Climate Change and Global Warming Effect(s) on Wheat Landraces: A General Approach

Abstract

In plant production, the main objective is to increase the unit yield area with related measures. Without taking the suited precautions, yield level cannot increase as much as it is desired, and it is clear that some impacts of climate change (CC) and global warming (GW) may threaten the plant life. Additionally, day by day, these limitations increase. Researches have shown that the emergence of water deficit in one place at any time is called as drought, and this is one of the most important limitations in any plant production. Landraces are also affected by greenhouse gases (GHGs) (namely and mainly CO₂, CH₄, N₂O, water vapor, halocarbons, and chlorofluorocarbons) which are part of climate change. Rice (Oryza sativa) plant, from the same family with wheat (Triticum spp.) plant, has released a greenhouse gas (CH₄), with a share of 94%. On the other hand, available scientific data show that the world temperature will increase annually by an average of (1,4–5,8) °C by the end of 2100, and this can affect many plants, ecology, ecosystem, ecosystem balance, many other ecological/climatic parameters, etc. in different levels. Especially global warming (GW) and climate change (CC) affect plant development, due to the environmental temperature, humidity, plant growth stages, soil characteristics, speed and capacity of the photosynthesis, water use efficiency (WUE), earliness, maturity, harvestability, harvest and tresh, and some agronomic traits such as plant height, 1000-grain weight, tillering capacity, etc. On the other hand, yield and yield components (= which means dry matter yield) can affect the mineral content or productivity level partially or completely depending on soil properties. Where the growth factors such as light, temperature, and humidity are insufficient in the areas where the wheat landraces are grown, the factors associated with various chemical and physiological characteristics are of great importance in the development of mechanisms to minimize the impact of the CC. Considering the phenotypic, physiological traits of the wheat landraces, they should be used as a parent or genitor for the selection(s) or hybridization(s) under the multidisciplinary approach of agronomy, plant breeding, tissue culture techniques, and genetic engineering applications.

9.1 Introduction

The world’s human population is predicted to reach over 12 billion by the year 2050 (Anonymous 2018a) according to UN, and population projection and shifts in diets toward animal products, oils, and other resource-intensive foodstuffs are placing even more pressure on agricultural systems to increase production (Kastner et al. 2012). Changes in temperatures and precipitation are known as climate change (CC). Nevertheless, global warming (GW) is a different phenomenon. Shortly, their impacts depend on their size and frequency/frequencies (Semenov et al. 2014). As known, CC affects many sectors, particularly the agricultural sector (Mengü et al. 2008), with its amount and time (Valizadeh et al. 2014). The main factor, due to the human activity, is an increase in the greenhouse gas concentration (CO₂, CH₄, N₂O, and types of halocarbons (CFC)), and the gases that regulate the climate system and absorb the sun’s light rays (Tubiello et al. 2000).

While climate is important for agricultural production due to its parameters such as temperature, precipitation, humidity, etc., global warming threatens the agricultural production because of GHG accumulation in the atmosphere. Due to GHG accumulation, sunlight is not reflected back to space, thereby increasing the Earth’s temperature (IPCC 2007, 2014). Researcher Fuhrer (2003) reported that global warming would lead to an increase in world temperature by 2100 (1.4–5.8) °C, leading to significant agricultural losses. The amount of losses is related to the increase in CO₂ and CH₄ and other greenhouse gas concentrations in the atmosphere (Zavarzin 2001). The CO₂ gas content was 270 ppm before the Industrial Revolution, reaching up to 355 ppm in the modern age. It is expected to reach 600 ppm in the twenty-first century (Rogers et al. 1994) (Fig. 9.1).

Fig. 9.1

Some greenhouse gas concentrations and global temperature change over the last 2000 years (Di Norcia 2008)

The most recent value of CO₂ gas is 411.97 ppm according to the records in March 2019 (https://www.co2.earth/). Greenhouse gases CH₄ and N₂O have annual growth rates of 1% and 0.3%, respectively. All GHG gases protect the Earth by acting as a shield against harmful rays of the sun and negatively affect O₃ gas in the troposphere (Krupa 1997); they are (GHGs) spreading from the refineries, rice paddies, and various elements such as the atmosphere (Mei et al. 2007) (Fig. 9.2).

Fig. 9.2

The graph of mean global temperature rise in the measured period (Nema et al. 2012)

The effect(s) of CC and GW can be illustrated as follows (Fig. 9.3):

Fig. 9.3

Schematic showing CC and GW effects on wheat landraces (original)

Future climate change scenarios suggest that abiotic stress may occur at unexpected stages of plant development, thus decreasing yield consistency, and various global warming scenarios could reduce wheat productivity in zones where optimal temperature already exists, potentially increasing food insecurity and poverty (Elissavet et al. 2014), and consequently all the landrace’s genotypes, including the wheat, have a very important/crucial/vital place in plant breeding for the elimination of many agricultural deficiencies against abiotic and biotic stresses. However, in predominantly self-pollinated species like wheat, no long-term investments are attractive when farmers use their own seeds (Stamp and Visser 2012). There is an inverse relationship between the ability to compete with yield and adverse conditions in the wheat lands, and they are valuable gene pools due to many other superior properties (such as high protein content) (Lopes et al. 2015) (Fig. 9.4).

Fig. 9.4

Direct, indirect, and socioeconomic effects of climate change on agricultural production (Rosenzweigh and Hillel 1995; Raza et al. 2019)

On the other hand, CC and GW have some both positive and negative effects. All of them can be illustrated as follows (Fig. 9.5):

Fig. 9.5

Overall positive and negative effects of climate change and global warming on crops and humans (Raza et al. 2019)

Climate change refers to changes in climate measures over a long period of time, say approximately 100 years, but global warming is a natural phenomenon that affects all living and nonliving things arising from greenhouse gases. The information obtained in all these processes is very important for the sustainability of the agricultural sector. In fact, the agricultural sector is extremely vital to various inputs (such as biodiversity, soil, water, etc.). However, in any case, CC and its natural consequence, the GW, are the factors that threaten our planet, and the effect is getting felt more and more every day. In another study, it was found that wheat yield decreases by 4.1% to 6.4% in each crop due to global climate change. Consumption is estimated to be more than 30% in 40 years of production (Tricker et al. 2018). As known, all culture plants are classified as C3, C4, and Crassulacean acid metabolism (CAM) according to the number of carbons they bind to the nutrients they form by photosynthesis. C3 plants are trees, edible legumes, rice (Oryza spp.), wheat (Triticum spp.), barley (Hordeum spp.), soybean (Glycine max), potato (Solanum tuberosum), vegetables, citrus (Citrus spp.), grape (Vitis vinifera), coffee (Coffea arabica), tea (Camellia sinensis), peanut (Arachis hypogea), lemon (Citrus limon), peach (Prunus persica), mango (Mangifera indica), carrot (Daucus carota), etc. with a sowing area of 200 million hectares and constitute approximately 21% of the total nutritional requirements in the world (Anonymous 2018a). Such plants are less affected by CC limitations (as compared to C4) due to CO₂ fertilization, but their yields increase as much as 36% (Uzmen 2007; Mercer and Perales 2010), but afterward, they immediately reduce. The situation may even reduce the photosynthetic activity in other C3 plants outside the grain (Zhai and Zhuang 2009). It is concluded that temperature extremes are complementary to the important physiological parameters in wheat landraces. Frost and heat events cause infertility in bread wheat landraces and cut the grain formation, and the excess heat decreases the number of grains and narrows the formation process. CC’s photosynthetic activity with increased photosynthesis rate but increased CO₂ concentration and decreased the WUE values ​​(Dhakhwa and Campbell 1998) was expressed. All the C3 plants, especially local wheat landraces, have different responses to increased CO₂ gas concentration and other climate factors.

Obtained findings showed that elevated CO₂ increases. Findings show that dramatically affect the growth and development of plants against CC and its consequent of GW (Romanova 2005); elevated CO₂ also increases WUE, and is particularly distinct in C3 plants (Cutforth et al. 2007); especially high temperature increasing during the flowering and growing stages decrease grain filling rate, nutrient balance, and all of these adversely affects the fruit and grain formation, especially the critical temperatures at (35–40) ^°C prevent the development of pollen development with the meiosis division (Fuhrer 2009) (Table 9.1).

Table 9.1 Some agronomic and botanic responses to CC and GW of the wheat landraces’ traits. (Modified from Krupa (1997), Dhakhawa and Campbell (1998), Tubiello and Ewert (2002))

The anatomical effects of CC on plants, including wheat landraces, generally result in the increase of the CO₂ concentration and the increase in temperature and their interaction(s). Changes happen in the thickness and viability of leaves as a result of these factors and interaction, decrease in plant height, in growth and development; at the stomata, decrease in the water uptake of the increased amount of chloroplasts in the cell (Romanova 2005; Mei et al. 2007; Ulukan 2008, 2009) (Table 9.2). They rarely fail in the most extremely stressed environments (Ceccarelli 1994) (Figs. 9.6 and 9.7).

Table 9.2 Some agronomic traits which are based physiologically on wheat landraces (Fischer 2001)

Fig. 9.6

Effect of CO₂ fertilization on wheat landraces’ some physiologic components (Lenart et al. 2006)

Fig. 9.7

General impacts of elevated CO₂ on plants (Anonymous 2018b)

9.1.1 Landrace Formation

A landrace of a self-pollinated crop can be defined as a variable population which is identifiable and usually has a local name (Jaradat 2012), and its formation has been carried out for quite a long time with a selection process that is not entirely done by human. During this period, they have survived to the present day by maintaining their resilience to stress factors in their natural conditions, but their yield levels were not as high as modern varieties, but their nutritional values were found to be quite high (Nasserlehaq et al. 2011). On the other hand, they have played a fundamental role in the history of crops worldwide, in crop improvement and agricultural production, and they have been in existence since the origins of agriculture itself (Villa et al. 2006). There are approximately 50,000–60,000 species of crop wild relatives (CWR), of which 10,000 may be considered of high potential value to food security, with 1000 of these being very closely related to the most important food crops (Maxted and Kell 2009; Dempewolf et al. 2014). They have higher biological yields than the cultivated varieties, root dry weights are not very high, but can be increased depending on the situation, transpiration efficiency is higher, soluble carbohydrate concentration is higher than early (early dry matter transfer), early ripening or maturity, grain yields lower (due to earliness) and escape from drought, alternative growing nature, low harvest index, taller and united to low nitrogenous conditions with micronutrients (such as Cu, Fe, Mg, Mn, P, Se, and Zn), especially wheat landraces in the Southeastern Anatolia, the response to fertilizer low, which are not suitable for machine agriculture, sensitive to leaf diseases, adaptation ability is high, grain quality is good, generally coarse grains, stalks and straws are consumed by animals and liked by animals (Jaradat 2012; Özberk et al. 2016).

Essentially, there are two types of landraces according to Jaradat (2013):

• (a) Primary: Developed its unique characteristics through repeated in situ grower selection and never been subjected to formal plant breeding as autochthonous and allochthonous

• (b) Secondary: Developed in the formal plant breeding sector but is now maintained through repeated in situ grower selection and seed saving

Generally, the formation of the landraces can be schematized as follows (Fig. 9.8):

Fig. 9.8

Schematized landrace and modern variety general formation. (Modified Cleveland et al. 1994)

They represent heterogeneous, local adaptations of domesticated species, and thereby provide genetic resources that meet current and new challenges for farming in stressful environments, especially landraces, provide a valuable gene resources for enhancing the crop adaptation to abiotic stresses (Dwivedi et al. 2016), and, landraces have been defined as dynamic populations of a cultivated plant with a historical origin, distinct identity, often genetically diverse and locally adapted and associated with a set of farmers’ practices of seed selection and field management as well as with a knowledge base (Bellon and Etten 2014). These carry beneficial genes that were not introduced into elite durum cultivars (Kabbaj et al. 2017). Northern landraces evolved a higher tillering capacity, fewer grains per spike and less fertile tillering than those from the south. Our results support the hypothesis that during the Neolithic dispersal of durum wheat from the Fertile Crescent to southern Europe, significant and gradual changes in yield component structure of populations occurred (Akçura 2009). The main threat to the landraces (including wheat landraces) is current minor or major industrial developments such as construction of huge shopping malls, housing, apartments and blocks, and golf fields, leading to reduction in biodiversity. The landrace gene pool harbors a wide genetic diversity that could be used to enrich the modern wheat genetic repository (Blum et al. 1989; Dotlačil et al. 2010; Ben-David et al. 2014). Wheat landraces generally tolerant to biotic and abiotic stress have been grown under low-input or sustainable farming conditions where they produce reasonable yield (Akçura 2009).

CC and GW effects on wheat landraces, like other cultivated plants, can be itemized as follows (Gray and Brady 2016; Anonymous 2019):

• 1. Air enriched with CO₂ stimulates growth and development of wheat landraces, thus resulting in the development of more fibrous and voluminous root systems.

• 2. Leaf size increases and cells expand.

• 3. More CO₂ (which means elevated CO₂) means less water stress.

• 4. Helps cope with low levels of essential resources such as light, water, nutrients, etc.

• 5. In less than optimal conditions, higher CO₂ means more plant growth.

• 6. Atmospheric CO₂ enrichment increases plant water acquisition.

• 7. Rising CO₂ enhances plant resource acquisition, such as root system, nitrogen-fixing bacteria, symbiotic soil bacteria, carbon starvation, etc.

• 8. Promotes the growth of important soil fungi such as rhizosphere, mycorrhizae, etc.

• 9. At current CO₂ concentrations (February 2019, which is 411,75 ppm (https://www.co2.earth/), plants are close to starvation.

• 10. Elevated CO₂ level helps plants to survive environmental stresses such as salinity, pollution, elevated temperatures, etc.

• 11. Elevated CO₂ level helps in reducing the negative impacts of soil salinity on plant growth.

• 12. Elevated CO₂ level helps in reducing the negative impacts of high temperatures on plant growth.

• 13. Elevated CO₂ level helps wheat landraces to survive biological stresses such as weeds, diseases, insects, herbivory, etc.

• 14. Rising CO₂ does not disappear with time (but it has been observed that in some plant species, foliar N concentrations may decrease; however, in others, it will not).

• 15. Rising CO₂ enhances carbon sequestration (particularly, this issue is very crucial in terms of the sustainability of agroecosystems, grasslands, and forests).

All the effect(s) of the CC and GW’s components were summarized on wheat landraces’ traits which were presented generally in Tables 9.1 and 9.2.

Increasing the temperature rises evapotranspiration and drops the soil moisture availability and increases the growth and development of plants, including wheat landraces, due to higher CO₂ concentrations. Wheat landraces, based on their nutritional value, when locally produced can contribute to lower greenhouse gas emissions (0.1 g CO₂ per calorie) as compared to rice (0.43 g CO₂ per calorie) or vegetables (0.57 g CO₂ per calorie) (Jaradat 2013). In addition to this information, Schlenker and Roberts (2009), the yield of low CO₂ concentration, the wheat landrace (36%- (-40))% and (63–70)% depending on the statistical program used. Hatfield and Prueger (2011) calculated it as 3.8–5.0%, and Fuhrer (2009) stated that the increase of 1 °C in the temperature caused a decrease of 7.0–124.0% in the yield level. At the same time, it has been reported that wheat yield losses in developing countries (producing 66% of the total wheat production) are likely to be around 20–30% due to the increases in temperature caused by climate change (Easterling et al. 2007; Lobell et al. 2008). Under normal conditions and during the development period, the mean temperature increase of 1 °C, causes 6 kg/ha yield losses in durum and 12 kg/ha common wheats, and it is expected that the number of wheat yield losses will be between 20 and 30% with a temperature increase of 2–3 °C in developing countries until 2050 (Anonymous 2011; Sayılğan 2016). High temperature (air and soil temperature) and water deficit (drought) are the most important environmental factors that limit plant growth in many huge/mega wheat fields of the world and occur simultaneously (Shah and Paulsen 2003). But its mechanism is still unknown.

The main threat caused by CC and GW is not only increased or elevated CO₂ concentration and temperature but also reduction of the effectiveness of RuBisCo during the production of glucose via PSII stage in photosynthesis. In parallel, the WUE value diminishes. This development leads less water for a less dry matter (that means low yield level), the role of the RuBisCo and indirectly WUE value which is very important. But their mechanisms, etc. are still not fully and clearly known today. In any case, the main aim should be an increase in the WUE values of wheat landraces, especially those grown in arid and semiarid regions.

The enzyme RuBisCo has played a crucial and vital role in photosynthesis and one of the most abundant proteins in leaves of plants. Accelerated development and premature senescence were the primary factors affecting its activity in response to the CO₂ enrichment. This role is very clear during photosynthesis and this enzyme is in close relationship with the WUE of the plant, especially during CC and the GW (Table 9.3).

Table 9.3 Main agronomic traits of strategically important 18 major field crops (Rötter and Geijn 1999)

According to Marin and Nassif (2013), the increase of atmospheric CO₂ concentration increases the gradient that drives the diffusion of CO₂ from the atmosphere to the chloroplasts. And this effect stimulates photosynthesis and reduces stomatal conductance, and a reduction in the transpiration rate happens (Taiz and Zaiger 2013). In Tables 9.1 and 9.2, CC and GW act on C3 plants effects have been with their components. Especially their effects on “vernalization, CO₂/O₂ rate, respiratory rate, seed maturation, sub- and topsoil biomass production, number of internodes, weed distribution, germination of seeds, root/stem or rhizome, seed longevity, DNA molecule and sterility, ecological parameters, etc. “ have not yet been fully known. Their effect on the plants is mostly and generally on the biomass, specifically on the leaf and leaf factors. At the selections to be made by taking advantage of the relevant features, which are mentioned or not mentioned in Table 9.2, wheat landraces can be used to complete a gene resource and the missing characters(s) for a valuable genitor or donor.

Water sources and/or soil moisture, which are diminishing due to the decreases in wheat sowing areas and climatic reasons,, have been emphasized that the wheat landraces are an insurance for future agricultural production. Wheat landraces have agriculturally more undesirable traits such as hulledness in grain, tallness, and low yield level(s) than modern commercial (wheat) varieties. However, cultivation of landraces has been successful for many years without any human intervention under stress conditions. The main contributions of wheat landraces to plant breeding programs have been their desirable traits such as having efficient nutrient uptake and utilization and having useful genes adapted to stressful environments such as water stress, salinity, and higher temperatures (Dwivedi et al. 2016).

In the light of the information that was given, our recommendations are (generally) as follows:

• To make national or international agreements that enable effective use of both CO₂ and water resources.

• To minimize the release of CH₄ from ruminants and nitrous oxide by efficient fertilization (Prasad 2009).

• To avoiding excessive and artificial nitrogenous fertilization.

• To take crop rotation and animal feeding of tuberous plants and legumes (Ulukan 2009).

• To use alternative or clean energy sources.

• To apply minimum soil tillage techniques (Çakır et al. 2009).

• To use organic or environmentally friendly agricultural practices.

• To not burn waste materials at the end of the production.

• Especially in continents, coasts, and oceans, to take the necessary measures without forgetting that the polar regions will warm faster than the equator.

• All activities that cause greenhouse gas emissions should be terminated or minimized.

• Without losing the principle of sustainability, to prevent the destruction of soil, water, and biodiversity.

• When they are used as parent(s) directly in the hybridizations, expands high yielded modern wheat cultivars’ and provides the resistance to biotic and abiotic stress factors; in addition, the use of bridge hybridization (Şehirali and Özgen 1987), the production of seeds on a periodically, scientifically and characterization is of great importance (Özberk et al. 2016).

• To develop new (wheat) varieties which are also suitable for the purpose of producing wheat landrace, especially from the elements of genetic variation (Heslop-Harrison 2012). It should be used as rootstock or genitor in breeding studies by utilizing physiological characteristics.

• The development of new varieties using wheat landraces that are more adapted to local biotic and abiotic stresses presents a viable strategy to improve and sustain yields, especially under stresses and future changes in climate (according to Calanca (2017).

• However, landraces with high genetic diversity should be selected and crossed with locally adapted landraces and varieties to achieve breakthroughs in wheat genetic improvement (according to Calanca (2017) and in order to increase tolerance which therefore results in increased yield potential and to respond to climate change (Semenov et al. 2014).

It should be remembered that in all cereals, except wheat landraces, there is an agronomically negative relationship between yield and stress conditions, although higher yield is obtained by cultivation in suitable ecologies with appropriate varieties and cultivation techniques in modern plant breeding programs. However, some agricultural properties that are superior to the various stress conditions can only be achieved by using them as genitors. These genotypes are very important in terms of providing efficiency to the producer and generating income, where stress conditions are common (especially extreme temperature, limited water, etc.) and inadequate. As seen from Table 9.4, durum-type local wheat landraces (more than 113 local wheat landraces) are more cultivated than the aestivum types. And nearly all the genotypes that are being cultivated are called with their morphological traits such as grain or spike color. Even that, the same local cultivars have different name place to place among the farmers.

Table 9.4 Turkey’s climate regions and total vegetation period length of the wheat cultivars and landraces (Anonymous 2017)

Crops of these genotypes are being mostly consumed as regional and healthy dishes (e.g., bulghur, erişte, etc.) due to not only their weak gluten strength but also their nutrition profile (esp. Fe, P, and protein percentage) and poor agronomic traits such as yield level (100–150 kg/da), lateness, short plant height, etc. Wheat landraces are commonly and mainly grown at Black Sea and Central Anatolian regions in Turkey. And these regions are mostly marginal and have suffered from stress factors. Particularly, elevated CO₂ is a very critical and crucial factor for them since their water consumption for grain formation is getting reduced during this process. In addition, consuming water for 1 g dry matter is getting lower for C3 plants including wheat landraces. Generally, the CC and GW’s effect(s) on wheat landraces are (particularly) at vernalization stage, cellular CO₂/O₂ changeability, respiration ratio, maturity, topsoil and subsoil biomass/root volume(s), internode number, weed distribution, germination, rhizome activity, seed longevity, DNA molecule breaking, sterility and ecological factors where their mechanism, etc. have not been fully known and clear today.

Generally, in the cultivation areas, water is a major determining and limiting factor for agricultural yield. On the other hand, the amount of precipitation and its distribution of the water landrace’s vegetation period are ultimately important. Particularly, it is important for the availability of water (directly), nutrient availability, soil fertility, ph value, etc. Water availability has long been known as one of the most important abiotic factors governing crop yield (Boyer 1982; Gray and Brady 2016), and it has played a significant role in plant growth and development processes such as photosynthesis and transpiration. At this point, WUE arises as an important physiological factor which also determines yield. During climate change and global warming, wheat landrace’s WUE value is affected and reduced when the CO₂ is elevated and directly linked with the yield. It can be defined as

$$ WUE\left(\mathrm{kg}\ {\mathrm{da}}^{-1}\ {\mathrm{mm}}^{-1}\right)=\mathrm{Y}/{\mathrm{ET}}_{\mathrm{a}} $$

where Y is the yield (kg da^-1) and ET_a is the actual water consumption (the sum of water consumption for each stage) during the wheat landrace’s growth period (mm) as mentioned above.

CC and GW physiologically affect first WUE, which has an important role in the Calvin cycle in the PSII stage of photosynthesis. When WUE affects, directly reduces the effectiveness of RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) enzyme, which links CO₂ and partly O₂ entrance to the chloroplasts, in other words, results in dry matter production and yield reduction. But, this situation (yield reducing) does not happen in C4 grouped plants and increasing yield aggregating CO₂ in C3 grouped plants (incl. wheat landraces): CO₂ fertilization (Uzmen 2007). In a breeding strategy, selection for elevated water use efficiency causes reduced or earlier flowering that results in lower water usage along with lower yield capacity (Blum 2005). Hence, it is vital to produce genotypes having higher WUE as well as higher yields compared to the present varieties (Farooq et al. 2009). But, this point is clear that despite the significant increase in the yield potential of wheat breeding based on yield worldwide, the future success will be determined by the cooperation of plant breeders and plant physiologists and by the support of physiological criteria (Jackson et al. 1996; Sayılğan 2016) (Fig. 9.9).

Fig. 9.9

Some major yield components of wheat landraces. (Modified from Richards et al. 2015)

9.2 Status in Turkey

When evaluated in terms of topography and climate, Turkey has a very wide genetic diversity and geographical structure. The most important plant is wheat and wheat landraces are still grown in Turkey. Derived end products such as bread, yufka, noodles, lavash, and bulghur are made from wheat. According to the TUİK-2018 and FAO-2017 statistics, Turkey’s wheat sowing area is (7.6–7.7) million ha, its production level is approximately 20 million tons, and its mean yield is (4–4.5) t/ha for common and (2.5–3.0) t/ha durum wheats (Anonymous 2018a, 2019). Wheat landraces in Turkey are usually kept as populations rather than selected as homogenous cultivars. Thus, those populations are characterized by great genetic and phenotypic variations. Landraces even within a single village may show traits such as white, black, or red grain, the presence and absence of awns, tightly or loosely packed spikes, and different abilities to tolerate abiotic conditions (According to Brush 2004 and Karagöz 2014). Wheat landraces are generally grown in small fields and marginal places, in the west and northern transition zones of Central Plateau, and in forest openings of North, Eastern, and Southeastern Anatolia (Akçura 2009), and a full taxonomic list of wheat landraces, which are grown in Turkey, was presented in Table 9.4.

In Turkey, wheat landraces are mostly grown in arid and semiarid regions which are dominated by stress factors such as salinity, drought, and cold (Zencirci et al. 2019). Precipitation, especially in the period of growth of these wheat landraces in arid regions, and high temperatures cause significant decreases in yield level. As mentioned above, their mean yield level is rather lower (100–150 kg/da) compared to modern wheat cultivars’ mean yield level (400–450 kg/da). For determining WUE values of wheat cultivars in Turkey, many types of research were carried out in meteorological stations, i.e., more than 259 (Anonymous 2017) at different 28 climate regions. These climate regions and the total vegetation period length of the wheat cultivars and landraces which are grown in Turkey are presented in Table 9.4.

In Turkey, mostly vegetation period length depends on water availability, temperature, and distribution of the precipitation. According to measurements in the meteorological stations (in total 259), a variation of the WUE value in Turkey can be mentioned like this (Anonymous 2017) (Table 9.5):

Table 9.5 Min. and max. WUE (kg da⁻¹ mm⁻¹) mean values of the Turkish wheat cultivars and wheat landraces in 2019 (Original)

On the other hand, these findings can be evaluated like the following as well:

As seen from Table 9.6, durum and common wheat WUE values are higher than those in wheat landraces in Turkey. It means that except wheat landraces, wheat uses more water and produces more dry matter, resulting in higher yield level. WUE values ​​of landraces are lower than those of durum and common wheat (at least three to four times), and these values should be increased by aggregating the yield. For this purpose, various breeding methods should be used (e.g., mutation breeding) by benefiting from landraces as against stress factors as parents. It was demonstrated that temperature was found to have a positive effect on potential yield as well as earliness within Turkish local wheats, whereas lower drought and heat stress caused varieties from Ethiopia and Syria to have longer spike (Alhajj et al. 2017). But in terms of CC and GW, Turkey is not on dangerous position, but all necessary precautions without delay should be taken into consideration for the sustainability of animal and plant production.

Table 9.6 List of some grown Turkish wheat landraces in 2019 (original)