**2. Temperature stress and sugarcane production**

Sugarcane is a C4 species; increase in temperature in the range of 8–34°C increases the carbon dioxide assimilation and improve cane growth during winter but low temperature limit the photosynthesis and leaf growth rate ([11]; **Table 1**). Low temperature below 15°C limited the cultivation of sugarcane but temperature increase under changing climatic condition during low temperature period improve the sugarcane yield [19]. High temperature likely reduce the incidence and severity of frost and extending the growth during winter months, frost known to poor quality in sugarcane [20, 21]. However high temperature has negative effect on sprouting and emergence of sugarcane and ultimate low plant population [22]. Temperature above 32°C result in increased number of nodes, short internodes, higher stalk fiber and lower sucrose [23]. High night temperature usually more number of flowering and flowering in sugarcane ceases the growth of internodes and leaves ultimately reduce the sucrose and cane yield [20]. Increase in temperature under changing climatic conditions also alter the daily evaporation, may cause water stress and more frequent irrigation cycle will be done to meet the demand of evaporation and crop. Frequent irrigation result in over irrigation and create water logging and salinity problem which can reduce the sugarcane yield [24]. Temperature changes also affect the ripening of sugarcane. During winter, low temperature is very important for natural ripening. Under changing climate, elevated temperature reduces the ripening and quality of sugarcane [11].


**Table 1.**

*Climate Change and Agriculture*

future [1].

**Figure 1**.

and extreme events such as floods and drought are projected in future [1]. Due to combustion of fossil fuel, industrial processes and deforestation, atmospheric CO2 concentration has increased by 30% since mid of eighteenth century [2] and projection indicates that CO2 concentration would be double in high emission scenario by the end of this century. Increases in concentration of CO2 and air temperature can be beneficial for some plant [3]. Abiotic stresses, change in rainfall pattern, frequency of extreme low and high temperature, flood and drought are projected in

Changing climatic conditions influences the population dynamics, life cycle duration and overall occurrence of majority of insects, pathogen and weeds of sugarcane. Weeds, pathogen and insects are among the agriculture pest that will be influence by climate change. Changes in temperature, rainfall and CO2 levels, will affect pathogen, insects and weeds distribution and their competitiveness with wheat crop. C3 cultivars are performing well under high CO2 concentration than C4 cultivar. Agriculture sector is sensitive to temporary weather changes and seasonal, annual and long term variation in climate. Agronomic practice, soil, seed, pest and diseases have significant influence on crop yield. Human induced climate change and environmental problems, provides a limiting factor. Sugarcane is a C4 crop, mainly grow in tropics and subtropics regions and important source of bioenergy and sugar in the world. Sugarcane is perennial crop cultivated on 20 million ha in subtropical and tropical region [4] with annual yield app. 1325 million tons stalks for sugar, energy, rum and chemicals [5]. Sugarcane is one of the world's major food-producing crops, providing about 75% of sugar produced in the world for human consumption [6]. Sugarcane is cash crop of Pakistan and makes contribute in 0.6% in total GDP. During 2015–2016, sugarcane crop cultivated on 1132 thousand hectares as compared 1141 thousand hectares previous year, with production of 65,475 thousand tons [7]. Decline in area is due to shifted sugarcane area to other crops. Total cultivated area and production of sugarcane in Pakistan is given in

Sugarcane mostly propagated by placing cutting and whole stalks in furrows. After each harvest, ratoons mostly grows from stubble and it is possible to harvest 20 successful ratoon crop from a single plantation [8] but environmental related factor such as pathogen infection, low winter temperature, weed competition, stalk borer injury and water deficit condition reduce the production one season to next [9]. Climate related and weather events such as temperature, precipitation and atmospheric CO2 are the key factor for sugarcane production in the world [10].

*Total area and production of sugarcane in Pakistan 2002–2016 (Pakistan Bureau of Statistics, 2016).*

**138**

**Figure 1.**

*Temperature stress under changing climatic conditions and its effects on sugarcane crop.*

#### **3. Tolerance mechanism against high temperature stress**

Plant response to temperature stress, vary with degree, duration and plant type. At high temperature, cell death or cellular damage may occur, which lead to catastrophic collapse of cellular organization [25]. Heat stress effect all the process includes germination, growth and yield [26] and the stability of various protein, cytoskeleton structure and efficiency of enzymatic reactions [24, 27]. Under high temperature stress, plant adopt various mechanism include long term phenological and morphological adaptations and short term avoidance mechanism such as transpirational cooling and

**Figure 2.** *Mechanism to cope with high temperature.*

changing leaf orientations. Reduce water loss, closure of stomata, increased stomatal densities and alteration of membrane lipids compositions are the common feature which adopt by plant under stress [17], **Figure 2**. High temperature stress changes the degree of leaf rolling [28].

Low temperature affects the geographical distribution and planting seasons of crops, especially in tropical and subtropical regions [29]. Low temperature retard plant growth and development by reducing the metabolic process, leading to oxidative and osmotic stress [30]. Plant possesses the many strategies to response the temperature fluctuation such as cell remodeling and gene expression and metabolism reprogramming [20, 29]. Under low temperature stress, C-repeat binding factors, bind to dehydration responsive elements in gene promoters to active the COR

**141**

**Figure 4.**

*National loss due to diseases of sugarcane.*

**5. Drought stress**

*Sugarcane Production under Changing Climate: Effects of Environmental Vulnerabilities…*

(cold response genes), called as ICE-CBF-COR pathway [31, 32]. More study shows that miRNAs also play a critical role in this process [33, 34]. Ref. [19] observed the up-regulation of miR139 and down-regulation its target in both cold tolerant and sensitive verities of sugarcane. Some other cold related miRNAs such as miR156K

Increases in CO2 concentration directly affect the photosynthesis and stomatal physiology, increase growth rate in many plants [33]. High concentration with increase temperature will alter the plant ability to grow and modify the distribution of weeds across globe and their competitiveness in different habitat [36, 37]. In C4 plats, internal mesophyll cell arrangement is different as compare to C3 plant; help in efficient transfer of CO2 and increase photosynthesis and reduce the photorespiration [33]. In future under increasing CO2 condition, C4 crop may become more vulnerable to increased competition from C3 weeds. Double concentration of CO2 may decrease 30–40% in stomatal aperture and 25–40% transpiration loss in both C3 and C4 plant. Double concentration of CO2 may decrease 30–40% in stomatal aperture and 25–40% transpiration loss in both C3 and C4 plant. In long term field study, LAI (Leaf Area Index) did not increase in any species under elevated CO2 conditions [33]. Bowes [38] discus that under increasing cons. of CO2, starch cons. Also increases in tissue reduce protein content. Elevated CO2 cons. increase the growth and root-shoot ratio [39] and alter the photosynthesis activity in plants. Plants available nitrogen also reduces under elevated CO2 [40]. Leaves carbon-nitrogen ratio increased under increasing CO2.

Environmental stress reduces the crop productivity and plant growth and drought is the major abiotic stress, affecting crop productivity [41, 42]. Sugarcane

and miR394 has been reported [4, 35] (**Figures 2**–**4**).

**4. Increase in CO2 concentration and sugarcane production**

*DOI: http://dx.doi.org/10.5772/intechopen.81131*

*Sugarcane Production under Changing Climate: Effects of Environmental Vulnerabilities… DOI: http://dx.doi.org/10.5772/intechopen.81131*

**Figure 4.** *National loss due to diseases of sugarcane.*

*Climate Change and Agriculture*

**140**

**Figure 3.**

**Figure 2.**

*Mechanism to cope with high temperature.*

degree of leaf rolling [28].

*Plant responses to abiotic stresses.*

changing leaf orientations. Reduce water loss, closure of stomata, increased stomatal densities and alteration of membrane lipids compositions are the common feature which adopt by plant under stress [17], **Figure 2**. High temperature stress changes the

Low temperature affects the geographical distribution and planting seasons of crops, especially in tropical and subtropical regions [29]. Low temperature retard plant growth and development by reducing the metabolic process, leading to oxidative and osmotic stress [30]. Plant possesses the many strategies to response the temperature fluctuation such as cell remodeling and gene expression and metabolism reprogramming [20, 29]. Under low temperature stress, C-repeat binding factors, bind to dehydration responsive elements in gene promoters to active the COR

(cold response genes), called as ICE-CBF-COR pathway [31, 32]. More study shows that miRNAs also play a critical role in this process [33, 34]. Ref. [19] observed the up-regulation of miR139 and down-regulation its target in both cold tolerant and sensitive verities of sugarcane. Some other cold related miRNAs such as miR156K and miR394 has been reported [4, 35] (**Figures 2**–**4**).
