Suitable sowing method is essential for crops establishment, which finally affects crops growth.Wheat (Triticumaestivum L) is one of important cereal crops in the world and it has the widest distributionamong cereal. The crop is mainly grown for its grain, which is consumed as humanfood. Planting methods evaluated by many of research were: Line planting, cross planting, Broadcast planting, single row on ridge, and Double row on single ridge. Significant differences were found among the planting methods for number of grains spike-1, 1000 grain weight, biological yield and grain yield. Broadcasting is a fast method of seeding wheat and usually result lower yields, while drill planting method it requires more time, energy and cost, but showed significant highest grain yield than broadcast method. This review shows that line planting gives better results for grain yield of wheat than broadcast and other planting methods studied.Introduction
Wheat (Triticumaestivum L) is the most broadly grown cereal crop in the world, covering about 237 million hectares annually, accounting for a total of 420 million tonnes (Isitor et al., 1990; Langer and Hill, 1991; Olabanji et al., 2004), and for at least one-fifth of man’s calorie intake (Ohiagu et al., 1987). Wheat is an annual grass growing to between ½ to 1 ¼ meters in height, with a long stalk that terminates in a tightly formed cluster of plump kernels enclosed by a beard ofbristly spikes (Smith, 2010).
The U.S. Department of Agriculture (USDA) estimates Iraq’s 2015 market year (MY2015/16) wheat crop at 3.3 million metric tons (MMT). Production is down 200,000 MT, (5.7 percent) from 2014 which was a record crop. The 5-year average for Iraq wheat production is 2.87 MMT. It is the first important cereal crop of Turkey and now accounts for about 67% of the total cereal production with coverage of 11.3 million hectares (Anonymous, 2012).Wheat is the most important and widely adapted food cereal in Iran and Isfahan province. Bertholdsson, N.O.,(2005) theybelieved that wheat originated in south western Asia from where it spread to other parts of Asia, Europe, Africa and America.
The selection of appropriate sowing methods play an crucial role in the placement of seed at proper depth, which ensure better emergence and subsequent crop growth, sowing methods is determine the crops stand and ultimately economic yield.Trodson etal. (1989)showed that planting method has a significant effect on water, nitrogen and phosphorus economy, energy savings and soil compaction. (Mulay et al., 1991; Hossain and Maniruzzaman, 1992; Sharma, 1992) favored line/row plantingmethod butCollins and Fowler, (1992) they recommended that broadcast sowing because of speedy and timely sowing .A key factor in the highest wheat production is the understanding of early crop establishment. Beside other agronomic factors seed rate and sowing method are major factors which determines the crop vigor and ultimate yield (Korres., et al 2002).
Planting Method and Yield Components of Wheat
In wheat (Triticumaestivum L.) the yield components are the number of spikes per unit area, the number of grains per spike and the weight per grain. From a physiological perspective the number of grains per spike is the result of the number of spikelets and the number of grains produced in each spikelet, often referred to as grain set, each of these components being determined at a different stage in crop development (W.R.SCOTT, 1977).
Although studies on yield components can be criticized on the basis that they tend to be compensatory (Adams &Grafi us 1971), such an analysis does define with more certainty the yield limiting processes in crop growth, In wheat the yield components are determined in overlapping sequence, and although there is considerable range for compensation, the amount of scope for such compensation decreases with on togeny (Rawson &Bremner 1976). The first quantitative study on flower initiation and the development of yield components of New Zeal and wheats was assumed by Langer (1965) and Langer and Khatri (1965). Broadly speaking, these studies showed that for autumn-sown wheat at Lincoln the double-ridge stage was reached in early-mid September with ear emergence taking place among late October and early November depending on cultivar. Thus the number of spikelet per spike was determined by late September and the number of grains per spikelet over the following six weeks, with most of the grain filling occurring in December and early January. Langer and Khatri (1965) also found that rapid stem elongation began in late September, presumably the time when maximum tiller numbers were present (Rawson, 1971; Jewiss 1972), but that a proportion of these tillers died during October, the survivors constituting the bulk of the final spike population.
Effect of planting methods on yield component in wheat studied by many researchers like (KILIÇ, 2015) in South-Eastern Anatolian Region, Turkey, An experiment was conducted as a randomized complete block design with four replications using a split plot treatment arrangement. The result expressed that planting methods had significant effect on yield and yield contributing characters except plant height, thousand grain weight (TGW) and protein content. Also, the mean grain yield in flat planting method was 12 % higher than bed planting method. The objective of this research was to evaluate the effects of different planting methods on grain yield and yield components of wheat.
Previous studies show that different planting methods have varying response under different experimental conditions. Hassan and Hassan (1994) have shown that wheat planted in furrows gives maximum 1000-grain weight, straw yield and grain yield. Drilling in lines and cross planting was found to be the best at Johart, Assam during studies made by Gogoi and Kalita (1995). Shaalan et al. (1977) reported that the plant density, ears m-2, number of grains per ear, 1000-grain weight and grain yield were higher in drill planted wheat than broadcasted wheat. According to silkander and Hussain et al.(2003) in Pakistan a study was conducted in 1998-99 at three sites including(kala shah kaku, Kamokey and Gujanwala),these sites were located in the rice-wheat area of punjab.planting methods included bed formation + drill sowing(BDS),broad casting +bed formation (BCB),broadcasting (BC) and drill sowing(DS),which results in plant emergence was higher in drill sowing methods on comparison with other methods .
Traditional Methods of Seed Sowing
Traditional methods include broadcasting manually, opening furrows by a country plough and dropping seeds by hand and dropping seeds in the furrow through a bamboo/metal funnel attached to a country plough. For sowing in small areas dibbling i.e., making holes or slits by a stick or tool and dropping seeds by hand, is practiced(P. Baladarshini et al., 2017).
The best results in wheat stand establishment and yield are obtained by seeding with a grain drill. A drill ensures good seed-to-soil contact, promotes rapid germination, results in more uniform and optimum stands, reduces winter injury, and increases yields over broadcast seeding and aerial seeding, Drills can be used for conventional tillage, reduced tillage, and no-tillage field conditions, also the wheat seed is broadcast on the soil surface with a fertilizer spreader and incorporated into the soil with light tillage (James Herbek , Lloyd Murdock, 1995). The uneven stands from broadcasting often result in lower yields comparing with drilling. Broadcast seeding is a faster method of seeding and can save time during corn or soybean harvest. The time saved may offset some of the greater costs and potential yield loss associated with broadcast wheat (James Herbek , Lloyd Murdock, 1995).
Materials and Methods
Several studies have been conductedto evaluate the effect of different planting methods on grain yield and yield components of wheat .one of them the experiment was conducted at agricultural Research Farm NWFP agricultural university Peshawar during 2004-05, byAttaullah Khan et al. it was laid out in randomized complete block design with four replications, using plot size of 3 x 4.5 m. All recommended agronomic practices were uniformly applied to all of the experimental units.
Wheat cultivar Fakhr-e-sarhad was planted, at the rate of 100 Kg ha-1 seed rate, using following planting methods for evaluation:
I. Line planting ; planting in line with 20cm row to row distance
II. Cross planting: planting in lines from west to east and then from north to south in the same plot to be perpendicular to the first one.
III. Broadcast planting: planting the seeds as broadcast.
IV. Single row on ridge: planting single row on ridge.
V. Double row on single ridge: planting double rows on both sides of the ridge.
The data were statistically analyzed using analysis of variance appropriate for Randomized Complete Block design. Means were compared using LSD test at 0.05 level of probability when the F-value was significant (Steel and Torrie, 1984).
Umed et al (2009) conducted field experiment at PCSIR laboratories, Quetta during the winter season 2005-2006. The experiment was laid out in Randomized Complete Block Design having four replications with net plot size of 6×2 m (Amanullah.,et al 2001).They sowing by these Methods 🙁 Drilling _ Broad casting_ Broad casting in standing water).and then selected 100 plant randomly from each treatment, and they record( plant height, number of tillers per plant, number of spikes per plant , number of grains per spike, 1000-grain weight, grain and straw weight per plot).
Results and Discussion
From Attaullah Khan et al. experiment revealed that planting methods significantly affected number of spikes m-2. Maximum number of spikes m-2 was produced by seed planted in 30cm apart lines followed by double row on ridge, while minimum number of spike was produced by broadcast method of planting. These results are in agreement with Shaalan et al. (1977) who reported more number of spikes m-2 for drill planted wheat than broadcasted wheat.
Attaullah Khan et al. observed that number of grains spike-1 was not significantly affected by different planting methods. However, maximum number of grains spike-1 was recorded in line planted 30 cm apart followed by line planted 20 cm apart and double row on ridge ,while minimum number of grains were recorded in cross planted and single row on bridge . These results are in agreement with Shaalanet al. (1977) and Tanveeret al. (2003), who reported more number of grains spike-1 for improved planting method as compared to broadcasting. This may be due to the effect of planting method on water, nitrogen and phosphorus economy, energy savings and soil compaction (Trodsonet al, 1989).
Higher thousand grain weights was recorded in line planted 30cm apart followed by crossplanted, while lower thousand grains was recorded for broadcast planting method.Attaullah Khan et al. results are in line with previous results of Hassan and Hassan (1994) and Tanveeretal. (2003) who reported smaller 1000-grains weight for broadcast planted wheat as compared to wheat planted with other planting methods.
Maximum grain yield was produced by line planted 30 cm followed by single row on ridge, whereas minimum grain yield was produced by broadcast planted wheat. Hassan and Hassan (1994) and tanveeret al. (2003) have also reported significant difference in grain yield for various planting methods. These results are in agreement with previous results of Mishra and Tiwari, 1999, who reported maximum yield for line planting than broadcasting. Wheat planted by drilling method resulted in taller plants up to 101.95 cm followed by seed broadcasting 97.49 cm and seed broadcasting in standing water 95.17 cm. It may be due to the plant competition as broad casting left uneven space where as drilling provided even space. These results are in agreement with the results reported by (Hattab., et al 1970).
Yield component had significantly influenced bycultivars Line planting (30 cm) showed significant highest grain yield of wheat followed by line planted 20 cm apart and double row on ridge, while drill sowing showed significant highest grain yield than broadcast method, whereas broadcast planted wheat showed lowest grain yield in wheat. Line sowing is recommended for getting higher grain yields of wheat. Biological yield was significantly higher in flat planted wheat (broadcasted and drill sowing) in contrast with bed planting wheat. Maximum number of grains spike-1 was noted in double row on ridge, while minimum numbers of grains were recorded in cross planted and single row on bridge. Drill planting method it requires more time and energy and cost than broadcasting but it showed significant highest grain yield than broadcasting method although broadcasting is a fast method of seeding wheat and usually result lower yields.so, lowgrain yield could be occurred due to the inappropriate planting method and crop management.