1. Introduction
Of the 422 thousand flowering plant taxa globally, approximately 72 thousand are utilized and five thousand are subject to trade globally [
1]. Turkey is host to nine thousand plant species, of which approximately 500 are used for drugs or fragrance production, as a country located at the intersection of Mediterranean, European, and Iran–Turan gene centers.
Cultivation of medicinal and aromatic plants dates back to prehistoric times [
2] as an antiseptic and for other therapeutic properties [
3,
4], as well as taste and aroma sources for foods [
5]. An important ancient medicinal and aromatic plant in the traditional medicine and spice industry is fenugreek in Turkey. Fenugreek seeds are consumed as a spice, and all plant parts are used as animal feed [
6,
7]. Its seeds are rich in vitamins, minerals, and proteins [
8,
9], and all other plant parts are also rich in antioxidants, saponins, alkaloids, phenolic acids, flavonoids, phytochemicals, and other medicinal metabolites [
10,
11], which employ the whole plant in traditional medicine [
12,
13].
Fenugreek is taxonomically in the Fabales order, Fabaceae (legumes) family, and Trigonella genus. Specie
Trigonella foenum-graecum L. is cultured in Turkey [
9]. A total of 713 tons of fenugreek seeds were produced from 652 hectares of land during 2020 in Turkey [
14]. A significant increase in fenugreek acreage has been observed during the last five years. With sharp aromatic characteristics [
15], fenugreek is extensively used for the production of pastrami (dried meats, tinned) and breakfast sauces in Turkey [
8]. India is one of the world’s leading countries that produces and exports fenugreek [
16]. China, Morocco, and Turkey are also top fenugreek exporting countries [
9].
In the cold climatic conditions of Turkey, fenugreek is produced in the summer periods, but in warm or hot locations, the cultivation period is winter, or sowings start in early spring [
17]. Studies that included different
Trigonella foenum-graecum varieties were conducted in Turkey’s temperate [
18,
19,
20] and cold climatic conditions [
21,
22]. Fenugreek is well adapted to different climatic and edaphic conditions [
23], but agronomic characteristics such as growth requirements, seed yield, and quality vary between genotypes [
24]. Previous literature suggested that genetic and environmental factors greatly influence the medicinal and aromatic plants’ chemical and biological properties [
25,
26]. Studies on yield and quality characteristics are required to determine superior fenugreek genotypes adapted to different ecological conditions. Therefore, this research was conducted to determine some fenugreek genotypes’ yield performance and quality characteristics in Turkey’s semiarid Anatolian climatic conditions.
2. Materials and Methods
2.1. Location and Duration
The study was performed in the Siirt province of Turkey in semiarid Southeastern Anatolia conditions within the 2018–2020 growth seasons (
Figure 1).
2.2. Climatic Conditions
When climatic data for the growth period (November–June) were analyzed, it was observed that the average temperature in the first year (2018–2019 season) was slightly lower than in the second year (2019–2020 season), whereas the total amount of precipitation was higher in the first year. Total precipitation for both years of the study was higher than the long-term average (
Table 1).
The total amount of precipitation in the first three months (November, December, and January) of the second year of the study was nearly half of the first year (376 mm in the first year compared to 198 mm in the second year). In total, between November and June, there was 121 mm less rainfall in the second year compared to the first year of research. According to the soil climate regime of the Newhall simulation model [
28], it was observed that the study site had a thermic soil temperature regime and a xeric (dry xeric in the subgroup) soil moisture regime (
Figure 2).
2.3. Soil Properties
Soil samples from the experimental field were collected from 0 to 20 cm depth and analyzed before trials. The research soils were clay and clay–loam textured, slightly alkaline, salt-free, and poor in organic matter, containing medium (2018–2019) and low (2019–2020) amounts of lime, medium (2018–2019) and high (2019–2020) amounts of available phosphorus, and sufficient available potassium (
Table 2). The experiment fields in the second year were sandy, low in clay, lime-free, and rich in available phosphorus and potassium. Some physical and chemical properties of the soil samples are given in
Table 2.
2.4. Plant Materials
The Berkem variety of fenugreek was registered by the Faculty of Agriculture, Dicle University. The Gürarslan variety was registered by the Faculty of Agriculture, Ankara University. However, the rest of eight genotypes named Adana, Afghanistan, Gaziantep, Irak, Kayseri, Kahramanmaraş, Mardin, and Şanlıurfa sourced from the Faculty of Agriculture, Kahramanmaraş Sütçü İmam University were used as plant materials. The Berkem variety has a medium height, flat pod-shaped, yellowish rectangular seeded plant with a scarce plumy erect/habitus and white flowers [
29]. The Gürarslan variety has a 50–60 cm plant height, a seed yield of 1.4–1.6 t/ha, a thousand-seed weight of 16–21 g, a dark yellow coated seed, and a pod length of 8–10 cm, and is a pale yellow-flowered and dark green leaf colored plant. Under optimal conditions, it produces 15–20 pods per plant and 8–12 seeds per pod [
30].
2.5. Experimentation
The previous crop to fenugreek in the rotation of the experimental field was wheat. After harvesting the previous crop, trial fields were deeply machine plowed, then prepared with a disc harrow and harrow. Field trials were performed with four replications based on a randomized complete block design. Inter row spacing for four rows in each plot was 30 cm. The plot area was 1.2 m × 4 m= 4.8 m2. The distance between plots–plots and blocks–blocks was 1 m.
Considering soil analysis (
Table 2), 90 kg ha
−1 pure P
2O
5 as triple superphosphate fertilizer (43–44% P
2O
5) was applied evenly in each plot during the first season of research. No phosphorus fertilizer was incorporated during the second season due to the sufficiency of available P in the soil. For both years, nitrogen (N) fertilizer of urea (46% N) was applied to the opened rows at planting with an account of 30 kg ha
−1 as the starter fertilizer.
Weed free fields were sown on 06 November 2018 in the first year and on 15 November 2019 in the second year, at a seeding rate of 30 kg ha−1. Mechanical weed control starts from the emergence of seedlings when required until the vegetation period. The experiments were carried out under rainfed conditions without any irrigation. Harvests were accomplished when the pods turned a yellowish-brown color. Around 0.5 m from both ends of the plant rows and both side border rows were cut out before harvesting the middle two rows in each plot. The plot area at/harvest was 1.8 m2. The seed yields obtained from the plots were analyzed by converting them to hectares.
2.6. Data Collection
To determine days to emergence, the number of days was counted from the sowing date until 50% of the plants were visible in the plot. The number of days was counted from sowing date to 50% of plants were flowered, for determination of days to flowering. The number of days was counted from the sowing date until 90% of the seeds (pods) on the plants turned yellowish-brown in the plot to determine the vegetation period. For biological yield determination, all harvested plants in each plot were weighed after harvest. Biological yield was divided into seed yield to calculate the harvest index.
For the assessment of trigonelline in fenugreek seeds, the ground samples were diluted 1:10 with methanol and mixed in a vortex. The mixture was prepared by a rotary shaker at 150 rpm for 12 h before being filtered on Whatman filter paper and prepared for analysis. A high-performance liquid chromatography (HPLC) instrument (Agilent TC-C18) was used for trigonelline analysis. The flow rate was set at1.0 mL/min by the reverse-phase Inertsil ODS-3 (4.6 × 250 mm) column. The mobile phase (95:5, v/v) was adjusted to pH 3.5 with methanol purified water and hydrochloric acid. Measurements were made at 267 nm at a room temperature of 27 °C. Trigonelline analysis was conducted in the first year of the study by combining plots of the same genotypes. Therefore, trigonelline ratio values were not subjected to variance analysis.
2.7. Statistical Analysis
The data obtained from the research were subjected to the homogeneity test. The data were found to be homogeneous. Combined variance analysis was performed according to the Randomized Complete Blocks design on two-year data. Based on the F test results, the differences between the groups were determined by the Tukey multiple comparison test [
31].
4. Conclusions
Fenugreek genotypes were obtained from different local and international locations; Yield and quality characteristics in semiarid climatic conditions in terms of the year, soil, and climate showed different responses. As a result of the research, a few genotypes were determined to be close to Turkey’s registered Berkem variety in terms of yield and quality. Especially from the Mardin, Kayseri, and Adana genotypes, yields close to the Berkem variety were obtained. While the Gaziantep genotype stands out in trigonelline content, the highest fatty oil content was found in the Afghanistan genotype. When all these results are evaluated together, it is concluded that Mardin, Kayseri, Adana, Gaziantep, and Afghanistan can be used in breeding studies.