The eight cultivars included in this study were two long stable cultivars; Giza 86 and Giza 94 and six extra–long staple; Giza45, Giza 87, Giza 88, Giza 92, Giza 93 and Giza 96. These cultivars were grown at seven locations over the two seasons of 2014 and 2015. These locations were: Kafr El-Sheikh, El-Gharbia, Domietta, El-Sharkeia, El-Beheira, El-Dakahlia and El-Menufia governorates. Analysis of variance for randomized complete block design was done for each location. Then combined analyses of variance were calculated for 8 cultivars, seven locations over two seasons. Differences between means were compared by using the least significant differences (L.S.D.) was done.
The mean squares of seasons were insignificant for all yield components traits, except for lint percentage and seed index. Mean squares of locations and cultivars, had highly significant effects on all yield and its components, except for lint index. Seasons × locations and cultivars × locations interaction mean squares had highly significant effects on yield and its components, except for lint index. Meanwhile, Cultivars × seasons interaction and the second order interaction cultivar ´ season ´ location interaction mean squares had significant effects on seed cotton and lint cotton yields, lint percentage and seed index.
The obtained results pointed out that, Giza 86 cultivar had the highest values for seed cotton and lint cotton yields, boll weight and seed and lint index, followed by Giza 87 cultivar. While, Giza 45 cultivar gave the lowest values for yield and all studied of yield components.
The performance of traits studied significantly varied according to cultivars, seasons, locations and their interactions.