The present investigation was conducted in the Plant Production Department, Faculty of Agriculture (Saba Basha), Alexandria University during 2016, to investigate the effect of Egyptian cotton variety, lint cotton grade and their interaction on fiber properties. Three commercial Egyptian cotton varieties namely; Giza 96 (belong to extra-long staple length), Giza 94 and Giza 90, which belongs to long staple length as an independent variable were used. Five lint cotton grades coin as; Good / Fully Good, (G/FG); Good +¼ (G+¼); Good (G); Good -¼ (G-¼) and Fully Good Fair/Good, (FGF/G) as the second independent variable were used. This investigation was conducted as a completely randomized design with three replicates and analyzed as a factorial experiment. The obtained results clarified that the all studied H.V.I. fiber properties were highly significant (p ≤ 0.01) affected by the cotton variety. The cotton variety Giza 96 recorded the highest mean values (i.e. 33.97 mm for upper half mean length, 0.854 for maturity ratio as well as cotton variety Giza 94 showed the maximum mean values for uniformity index as 87.04%, short fiber index as 6.31%, fiber strength as 39.48 g / tex, reflectance degree (Rd%) as 77.70%, yellowness degree (+b) as 9.42, trash count as 41.68, trash area as 0.55% and spinning consistency index as 200.00. On the other side, cotton variety Giza 90 revealed the minimum undesirable average values for most tested fiber properties. The highest lint cotton grade (i.e. Good to Fully Good); produced the best fiber quality characteristics for all studied cotton varieties. All studied fiber technological properties were highly significant (p ≤ 0.01) affected by the lint cotton grade. This investigation declared that the interaction between both studied variables was highly significant (p ≤ 0.01) for upper half mean length (U.H.M), length uniformity index (U.I.), short fiber index (S.F.I.), micronaire reading, maturity ratio, bundle strength, elongation (%), color and trash attributes, i.e. reflectance degree (Rd%), yellowness degree (+b), trash count, trash area and spinning consistency index.
