الفهرس 
Effect of genotypes, seasons, locations, and their interactionsOnly 14 pages are availabe for public view
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Abstract
Cultivars environment interactions are of major importance to cotton breeder in developing improved cultivars . When cultivars are compared over a series of environments, the relative rankings usually differ. For this reason, cotton should be grown under suitable environmental conditions to achieve the highest yield and best quality. The objective of the present investigation was to evaluate the eight cultivars under different environments to recommend the best cultivars for each location and determine the stability in yield, yield components and fiber properties of cotton cultivars . The eight cultivars included in this study were two long staple cultivars ; Giza 86 and Giza 94 and six extra–long staple; Giza 45, 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 (ANOVA) for randomized complete blocks design was don according to Snedecor and Cochran (1982) 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.). The experimental design was a randomized complete block design (RCBD) with four replications in each of fourteen environments (combination of seven locations in two seasons) to recommend the best cultivars for each location, variance components and determine the stability in yield, yield component and fiber properties. The studied characters were, seed cotton yield (k./f.), lint cotton yield (k./f.), boll weight (g.), lint percentage (%) seed index (g.), lint index (g.), micronaire reading, fiber length (mm), fiber uniformity index (%),and fiber strength (g./tex). 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 cultivars 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 93 cultivars had the highest values for seed cotton and lint cotton yields, boll weight and seed and lint index, followed by Giza 87 cultivars. While, Giza 45 cultivar gave the lowest values for yield and all studied of yield components. The performance of the studied traits significantly varied according to cultivars , seasons, locations and their interactions. The mean squares of seasons were highly significant for all fiber traits, except for fiber uniformity index. Location mean squares had highly significant effects on all fiber characters studied, except for fiber length. All studied traits of fiber properties were significantly affected by cultivars . The interaction of seasons x locations were statisticaly significant or highly significant effects on all fiber properties, except for fiber length. The interaction between cultivars × seasons had significant effect on all fiber properties studied, except for fiber length and fiber uniformity index. Moreover, the cultivars × locations interaction had significant effect on all studied characters, except for fiber length (2.5 % span length). The second order interactions had significant effect on all studied fiber properties. from the previous results, it could be concluded that, mean of seed cotton and lint cotton yields of 8 cultivars varied among environments. The wide range of environmental index (EI) for seed cotton and lint cotton yield, indicated significant variation between environments. The environmental indexes covered a wide range and display a good distribution within the range.