*Article* **Identification and Genetic Mapping of Potential QTLs Conferring Heat Tolerance in Cotton (***Gossypium hirsutum* **L.) by Using Micro Satellite Marker's Approach**

**Shazia Rani 1, Muhammad Baber 2,\*, Tahir Naqqash <sup>2</sup> and Saeed Ahmad Malik <sup>1</sup>**


**Abstract:** High-temperature stress can cause serious abiotic damage that limits the yield and quality of cotton plants. Heat Tolerance (HT) during the different developmental stages of cotton can guarantee a high yield under heat stress. HT is a complex trait that is regulated by multiple quantitative trait loci (QTLs). In this study, the F2 population derived from a cross between MNH-886, a heattolerant cultivar, and MNH-814, a heat-sensitive variety, was used to map HT QTLs during different morphological stages in cotton. A genetic map covering 4402.7 cm, with 175 marker loci and 26 linkage groups, was constructed by using this F2 population (94 individuals). This population was evaluated for different 23 morpho-physiological HT contributing traits QTL analysis via composite interval mapping detected 17 QTLs: three QTLs each for Total Number of Sympodes (TNS), Length of Bract (LOB), and Length of Staminal-column (LOS); two QTLs for First Sympodial Node Height (FSH), and one QTL each for Sympodial Node Height (SNH), Percent Boll set on second position along Sympodia (PBS), Total Number of Nodes (TNN), Number of Bolls (NOB), Total Number of Buds (TNB), and Length of Petal (LOP). Individually, the QTLs accounted for 7.76%–36.62% of phenotypic variation. QTLs identified linked with heat tolerance traits can facilitate marker-assisted breeding for heat tolerance in cotton.

**Keywords:** *G. hirsutum*; molecular markers; morpho physiological characteristics; quantitative trait loci; heat tolerance
