TY  - PRO
AU  - Purchase,J.L.
AU  - Hatting,H.
AU  - Van Deventer,C.S.
ED  - Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Addis Ababa (Ethiopia)
TI  - The use of the AMMI model and AMMI stability value to describe genotype x environment interaction and yield stability in winter wheat (Triticum aestivum L.)
SN  - 92-9146-058-3
PY  - 1999///
CY  - Addis Ababa (Ethiopia)
PB  - CIMMYT
KW  - Adaptation
KW  - Genotype environment interaction
KW  - AGROVOC
KW  - South Africa
KW  - Stability
KW  - Winter crops
KW  - Triticum aestivum
KW  - Yields
KW  - Genotypes
KW  - CIMMYT
N2  - Thirteen winter and intermediate type bread wheat cultivars were evaluated under dryland conditions over a four year period from 1991 to 1994 and over a total of 120 environments in the Free State province of South Africa. The objectives were to determine the suitability of the AMMI model in describing genotype-environment (G x E) interaction, as well as to assess the yield stability of the wide range of genotypes grown under dryland conditions in the Free State province. In all three relatively homogeneous production regions, viz. Western, Central and Eastern Free State, the AMMI model identified distinct patterns of adaptation. The hybrids and long growth period cultivars are generally better adapted to high yield-potentia1 conditions, while the short and medium growth period pure line cultivars are better adapted to lower yield-potential conditions. Since the AMMI model per se does not provide a stability value, the AMMI stability value (ASV) was developed, using the relative IPCA1 en IPCA2 scores, to determine the stability of each genotype across environments. The determination of the ASV has proved most useful in an environment as variable as that in the Free State province
ER  -