Effect of Different Levels of Organic and Phosphate Fertilizers on Yield and Quality of Three Sunflower Genotypes (Helianthus annus L.) in Northern Iraq

A field experiment was carried out in the semiarid region of Talkif district, which is 35 km north of city of Mosul within Nineveh Governorate, during two growing seasons 2019-2020 and 2020-2021 in sandy loom soil to study effect of three levels of organic manure (0, 400 and 800 kg.ha-1), a form of sheep manure, mixed thoroughly with the soil before planting, and three levels of phosphate fertilizers (0, 75, 150 kg ha-1 P2O5) added at once during soil preparation on yield and quality of three sunflower genotypes (Isera, Melabour and Velko). The experiment was carried out using a multifactorial randomized complete block design with three replicates for each experiment. Results indicate: effect of organic fertilizer was significant on all studied traits for both seasons. The treatment by adding organic fertilizer to soil with the amount of 800 kg.ha-1 gave the highest rate compared to addition of lowest ratio (400 kg.ha-1) and comparison treatment. Since Iraqi soil is poor in its content of phosphorus, which ranks second among the three most beneficial elements for plants, the addition of this element to soil at a rate of 150 kg.ha-1 led to a significant increase in all growth, yield and quality traits for both growing seasons. The genotypes of sunflower crop were significantly affected in all growth, yield and quality traits for both planting seasons. The Melabour genotype surpassed Velko and Isera genotypes in the studied traits for both growing seasons.


Introduction
Sunflower (Helianthus annuus L.) is one of the oil crops with great importance in Iraq, Arab world and the globe, as it can be cultivated in various environmental and climatic conditions.It is considered one of the four major oil crops with the highest index of expansion in the world due to its important agricultural characteristics.Sunflower seeds contain a high concentration of unsaturated fatty acids, as the oil contains a high percentage of linoleic acid (50-60%), which reduces Cholesterol content, the seeds also contain 20% protein, and nowadays sunflower oil can be used as a fuel, Moreover, the green leaves of sunflower can be used to feed animals due to its high protein content [1,2].It is used in most industries such as the manufacture of vegetable oils, vegetable butter, baking products, cosmetics, dyes, soap and other industries.The selection of the most suitable genotypes adapted to conditions of the region is a basic technique required to increase productivity and reduce cost of production, so it was observed that the sunflower crop accumulates large amounts of nutrients in its 1259 (2023) 012044 IOP Publishing doi:10.1088/1755-1315/1259/1/012044 2 seeds [3,4].Organic fertilizers are environmentally friendly, as they improve chemical properties, such as permeability, aeration, aggregation, water holding capacity, ion transport and availability by buffering the pH and reducing the absorption of some toxic elements and play a direct role in plant growth as a source of plant nutrients in available forms [5][6][7].The addition of organic fertilizers to soil increases the content of organic matter and leads to the improvement of the physical properties of soil, and at the end it increases the total yield of sunflower crop [8].Phosphorus is one of the essential elements for the growth and productivity of the sunflower crop.It is found in low concentrations in soil solution [4,9].The lack of phosphorous in plants, especially in the vegetative growth stage, leads to delay in flowering, lack of seed filling, and finally low yield and low oil content of seeds [10,11].A study conducted in northern Iraq to determine the response of three sunflower genotypes to phosphate fertilization in sandy soil, [12] noted that adding phosphate fertilizer at a concentration of 100 kg.ha-1 gave the highest rate of both seed yield and oil percentage.Note that the readiness of this element is greatly affected by the quantity in the soil, soil type, climatic conditions, differences in added concentrations and the solubility of the phosphate used [13].The use of chemical fertilizers, especially phosphates, increases seed yield [14].The aim of this research was to evaluate the productivity performance of three sunflower genotypes for different levels of organic and phosphate fertilizers in conditions of the semi rain region of northern Iraq.

Materials and Methods
A field experiment was conducted in the district of Talkif, which is 35 km north of city of Mosul within Nineveh Governorate, during two growing seasons 2019-2020 and 2020-2021 in sandy loom soil in conditions of semiarid region of northern Iraq to study effect of three levels of organic manure (0, 400 and 800 kg.ha -1 ), added as form of sheep manure and mixed thoroughly with the soil before planting.and three levels of phosphate fertilizers (0, 75, 150 kg ha -1 P 2 O 5 ) were added at once during soil preparation on yield and quality of three sunflower genotypes (Isera, Melabour and Velko), planted on 4/5/2019 for the first agricultural season and on 4/8/2020 for the second agricultural season.Nitrogen fertilizer was added in each experiment in the form of urea (46% N) on two batches, half the amount at planting and the second half a month after planting.As for the potassium fertilizer, it was added at a rate of 40 kg.ha -1 in the form of potassium sulfate (48% K 2 O) was added when planting.The experiment was carried out in both seasons using a multifactorial randomized complete block design with three replications for each experiment [15].Duncan's multiple range test was also performed under the 5% probability level [16,17].The experimental unit consisted of four lines, length of the line was 4 m and the area of the experimental unit was 12 m 2 , the distance between the lines was 75 cm and the distance between the plants was 35 cm to give a plant density of 38.095 plants.hectare - .Weed control was done manually twice during two growing seasons by hand hoeing.The experiment was harvested on 12/8 and 7/8 for the first and second agricultural seasons, respectively.Ten plants were randomly selected from the two middle lines of each treatment and the following traits were studied: plant height, stem diameter, number of leaves per plant, flower disc diameter, number of seeds per disc, thousand seed weight, seed yield per plant, total seed yield, percentage of oil and protein in seeds, oil yield and protein yield.Different field soil samples were taken at a depth of (0-30) cm, physical and chemical traits were analyzed according to the method of [18][19][20][21], as shown in table (1). ) for both growing seasons, respectively.The reason for increase in all growth and yield traits may be attributed to effect of organic matter on plant growth through increasing permeability of cellular membranes, stimulating enzymatic reactions, increasing cell divisions, elongating cells, and increasing production of plant enzymes and vitamins inside cells.This finding is consistent with what was found by [6][7][8].

Effect of Phosphorus Fertilizer Levels
Results presented in tables (2-5) confirm that growth, yield and quality traits were significantly affected by levels of phosphorus fertilizer in both seasons.Increasing the addition of phosphorous from zero to 150 kg.ha ) and protein yield (1.22, 1.00 ton.ha -1 ) in both seasons respectively, as the sunflower crop requires a high amount of phosphorus addition, especially in soils poor in its content of this element, as phosphorus enters into the synthesis of nucleic acids, and plays a major role in many reactions Enzymes, it is included in synthesis of all nucleic acids, such as: (DNA, RNA, t.RNA and ribosomal RNA) in addition to being part in synthesis of enzymes necessary for various energy reactions in the processes of respiration and photosynthesis [4].It is also included in composition of phosphorus compounds with bonds rich in energy (ADP and ATP) and in coenzymes, NADP, NAD, and in synthesis of some fats (phospholipids).For living organisms, the importance of ADP and ATP in energy transfer is selfexplanatory [9].As for the enzyme coenzymes NADP and NAD, they have an important role in oxidation-reduction reactions, and depend on them in important vital reactions in photosynthesis, respiration, glycolysis, and in representation of fatty acids and others.Phospholipids are believed to form, along with protein, an important part of cell membranes.Result of current research is consistent with what was found by [10,11and 13].

Effect of Sunflower Genotypes
The results of tables (2-5) confirm that genotypes of sunflower crop were significantly affected in all growth, yield and quality traits for both planting seasons.) and protein yield (1.34, 1.07 ton.ha -1 ) in both seasons, respectively, the differences between genotypes of sunflower crop can be attributed to their differences in the traits of all growth traits that reflect differences in crop components such as number and weight of head as well as weight of 1000 seeds, an increase seed yield per plant as well as per unit area.The result of current research agrees with what was found by [22][23][24][25][26][27][28][29][30].The mean values with in column followed by different letters are significantly at 0.05 and 0.01 level.

Interaction Effects
Results of current research indicate that interaction between organic and phosphate fertilizers was significant only in traits of number of seeds of flowering disc for the first season only, seed yield per plant and total seed yield for the second season only, and oil and protein yield in both seasons.Interaction between organic fertilizer and genotypes was significant only for plant height, protein percentage in seeds for the first season only, oil yield and protein yield in both seasons, while there was no interaction between phosphate fertilizer and genotypes, as well as interaction among three research factors (organic fertilizer, phosphate and genotypes) i.e. significant effect (tables 6 and 7), which indicates that three factors had an independent behavior in their effect on all studied traits.Table 6.Analysis of variance for growth and yield components in two growing seasons.

Conclusion
Organic fertilizer added at 800 kg.ha -1 had the highest rate compared to 400 kg.ha -1 and comparator treatments.Phosphorus, the second most beneficial element for plants, is lacking in Iraqi soil, so adding 150 kg.ha -1 increased growth, yield, and quality for both growing seasons.Sunflower genotypes affected growth, yield, and quality in both planting seasons.Melabour outperformed Velko and Isera in both growing seasons.

Table 2 .
Effect of organic, phosphorus fertilizer levels, genotypes and their interactions on growth and yield components in 2019-2020 growing season.

Table 3 .
Effect of organic, phosphorus fertilizer levels, genotypes and their interactions on growth and yield components in 2020-2021growing season.

Table 4 .
Effect of organic, phosphorus fertilizer levels, genotypes and their interactions on yield and quality in 2019-2020 growing season.The mean values with in column followed by different letters are significantly at 0.05 and 0.01 level.

Table 5 .
Effect of organic, phosphorus fertilizer levels, genotypes and their interactions on yield and quality in 2020-2021 growing season.

Table 7 .
Analysis of variance for yield and quality in two growing seasons.