Seven cotton genotypes involving cvs. Giza 70, Giza, 77, Giza 86 and Giza 83 and the exotic varieties; Pima S7 and SeaIsland, as well as, the American Upland variety Tamcot C.E., were crossed in a diallel pattern, excluding reciprocals, in 2000 season to produce 21 F1 hybrids. Parents and F1­­'swere evaluated in 2001 season for eight economic traits. Mean squares due to genotypes were highly significant for all traits, revealing the presence of sufficient variability in the population. Significant desired negative mid and better parent heterosis were found for fiber-to-seed attachment force and days to flowering. Significant positive heterosis was also observed for yield and its components. The variances due to general combining ability (GCA) and specific combining ability, (SCA) were significant for all studied traits, indicating the importance of both additive and non additive gene action in the inheritance of these characters. The GCA/SCA ratio was found to be greater than unity, indicating predominance of additive and additive x additive types of gene action in the inheritance of these traits. Based on GCA effects, the Upland variety Tamcot C.E. proved to be the best general combiner for earliness, boll weight, seed index, seed cotton yield and lint cotton yield/ plant. Giza 83 seemed to be good combiner for fiber-to-seed attachment force, Giza 86 for lint percentage and Pima S7 for number of bolls per plant.

Cotton in Egypt has an important economic situation. Thus the study aimed to evaluate the expected economic effects and productivity of environmental factors on Egyptian cotton production. This comes by predicting production yield value and evaluating its return due to cultural and environmental desired and undesired variables. So, convenient production pattern could be determined to obtain maximum yield under these variables effect. The study clarified that expected cotton yield under desired environmental variables will be ranges between 4169-4336 thousand quintar, with an average equal 4253 thousand quintar. This production will realize national net income ranges between 429.37- 474.68 million L.E., with an average equal 452.03 million L. E. Meanwhile, the expected cotton yield under undesired environmental variables ranges between 3171- 3338 thousand quintar with an average equals 3255 thousand quintar. This yield will realize national net income ranges between 33.37- 78.60 million L. E. with an average equals 55.99 million L.E. The study also indicated that cotton crop is one of the extremely affected crops by the environmental and cultural variables extended in its production zones due its long life period. This is detected by its decrease in the production value undesired environmental factors, where this decrease ranges between 23.02% to 23.94% of the