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Biology and Biotechnology of Environmental Stress Tolerance in Plants, Volume 3

used to introgress stress tolerance in cultivated genotype, i.e., conventional

plant breeding and molecular plant breeding, further divided into various

sub-disciplines. This chapter will discuss various plant breeding approaches

for the introgression of tolerance against biotic and abiotic stresses, pros and

cons, limitations, and prospects.

6.1 INTRODUCTION

Biotic and abiotic stresses are the leading factors of yield reduction in the

major crops (Canter, 2018; Zörb et al., 2019). The major abiotic stresses are

temperature, drought, and excess salt, affecting crop physiology and yield

(Waqas et al., 2017; Vaughan et al., 2018; Zafar et al., 2018). The abiotic

stress affects 90% of the land, which minimizes the yield up to 70% (Mantri

et al., 2012). The prediction made on the crop yield models in relation to

the changing climate expresses the loss in yield of many crops, including

maize, rice, and wheat, which may lead to devastating and the most serious

outcomes for food security (Tigchelaar et al., 2018). Through the genetic

mechanism, plants become able to stand biotic and abiotic stress (Roy et al.,

2014; Pradhan et al., 2019). Plant breeding approaches regarding stress toler­

ance in the plant make it tolerant to tackle stress with little effort (Bertoldo

et al., 2014). Plant with the improved genomic structure can tackle multiple

stress with less yield reduction in a variety of environments (Yumurtaci,

2015).

Transgenic approaches are the best tool to improve plant architecture

against the biotic and abiotic stresses, quantity, and quality of economic

products in plants (Wang et al., 2016a, b). Recombinant DNA technology

is the main player to improve the yield potential, nutritional value as well

as shelf life in a severe and delicate situation (Roychowdhury et al., 2013,

2014; Hasanuzzaman et al., 2013; Roychowdhury & Tah, 2013; Roychow­

dhury, 2014; Anumalla et al., 2015; Wani et al., 2016). Recombinant DNA

technology is responsible for many beneficial roles regarding traits improve­

ment and new verities development with novel characteristics (Marco et

al., 2015). Genetically modified (GM) plants have proline, glycine betaine,

and different proteins such as molecular chaperones linked to a defense

mechanism against biotic and abiotic stresses as reported in many field crops

(Grobkinsky et al., 2016; Hasanuzzaman et al., 2015; Anumalla et al., 2016).

Recently, genetic engineering is mostly used weapon to combat biotic and

abiotic stresses in horticultural crops (Bakhsh & Hussain, 2015). In keeping