A COMPARATIVE STUDY AMONG SOME METHODS FOR EVALUATING STABILITY IN EGYPTIAN COTTO

Abstract

Three methods of estimating genetical stability ( Tai , AMMI and Eberhart and Russell ) for

10 cotton genotypes, [Giza: 45, 80, 83, 77,85, 86,87, 70, 89, (Bahtem!05 x Giza67) (Giza 72 x Delecero )] in 7 Governorates in 1997 and 1998 seasons. Statistical analysis for each season and a combined analysis over both seasons were done and x2 was calculated to

clarity the accuracy of the 3 methods . Cotton yield , its components and fiber technology properties were the traits considered . Results are summarized as follows : 1. The £ values of the studied traits were not significant for the 3 methods indicating that

the levels of stability for each genotype, defined by any method , were mostly the same in both seasons. 2. There was a general agreement between AMMI and Tai methods and their results were different from Eberhart and Russell method . 3. The results of Eberhart and Russell method mostly showed that all genotypes were unstable indicating that this method is not effective in detecting stability of the genotypes . 4.Both AMMI and Tai methods were effective in defining levels of stability for each genotype by means of stability curves and diagrams . 5. AMMI method is more suitable in selecting genotypes with high performance and stability

through biplot of means and scores of each significant IPCA component .