Abstract

Stability analysis helps in understanding the adaptability of genotypes over different environmental conditions and the identification of adaptable genotypes. Three field experiments were carried out at the Faculty of Agriculture, El-Fayoum University, Fayoum, Egypt, to study the magnitude and nature of genotype × environment interaction and determine of stability of yield potentiality for five Egyptian cotton varieties. Significant differences were observed among cotton genotypes for seed cotton yield per plant, lint yield per plant, number of open bolls, boll weight, lint % and lint index. Combined analysis showed highly significant between the genotypes, between environments and for Gene–environment interaction of all traits under study. These results showed that genotypes of Giza 90 and Giza 80 were more stable genotypes. This implies therefore that there genotypes are low contribution to the genotypic by environment interaction. Our results showed that high yield genotypes can differ in yield stability, and suggest that yield stability and high mean yield are not mutually exclusive. Therefore, the genotypes Giza 90 and Giza 80 could be used as breeding stock that could be incorporated in crosses with the objectives of improving the previously mentioned traits.

Key words: Cotton cultivars, stability parameters, environment × genotype interactions, potentiality.