**3.4 Combined effect of biotic and abiotic factors**

Various biotic and abiotic factors are involved in reduction of cotton yield due to which cotton production significantly reduced [12]. On worldwide basis, promptly increasing rate of population highly demands the food and fiber needs to be covered by the rigorous agro-farming practices [6]. But simultaneously this situation have become the big cause of global climatic change that lead to severe environment impacts particularly the water and soil resources deployment [7–10]. This state along with stark in weather measures ultimately affecting the development and growth of crops due to various kinds of stressful field condition at the same time including biotic and abiotic stresses.

The insects are highly dependent on abiotic factors and type of crop for their proper growth and development. The population growth rate is very much during suitable environmental situations and populace abundance is too high. Temperature and relative humidity plays a role in affecting the incidence of these insect pests [88]. Temperature plays a key role in controlling the development of insects and outbreaks of their population [89]. The positive relationship has been found between the population of cotton thrips and environmental factors including degree of hotness, relative humidity and rainfall [90, 91].

Rigorousness of different diseases directly associated with individual functional state of plant, the type of medium or soils, diverse changing weather situations, alike temperature, humidity or rainfall. E.g. during the wet weather condition in sandy type of soils the wilt diseases of cotton occurred more. Same as, high level of moisture and low temperature situation highly favor the growth of blight disease triggered by the *P. exigua* [92]. While on the other hand, severely cold climatic condition or chilling pressure directly influence the vulnerability of cotton crop by the attack of *A. macrospora* [93]. Likewise cold weather with low temperature range and high humidity level favor the diseases caused by *R. solani* and hot weather condition with high degree of hotness with low level of humidity leads the infection by *R. bataticola* in cotton crop [94].

High degree of hotness have direct impact on the sustainable production of cotton crop while indirect effect is increasing the rate of transpiration of water from the soil that ultimately led to drought stress [95]. Thus, the health of soil or soil condition directly influence the relative degree of drought and hotness stress the plants. While as the lower stomatal activity by plants was observed under highly fertile soils in comparison with low fertile soil [96]. Suzuki et al. described the complete survey of combined biotic and abiotic stress effect to cotton crop [97]. Pandey et al. comprehensively reviewed the Impact of Combined Abiotic and Biotic Stresses on Plant Growth and Avenues for Crop Improvement by Exploiting Physio-morphological Traits (**Figure 2**) [98].

*Role of Biotic and Abiotic Factors for Sustainable Cotton Production DOI: http://dx.doi.org/10.5772/intechopen.111914*

**Figure 2.**

*Schematic representation of effect of stress combinations on plants. Source: Pandey et al. [98].*
