and carbohydrates contents of wheat (Table 6).Maximum fibers contents (6.8%) were recorded in MCPA treated plots followed by Isoproturon and Affinity having 5.9% and 5.7% fibers contents respectively.Minimum fibers contents of 2.7% and 3.1% were found in weedy check and hand weeding plots.This increase in the fibers contents of wheat is attributed due to the effective weed control by herbicides and availability of recourses to wheat crop as compared to control plots.

Proteins contents
Data revealed that maximum proteins contents (15.28%) were recorded in Isoproturon treated plots.All other herbicides like MCPA, Bromoxynil, Affinity and Clodinafop have a comparable effect on wheat crop for proteins contents.i.e. (14.81%), (14.34%), (14.19%), (14.03%) and (2.42%) respectively.Minimum protein contents (13.25%) were recorded in hand weeding plot followed by weedy check with protein contents (13.88%).The high proteins in herbicides treatments may attribute to plots to the effective weed control and the availability of resources in order to increases proteins contents in wheat crop.

Carbohydrates contents
Maximum carbohydrates contents (71.81%) were recorded in hand weeding followed by weedy check with carbohydrates contents (71.52%).Among the herbicides treated plots, maximum carbohydrates contents (69.78%) were found in Bromoxynil treated plots while minimum carbohydrates contents (69.68 %) were recorded in MCPA treated plots.Other treatments like Affinity, Clodinafop and Isoproturon have comparable effect for carbohydrates values i.e. 67.31%, 67.10% and 65.92% respectively.The reason for the low carbohydrate content in herbicides treated plots may be attributed to the controlling weeds in these plots, Herbicides also influence the amount of carbohydrate in wheat crop.

Soil analysis
After harvesting the crop, soil from different herbicides treated plots were collected and analyzed for soil texture, soil pH, soil electrical conductivity, soil organic matter and soil nitrogen contents.

Soil texture
Analysis of the data (Table 5) showed that the texture of the soil in all treatments is clay-loam.

Soil pH
Analysis of the data revealed that there is no difference in the pH value in different soil sample (Table 5).The value of pH for different soil samples ranged from 7.7 to 7.8 which are slightly alkaline in nature.

Soil electrical conductivity (E.C.)
Analysis showed that E.C value for different soil samples is variable.Maximum E.C value 0.70 was found in Bromoxynil treated plots closely followed by Affinity with E.C value 0.69.E.C value for control plots was 0.65 (Table 5).It was concluded that these values of E.C favoured the growth of the crops when E.C value is in between 0-2 ds/m 2 .4. Soil organic matter Soil organic matter is also an important factor for the growth of crops.Analysis of the data showed that in different treatments values for the organic matter ranges from 0.54% to 0.73%.Maximum values 0.73% were recorded for control plot and minimum values (0.54%) were recorded for Affinity [6].Wheat ranks 1 st in all cereal crops and annually it occupies 66% area in Pakistan.Through the world, Pakistan has a position among the top ten wheat producing country [3].Sowing time, education, fertilizers application, seed rate, irrigation and herbicides cost are the factors that affecting wheat production [7].The major causes for the low production of wheat in Pakistan are the ignoring of recommended use of technology shortage of water, infestation of weeds, disease etc. [8].Weed infestation is one of the main reasons for the low production [9].It was reported that (18-30%) lose in wheat crop occur due to weed infestation [10].The competition of weeds with wheat crop result in yield reduction [11].Methods for controlling weeds at different growth stages of wheat and weeds are very important [9].
herbicides treated plots, maximum grain yield (2.42kg/m²) was obtained in Clodinafop treated plot and minimum grain yield (1.06kg/m²) in Affinity treated plot.All the other treatments have comparable effect for grain yield.Hassan [29], Khan [30], Abbas [23] and Sangi [10] stated that herbicides treatments significantly increased grain yield in wheat.Controlling of weed at 2-5 leaf stage of wheat, produced maximum grain yield [9].

Figure 2 .
Figure 2. Effect of different herbicides on different parameters of wheat

Figure 3 .
Figure 3.Effect of different herbicides on proximate components of wheat

Table 1 . Herbicides and other methods used in the experiment
Sum of mid-point of coverage classes of species/Total no. of quadrates Relative values were calculated according to the following formulas.

Table 4 . Leaf width (cm), stem width (cm), grains/spike, 1000-grain weight (g) and grain yield (kg m -2 ) as affected by weed management methods at maturation of wheat
Leaf width, 8. Stem width, 9. Grains/spike, 10. 1000-grain weight, 11.Grain yield.Means followed by different letters in the respective column are significantly different at 5% probability level according to LSD test S. No.Keys: 7.