Modified AMMI method for measuring performance stability for different genotypes over different environments

摘要

The author suggested some modifications to the additive main effect and multiplicative interaction (AMMI) method to increase its accuracy for measuring stability of genotypes. Using the suggested modifications, four stability levels could be defined. The four stability levels are high, above average, average and below average. The genotype with a high level of stability should have both the first interaction principal component axis (IPCA 1) and the second interaction principal component axis (IPCA 2) equal zero. The level of stability for a genotype with IPCA 1 equal to zero is considered to be above average. The genotype considered to having an average level of stability if its IPCA 2 is equal to zero. Any genotype with IPCA 1 and IPCA 2 not equal zero considered to having below average level of stability. The modified AMMI method was applied to thirty Egyptian genotypes (Gossypium barbadense L.) grown at five locations. The mean squares for environment (E), genotype (G) and GE interaction were highly significant for all traits. The mean square for IPCA1 was highly significant for all traits. The IPCA 2 mean square was significant for boll weight and highly significant for lint yield. The mean square for IPCA 3 was highly significant for lint yield. Four genotypes (F_5 691/91, F_6 795/91, F_6 744/91 and Giza 75) showed a high level of stability for boll weight. For lint yield, four genotypes (M_5 491/91, F_6 678/91, F_5 720/91 and Giza 81) showed a high level of stability. Nine genotypes (M_5 496/91, M_5 507/91, F_5 689/91, F_5 720/91, F_6 794/91, F_6 744/91, F_6 757/91, F_7 893/91 and F_8 901/91) exhibited a high level of stability for lint percentage.