The Effect of a Number of Irrigations on the Growth and Yield Traits of Three Varieties of Bread Wheat (Triticum aestivium L.)

A field experiment was carried out in Baghdad governorate / Tarmiya district during the Agricultural Season 2018-2019 to study the effect of a number of Irrigations on some growth and yield Traits of three varieties of bread wheat (Triticum aestivium L.), Where Three levels of Irrigation were used (Three, Five, and Eight Irrigations). And three varieties of wheat are (Iraq, Adana 99 and Ibaa 99). The experiment was designed according to the (R.C.B.D) Randomized Complete Block Design with a Split-Plot system and with Three Replications, and the results showed that the interaction between variety Ibaa 99 and eight irrigations was superior in each of the characteristics of the number of days for the appearance of 75% of the spikes, the flag leaf area, the total number of tillers, the number of grains per spike, the weight of 1000 grains, and biological yield which amounted to Their arithmetic averages were (113.36 days, 47.26 cm2, 395.11 tiller.m2, 29.19 grains.spike-1, 44.01gm and 16700.00kg.ha-1), Respectively. The interaction between the variety Adana 99 excelled with eight Irrigations in the two characteristics of spike length and plant height, whose values were (13.41 cm and 96.12 cm), respectively.


Introduction
Bread wheat (Triticum aestivum L.), which belongs to the Poaceae family (Poaceae), is the mainstay for the cultivation of strategic grain crops in Iraq, as it Ranks first in terms of cultivated area and production ,Its grains are an essential source of energy that a person needs, as it is directly included in his food due to its high nutritional value.Although Iraq is one of the first places for the emergence of wheat due to the availability of factors for the success of its cultivation, its productivity does not achieve self-sufficiency [1] and [2], as the production rate for the year 2021 in the world reached about 722 million tons, while in Iraq the rate reached Production is 4,234 thousand tons, and the cultivated area is estimated at 946.4 thousand hectares [3].In view of the large increase in the population, there is a need for an increase in global production of 1.6% annually to cover the growing needs for this crop [4], which necessitated the search for new ways to increase production and productivity from it through the use of new varieties of the crop and the application of scientific research methods in Its cultivation and production programs [5] and that wheat varieties have an important role in increasing production in quantity and quality in terms of the difference in their genetic factors and their interaction with environmental conditions, thus leading to a difference in the ability to respond to the 2 expression of their performance during the different stages of growth and their impact on the yield.It was found in Many studies showed clear differences in the behavior of varieties in terms of growth and production [6].Irrigation is an important factor in increasing the efficiency of producing wheat varieties that are compatible with limited water.In addition, the climate of Iraq is characterized by drought, high temperatures in summer and cold winters, with limited rainfall.The amount of water needed by the wheat crop varies from one region to another depending on the climatic conditions, and irrigation is a major measure.In improving grain yield and increasing its production in arid and semiarid regions [7] .The decrease in the levels of the Tigris and Euphrates rivers due to the lack of rain, in addition to the excessive watering and the lack of rationing the number of irrigations during the growing season for grain crops, especially this crop of wheat, requires a review of how to optimally exploit them and pay attention to the issue of good management by controlling the number of Irrigations in each season or Determining them for the purpose of increasing grain yield and thus achieving food security and self-sufficiency in grains [8] .As a result of the role that water plays in transferring ready-made elements from the soil to the crop in its various stages of growth, it is necessary to schedule the irrigation process and ration the number of irrigations according to the plant's need, especially in the critical stages of its growth, which depend mainly on the type of crop and the cultivated soil [9] .This study aims to determine the best number of waterings and their reflection in the growth and yield characteristics of three cultivars of bread wheat and to find out the optimal interaction between them.

The First Factor: Three Quantities of Irrigation Water, Including
 Three Irrigations: This process included giving the wheat crop three irrigations only (immediately after planting, the blanket stage, and the flowering stage) in addition to the rain that fell during the planting season. Five Irrigations: This process included giving the wheat crop five irrigations (immediately after planting, when germination, the blanket stage, the milky stage, and the doughy stage) in addition to the rain that fell during the planting season. Eight irrigations: This process included giving the wheat crop eight irrigations (immediately after planting, germination, branching stage, blanket stage, flowering stage, milky stage, doughy stage, and before weaning) in addition to the rain that fell during the planting season.

The Second
Factor: Three Varieties of Bread Wheat, Including (Iraq, Adana 99 and Ibaa 99 ( .

Second: Methods of Work
The experiment was carried out in the province of Baghdad / Al-Tarmiya district by plowing the soil with a disc plow and it was smoothed and leveled.A soil sample was taken from the experimental site at a depth of (0.30 m) before planting, and a factorial experiment was applied with two factors by means of Randomized Complete Block Design (R.C.B.D) with the split plot system.As the varieties worker occupied the main plots and the irrigation worker occupied the secondary plots, and the levels of each factor were distributed to the experimental units Randomly and with three Replications so that each Repetition contained (9) experimental units, the area of the Experimental unit was 2 m 2 (2 m X 1 m) and it was divided into lines of distance between one line and another (20 cm) and between one repeater and another (1 m).The experimental land was fertilized with nitrogen fertilizer in the form of urea (46% N) at a level of (320 kg.h -1 ) in two batches, the first at planting and the second at the branching stage.Phosphate fertilizer was also added in the form of triple superphosphate (48% P) at a level of (100 kg P. h -1 ) in one batch when planting, and the seeds of the cultivars were sown manually in the form of a swarm on (10/11/2018) with a seed quantity of (160 kg.h -1 ).All agricultural operations were carried out to serve the crop, including weeding, thinning, insect control and weeds, according to the crop's needs.Harvesting took place after the plants reached full maturity.The number of days until the appearance of 75% of the spikes was calculated, starting from the date of the first irrigation.

Plant Height (cm(
The measurement was made from the base of the plant at the soil surface to the end of the spike, except for the tip.

The Area of the Flag Paper (cm 2 )
The measurement was made at the end of the spikes expulsion stage, because the paper area reaches its maximum limit at this stage, and it was calculated as in the following equation [10]: Paper area(cm 2 ) = Maximum length (cm) × Maximum width (cm) × 0.95

The Total Number of Tillers (tiller.m -2 (
The number of effective and ineffective tillers was calculated for two median lines with a length of one meter from the stage of full maturity, and its average was taken and multiplied by five to convert it to a square meter, because each square meter contains five (5) lines, and the distance between one line and another is (20 cm(

The Length of the Spike (cm(
The measurement was taken from the bottom of the basal spike to the top of the upper spike, except for the apex.

The Number of Grains. Spike -1
It was calculated as an average of five spikes from each experimental unit, and the spikes were separated manually.

The Weight of 1000 Grains (gm)
( 0111 grains were taken Randomly from the final yield of each experimental unit, then weighed with a sensitive scale to calculate the average grain weight.

Biological Yield (kg.ha -1 )
The biological yield was calculated from the weight of the total dry matter (straw + grain in the harvested area) and was recorded in gm.m -2 , then converted to kg.ha-1 according to the equation [11] .As in the following equation:  , 2002), and the averages of the transactions were compared using the Duncan multi-range test with a probability level (5%), According to this test, the averages followed by similar alphabet letters do not significant differences from each other and followed by different letters, as they differ from each other significant differences [ 01 ] .

The Number of Days for 75% of Spikes to Appear
It is defined as the time period extending from germination until the emergence of more than twothirds of the spike from its cover, with more than more than 75% of the total number of plants formed for one variety in one treatment [ 3. ] , and it is one of the key and important characteristics that must be taken into account when selecting between cultivars as Early harvesting provides an important opportunity to apply the agricultural cycle and efficiently manage agricultural operations during the crop life cycle [14].Table No. (2) Shows the Effect of varieties and the number of Irrigations and the interaction between them in the number of days until the emergence of 75% of the spikes, where the cultivar Iraq was earlier in the aforementioned capacity by recording (99.88 days) and with a significant difference over the other two cultivars.On the contrary, the variety Ibaa 99 was late with a value of (112.44 days).With regard to the number of irrigations, there were no significant differences between their averages.With regard to the interaction between cultivars and the number of irrigations, the earliest interaction between cultivar Iraq with three irrigations was recorded (97.98 days), while the interaction between variety Ibaa 99 and eight irrigations was recorded (113.36 days).Perhaps the reason for this delay is due to the amount of response of the genotype and nature of cultivar Ibaa 99 to temperature and the length of the photoperiod during daylight hours when the appropriate amounts of irrigation and rain are available, and these results are consistent with what was reached by [15].
Table 2. Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the number of days until the appearance of 75% of spikes (day).

Plant Height (cm)
Plant height is one of the important characteristics of growth, and it is affected by the genetic factors of varieties and the surrounding environmental conditions, especially the availability of growth factors such as water, nutrients, and others [16].Table No. (3) Shows the Effect of varieties and the number of Irrigations and the interaction between them in the Trait of plant height (cm) As for the varieties, the variety Adana 99 outperformed by giving it the highest average of (93.66 cm) and a significant superiority over the other two varieties, while the variety Ibaa 99 gave the lowest average of (80.82 cm) with regard to the average number of Irrigations, so there were no significant differences in this trait.With regard to the interaction between the two factors of the study, the interaction between the variety Adana99 with eight irrigations was superior by giving it the highest average of (96.12 cm) and with a significant superiority over all other interactions.Over all other overlaps, this on the one hand and on the other hand, the two overlaps between cultivar Ibaa99 with three irrigations and five irrigations gave the lowest mean (80.01 and 80.44 cm), respectively.Perhaps the reason for this superiority is due to the number of irrigations and their periods suitable for the plant, which were consistent with the genetic makeup of the Adana 99 variety, and the increase in its content of gibberellin and auxin, which are Responsible for the elongation and expansion of cells, which led to an increase in cell division and breadth, in addition to an increase in the growth of meristematic tissues as a result of the availability of nutrients in them, which led to lengthening plant and increasing its height.These results agreed with [17,18].

The Area of the Flag Paper (cm 2 )
The importance of the flag leaf is due to the important role it plays in supplying the grain with nutrients in the last stages of growth, as it contributes 80% of the materials transferred to the grain [19].The results of Table (4) indicate the effect of varieties, the number of irrigations and the interaction between them on the Trait of the flag leaf area (cm 2 ).The variety Ibaa 99 was significantly superior, with the highest mean (45.88 cm 2 ), on the contrary, the variety Iraq recorded the lowest mean (34.61 cm 2 ).As for the average number of irrigations, there were no significant differences.With regard to the interactions, the interaction between the variety Ibaa 99 and eight arrows excelled by recording the highest average of (47.26 cm 2 ) And with a significant superiority over all other interactions, this on the one hand, and on the other hand, the interaction between the variety Adana 99 and three irrigations with the lowest average of (32.88 cm 2 ).The reason may be due to the differences of varieties among themselves in the length of the growth period, which may contribute to the difference in the leafy area.Varieties with a long growth period are given a longer period of time to produce, grow and develop the leafy area in a more efficient way compared to the varieties with a shorter period of growth, and these results agreed with [20][21][22].Table 4. Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the flag leaf area (cm 2 ).

The Total Number of Tillers (tiller.m 2 )
The production of tillers is a desirable characteristic in grain crops, as tillering plays an important role in the productivity of wheat, and its composition depends on the genotype, environmental conditions, and crop service factors [23] .The results of Table (5), which shows the effect of the varieties, the number of irrigation, and the interaction between them in the total number of tillers (tiller.m 2 ).We find the superiority of the variety Ibaa99 by recording the highest average of (392.89tiller.m 2 ), with a significant superiority over the other two varieties, while the variety Iraq gave the lowest value amounting to (298.72 tiller.m 2 ).With regard to irrigation averages, there are no significant differences.We are still in the same table, where the interaction between variety Ibaa99 and eight irrigations was superior, with the highest average (395.11tiller.m 2 ) and with a significant superiority over all other interactions.On the contrary, the interaction between variety Iraq and three irrigations gave the lowest average (297.77tiller.m 2 ).This superiority can be explained by the genetic nature of the cultivated variety and its ability to grow and benefit from the available growth requirements that are transmitted to it through the water available during the irrigations process with irrigation and rain, and this is consistent with [6] and [24] .Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05).

Spike Length (cm)
The spike is the source of the outputs of the photosynthesis process to the grain, through the role of its parts (the spike, the sap, the stem, and the spha) in the process of photosynthesis, as the spike is the source and the downstream at the same time, and it is considered one of the quantitative Traits that are related to the yield [25] .We infer from the results of Table (6).which shows the effect of varieties, the number of irrigation, and the interaction between them in the in the Trait of the spike length (cm).
The variety Adana 99 excelled by registering the highest average of (12.27 cm) and with a significant superiority over the other two varieties of the study, while the variety Iraq gave the lowest average of (8.31 cm).With regard to the average number of irrigations, the number of eight irrigations was superior, with the highest average reaching (11.69 cm), which did not differ significantly with five irrigations, who gave (10.66 cm), but it was significantly superior to the average of three irrigations, who gave the lowest average, which reached (9.44 cm).When observing the results of the interaction in the same table, we find the superiority of the interaction between the variety Adana 99 and eight irrigations, which gave the highest average value of (13.41 cm) and with a significant superiority over all other interactions treatments, On the one hand, on the other hand, the interaction treatment between Iraq and three irrigations recorded the lowest value (7.33 cm).The reason may be due to or the variation in the length of the spikes due to the different genotypes of the varieties and the nature of their growth as well as their competitive ability to obtain the largest amount of light and the elements necessary for growth, and this depends on the genetic ability of growth and competition [17] .Table 6.Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the spike length (cm).Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05) .

The Number of Grains Per Spike (grain. spike -1 )
The Trait of the number of grains per spike is of great importance in determining the total grain yield in grain crops, especially in Stress conditions, and it is the strongest factor related to the grain yield, as this characteristic is one of the quantitative and most important Traits of the yield and one of its main components [26] .When examining the results of the table No. (7), which Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the number of grains per spike (grain.spike -1 ).As for the averages of the varieties, we find a significant superiority of the variety Ibaa99, with the highest average of (27.88 grains.spike -1 ), and superiority over the other two varieties, which gave the lowest average, which amounted to (22.83 and 23.93 grains.spike -1 ), respectively.With regard to the average number of irrigations, we notice a significant superiority for the number of eight irrigations, with a value of (26.53 grains.spike -1 ), and a significant superiority over the averages of the other two irrigations, which recorded the lowest value of (23.45 and 24.65 grains.spike -1 ), respectively.As for the results of the interactions, the interaction between the cultivar Ibaa 99 and eight irrigations gave the highest mean (29.19 grains, spike -1 ), with a significant superiority over all other interactions On the one hand, on the other hand, the interactions between variety Adana 99 and three irrigations recorded the lowest value (21.39 grains.spike -1 ).This superiority can be explained by the availability of the appropriate amount of water needed by the plant during its various stages of growth, especially the critical periods, as it is compatible with the nature of the cultivar Ibaa 99, and thus a balance occurs in filling the grains with spikelets, and these results agreed with what was reached [27,28].Table 7. Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait the number of grains per spike (grain.spike -1 ).

Weight of 1000 Grains (g)
The weight of the grain is one of the important components of the wheat yield and a measure of the amount of materials accumulated in the grain.An increase in the weight of the grain means an increase in the yield and indicates the rate and duration of the grain growth.The variation in the weight of 1000 grains is due to the genetic variation of the cultivated varieties and the environmental factors related to the growth of the crop [29] .The results of Table No. ( 8) Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the weight of 1000 grains (g), where the variety Ibaa 99 excelled by recording the highest arithmetic mean of (41.72 g), which was significantly superior to the two varieties Adana 99 and Iraq, which gave the lowest average with their values ( 32.15 and 33.15 g), respectively.As for the irrigation averages, no significant differences were recorded.When observing the results of the interactions in the same table, we find a significant superiority of the interaction between the variety Ibaa 99 and eight irrigations by recording the highest arithmetic average value of (44.01 g) and a significant difference over all other interactions.On the contrary, the interaction treatment between the variety Adana 99 and three irrigations of the gave the lowest average with value of (29.61 g).My account amounted to (29.61 grams).The reason may be due to the different wheat varieties included in the study in the weight of 1000 grains, to the difference in the characteristics of the other components of the crop, the size of the vegetative system, and to the availability of appropriate and sufficient quantities of water that transport the nutrients necessary for the fullness of the grain from the source (soil) through the roots and stem to the downstream (grain).and accumulate in them and increase the chance of filling them and reduce competition among them, and these results were in line with what was reached [6] and [30] .Table 8.Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait on the weight of 1000 grains (g).

Biological Yield (kg.h -1 )
It is defined as the net product of the process of photosynthesis and the absorption of nutrients, and the biological yield represents a measure of the total dry matter produced by the plant from all its parts above the soil surface during the various stages of growth., thus includes the grain yield, in addition to the straw yield, which results from the difference between the photosynthesis and breathing processes.The two processes are largely influenced by several environmental and genetic factors [31] .When observing the results of Table No. ( 9), Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the biological yield (kg.h -1 ).As for the averages of the varieties, the variety Ibaa99 excelled by recording the highest arithmetic average of (16386.10kg .h - ) with a significant superiority over the other two varieties, while the variety Iraq recorded the lowest average of (11403.00kg .h - ).With regard to the average number of irrigations, there were no significant differences between them.We are still in the same table.The interaction between the variety Ibaa99 and eight irrigations gave the highest arithmetic mean of (16700.00kg.h -1 ) and with a significant superiority over all other interactions.On the contrary, the interaction between Iraq and three irrigations lower accounts were given (11019.00kg.h -1 ).. The reason may be due to the nature of the genetic makeup of the cultivar Ibaa 99, which excels in the characteristics of each of the spikes, table (2), flag leaf area, table (4), total number of tillers, table (5), the number of grains per spike, table (7), and the weight of 1000 grains, table (8).These results are consistent with [32] and [33].Table 9. Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the biological yield (kg.h -1 ).

Conclusion
We conclude from the study that I conducted that the best combination of interactions in most of the studied traits of bread wheat was between the Ibaa 99 and Eight Irrigations.

Table 1 .
Some Physical and Chemical properties of Soil and Irrigation Water.
Statistical AnalysisStatistical analysis of all results was carried out on the basis of variance analysis of the studied traits according to global experiments by Randomized Complete Block Design (R.C.B.D) according to the split plot system in the program (Statistical Analysis System SAS-V9 Biological yield of the experimental unit × 10000) / (Area of the experimental unit ) 1259 (2023) 012102 IOP Publishing doi:10.1088/1755-1315/1259/1/0121024 2.4.

Table 3 .
Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of plant height (cm).Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05) .

Table 5 .
Shows The Effect of Varieties, The number of Irrigations and the interaction between them on the Trait of the total number of tillers (tiller.m 2 ).
Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05).
Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05).
Similar letters indicate that there are no significant differences according to the Duncan multi-range test and below the probability level (0.05).