Comparative studies for thirty eight genotypes descending from twenty one crosses and the two check varieties Giza 90 and Giza 80 were included in Trial A at Seds Agricultural Experimental Station in 2012 season, eighteen genotypes descending from sixteen crosses and the two check varieties Giza 90 and Giza 80 were grown in Trial B at five locations in Middle and Upper Egypt in the same season. The results obtained from Trial A showed that the strains H5118/2011 and H5124/2011 of the cross (G 83 Rad. x Aust.) x G 91, H5128/2011 and H5129/2011 cross [(G 80 x Aust) x G 83], H5150/2011 cross (G 83rad x Kar) x [(G 83 x G 80) x G 89], H6198/2011 cross[[(G 83 x G 80) x G 89] x (G 83 x Delta Pine)]], H7215/2011 cross [(G 83 x G 80) x G 89] x Aust, H8238/2011 cross (Dand. Rad x Karsh), H9244/2011cross [G 90 x Pima S62 (24240)], H9253/2011 cross [G 91 x Pima S62 (24240)], H10268/2011 [G 83 x (G 72 x Dand.) x G 91], H11281/2011[G 83 x (G 72 x Dand.) x G 85] and Breeder1 of the promising cross [G 83 x (G 72 x 5844)] x G 80] recorded significant higher seed cotton yield (SCY) and lint cotton yield (LY) compared with the check varieties Giza 90 and Giza 80. While the crosses [(G 85 x G 83) x G 90], [(G 83 x G 80) x G 89] x Aust, C.B 58 x G 90, H8249/2010 descending from the crosses G 91 x Pima S62 (24202), [G 83 x (G 75 x 5844) x G 91], [(G 83 x G 72) x Dand] x G 85 respectively and breeder2 of the promising cross (Giza90 x Aus) had higher seed and lint cotton yield (SCY and LY) compared with the check varities Giza 90 and Giza 80 in Trial B. The mean squares of the genotypes in Trial A were highly significant for all yield components traits. Combined mean squares results in Trial B of the genotypes (G) were highly significant and significant for all yield traits except for lint index (LI). Environments (E) mean squares were highly significant for all studied yield traits. Genotypes-environments interactions (G x E) mean squares were highly significant for all yield traits except for lint percentage (L%) which showed significant combined mean squares, indicating change in performance of genotypes from one location to another. In other words, the rank of a genotype differed from one location to another. High heritability estimates in broad sense (h.b.s %) were computed for all yield traits in Trial A, indicated that the environment had slightly influence on these traits. Broad sense heritability estimates (h.b.s %) for yield traits in Trial B were low for seed cotton yield (SCY), lint yield (LY) and boll weight (BW), indicated that the environmental factors had effect on these traits. On the other hand, lint percentage (L %), seed index (SI) and lint index (LI) recorded high heritability estimates in broad sense (h.b.s %) (more than 50%), indicating that environment had considerable effect on these traits.. The G.C.V % values ranged from 2.54% for lint index (LI) to 61.65% for lint yield (LY) in Trial A and ranged from 3.98% for lint percentage (L %) to 50.0% for lint yield (LY) in Trial B. These values indicated variable environmental effects on all studied traits.