This study was carried out to determine heterosis and heterobeltiosis values of F-1 hybrid combinations obtained from Multi Adversity Resistance breeding program and selection of promising hybrids in early generations, and to find out contributions of parents to the heterosis and heterobeltiosis values and ensuring usage of these promising parents in the next cotton breeding programs. In this study, 4 cotton varieties (Tamcot CD 3H, Tamcot HQ 95, Tamcot Sphinx and Tamcot Luxor), developed by Multi Adversity Resistance breeding program, 3 commercial cotton varieties (Maras 92, Stoneville 453 and Sayar 314) and 21 F-1 hybrids obtained by 7 x 7 half diallel quantitative analysis method. Investigation was conducted in the South East Anatolia Agricultural Research Institute's experimental area. The results of the study indicated that there were significant heterotic effects for most of investigated characteristics. F1 hybrids had higher values than parents in terms of investigated characteristics. The seed cotton yield had the highest heterosis and heterobeltiosis values. From the study; 3x6 (Stoneville 453 x Tamcot Sphinx), 3x4 (Stoneville 453 x Tamcot CD 3H) and 2x7 (Sayar 314 x Tamcot Luxor) hybrid combinations were determined as the most promising hybrids in terms of all of investigated characteristics. Contributions of parents to the heterosis and heterobeltiosis values for all investigated characters were detected. The results showed that Stoneville 453, Tamcot Luxor and Tamcot Sphinx had the most contribution to the seed cotton yield, respectively.