**12.2 Marker-assisted breeding**

• The effectiveness of traditional plant breeding operations has greatly increased with the latest developments in molecular markers. Linkage maps are frequently created using various molecular markers in order to identify quantitative trait loci (QTLs). Cotton markers include:


shown to be beneficial for investigating genetic diversity, genetic mapping of desired phenotypes, determining candidate gene nucleotide sequences and assisting with marker-assisted breeding (MAS). There has been significant progress in identifying QTLs related to agronomic traits, yield components, fiber quality, plant architecture, leaf trichomes, leaf pubescence, seed oil, seed gossypol contents, early maturity, heat tolerance, drought tolerance, salt tolerance, and disease resistance thanks to QTL mapping using a suitable cotton mapping population. In Pakistan, NIBGE-2 and NIBGE-115 were bred using a combination of traditional methods and DNA markers linked to resistance to the cotton leaf curl viral disease. Likewise, MAS was used to produce the resistance genotypes CIM-443 and CIM-240 against the cotton leaf curl viral disease. The CRIS-134 cultivar was found to have a variety of QTLs for drought tolerance when MAS was applied to it. In the meantime, Pakistan's widespread application of molecular markers for MAS is still in its infancy.
