**1. Introduction**

Plants comprise the source of life on earth. In total, 90% of the energy and 80% of the protein consumed by humans are of plant origin. The remaining energy and protein requirements are met by animal products. Thousands of people die every year in many parts of the world due to hunger and malnutrition. It is necessary to increase crop production so that human beings can feed on a sufficient and balanced diet to sustain their existence on Earth. This can only be achieved by increasing the amount of yield obtained from each unit area of land, since it is not possible to further increase existing cultivating areas.

not possible to increase the crop production by using more chemical fertilizers and pesticides

The Effect of Leaf Removal–Based Physical Injury on High Seed and Crude Oil Yields…

http://dx.doi.org/10.5772/intechopen.71357

9

On the one hand, the world population is increasing day by day, and on the other hand, the limits of agricultural land have been reached; it is clear that yield increases still need to con-

Two types of sunflower are grown in Turkey and the rest of the world for oil production and for producing snacks. The production of sunflower oil in Turkey is mostly concentrated in the Trakya-Marmara region, while the production of sunflowers for snacks is mostly carried out in the Central and Eastern Anatolia regions. Oil-type sunflowers are generally black colored, thin-crusted, with 38 to 50% oil and 20% protein in their seeds. Sunflower oil has one of the highest nutritional values among vegetable oils because it contains a high percentage of poly-

Highly efficient genotypes are used to increase the yield in a unit area of land. Chemical fertilization is carried out, and chemical treatments are applied to combat the diseases and pests that cause yield losses in large quantities. However, it is possible to increase the production to a certain degree by using high-yielding cultivars, fertilizing and applying chemicals where necessary. Development of new plant cultivars resistant to biotic and abiotic stress factors by using plant breeding (classical and modern) methods is a difficult task, because the resistance to these stress factors is caused by more than one gene (additive gene effect). Therefore, the development of environmentally friendly new methods to enhance crop production is

In plants, the leaves form the active surface for photosynthesis. The high level of photosynthetic activity also increases the production of substances [3, 4]. In our greenhouse trials, it was observed that defoliation, to a certain level, increased metabolic activity and photosynthetic activity. In sunflower, "star-shaped head stage" is the beginning of the flowering and fertilization period (the reproductive period) followed by the formation of seeds. After this cycle, substances formed as a result of photosynthesis are stored in the seeds. High levels of photosynthetic activity in this stage will increase the production of the material in the leaves and will increase important agricultural characteristics such as seed yield, crude pro-

In the study conducted by Taher et al. [5], seed yield and crude oil yield have been increased significantly by defoliation of the leaves forming the surface for photosynthesis. By the use of the production method described in this study, the amount of crude oil needed in Turkey has been reduced and the large amount of money currently paid for imports was decreased significantly.

The study conducted by Taher et al. [5] was carried out in the research fields of the Faculty of Agriculture, Ankara University in the years of 2013 and 2014. Oil-type sunflower cultivars

unsaturated fatty acids and a low proportion of saturated fatty acids.

in the future.

tinue into the future [2].

extremely important.

tein yield, and crude oil yield.

**2. Materials and method**

It is estimated that world population will increase by 1.5% per year to 8 billion in 2020 and 11 billion in 2050 [1]. The area of land covering the Earth is 14 billion hectares. Currently, 10% of this land area is cultivated. About 20% of the world's land is covered with pastures, 20% with mountains, 20% with glaciers, and 20% with deserts. The remaining 10% of the area has a very shallow soil cover. Given the impossibility of agricultural activities in mountains and glacier-covered areas, there are areas of potential agriculture, such as marshlands, deserts, or areas with insufficient land cover. It is largely impossible to use pastures that cover rugged and very sloping areas as cultivating fields. The conversion of deserts and inadequate land cover into agricultural land requires great investment.

In parallel with increasing population, agricultural areas are being used for other nonagricultural purposes (settlement, road, factory, etc.) or are shrinking rapidly due to erosion, salinization, acidification, intensive agriculture, and overgrazing. It is estimated that agricultural land per capita, which is now 0.26 hectares, will decrease to 0.15 hectares by 2050. In addition, the availability of water resources for modern agriculture will become difficult due to increased water consumption and increasing water pollution [1]. It is expected that food requirements in the most populous parts of the world will double by 2025 [1].

The yield in agricultural production declines due to biotic and abiotic stress factors. Developing a resistant or tolerant cultivar against these stress factors is the main goal of plant breeding. Chemical methods are commonly used to combat biotic stressors (diseases and pests) that reduce crop production. However, the use of chemicals in agriculture causes an extra financial burden and pollutes the environment. In Turkey, 2.3 million tons of chemical fertilizer and 25,000 tons of pesticides (insecticides, fungicides, and herbicides) were used according to the data from 2013. In the last 25 years, it has emerged that the unconscious use of fertilizers and chemicals applied in plant production has negatively affected long-term ecological balance. For example, it has been determined that overused nitrogen fertilizers are washed from the soil and pollute drinking water and the seas, while the nitrogen components that are escaping from the gaseous state are adversely affecting the ozone layer, which protects the earth from harmful rays of the sun. In addition, herbicides and insecticides applied to combat weeds and pests have been shown to destroy the natural equilibrium in agricultural areas, causing the emergences of new diseases and pesticides. It has also been understood that certain chemicals, which have permanent effects, accumulate in plants, and this negatively affects the health of people and animals fed on those plants. As a result, it is not possible to increase the crop production by using more chemical fertilizers and pesticides in the future.

On the one hand, the world population is increasing day by day, and on the other hand, the limits of agricultural land have been reached; it is clear that yield increases still need to continue into the future [2].

Two types of sunflower are grown in Turkey and the rest of the world for oil production and for producing snacks. The production of sunflower oil in Turkey is mostly concentrated in the Trakya-Marmara region, while the production of sunflowers for snacks is mostly carried out in the Central and Eastern Anatolia regions. Oil-type sunflowers are generally black colored, thin-crusted, with 38 to 50% oil and 20% protein in their seeds. Sunflower oil has one of the highest nutritional values among vegetable oils because it contains a high percentage of polyunsaturated fatty acids and a low proportion of saturated fatty acids.

Highly efficient genotypes are used to increase the yield in a unit area of land. Chemical fertilization is carried out, and chemical treatments are applied to combat the diseases and pests that cause yield losses in large quantities. However, it is possible to increase the production to a certain degree by using high-yielding cultivars, fertilizing and applying chemicals where necessary. Development of new plant cultivars resistant to biotic and abiotic stress factors by using plant breeding (classical and modern) methods is a difficult task, because the resistance to these stress factors is caused by more than one gene (additive gene effect). Therefore, the development of environmentally friendly new methods to enhance crop production is extremely important.

In plants, the leaves form the active surface for photosynthesis. The high level of photosynthetic activity also increases the production of substances [3, 4]. In our greenhouse trials, it was observed that defoliation, to a certain level, increased metabolic activity and photosynthetic activity. In sunflower, "star-shaped head stage" is the beginning of the flowering and fertilization period (the reproductive period) followed by the formation of seeds. After this cycle, substances formed as a result of photosynthesis are stored in the seeds. High levels of photosynthetic activity in this stage will increase the production of the material in the leaves and will increase important agricultural characteristics such as seed yield, crude protein yield, and crude oil yield.

In the study conducted by Taher et al. [5], seed yield and crude oil yield have been increased significantly by defoliation of the leaves forming the surface for photosynthesis. By the use of the production method described in this study, the amount of crude oil needed in Turkey has been reduced and the large amount of money currently paid for imports was decreased significantly.
