A shifted multiplicative model fusion method for grouping environments without cultivar rank change
Crossa, J.
A shifted multiplicative model fusion method for grouping environments without cultivar rank change - 1995 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0011-183X
Genotype x environment interactions of most concern to plant breeders involve cultivar rank change across environments, i.e., cross-over interaction (COI). When COIs are present, cluster strategies can be used to group environments without significant changes in cultivar ranks. Several methods for classifying environments without COI have recently been proposed. In this study, the shifted multiplicative model (SHMM) fusion method based on a building block principle is used for grouping environments which rank cultivars similarly. The SHMM fusion selects the best action by computing for each new cluster formed a new set of distance measures with the other clusters and with the unclustered individuals. Experimental data were collected on 55 spring wheat cultivars evaluated under 5 irrigation levels in each of 2 CIMMYT trials (10 environments). Groups of environments obtained with SHMM fusion were compared with those obtained using cluster analysis based on Euclidean distances computed from unstandardized and standardized data. The SHMM fusion formed 4 final clusters of environments. The final clusters grouped environments with similar irrigation levels. Conventional cluster analysis based on Euclidean distances produced final clusters with much larger percentage of COIs than SHMM fusion. Thus, the data indicated that SHMM fusion is a useful strategy for classifying environments without cultivar rank change
English
1435-0653 (Revista en electrónico)
Crossbreeding
Environmental factors
Genotype environment interaction
Methods
Plant breeding
A shifted multiplicative model fusion method for grouping environments without cultivar rank change - 1995 - Printed
Peer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0011-183X
Genotype x environment interactions of most concern to plant breeders involve cultivar rank change across environments, i.e., cross-over interaction (COI). When COIs are present, cluster strategies can be used to group environments without significant changes in cultivar ranks. Several methods for classifying environments without COI have recently been proposed. In this study, the shifted multiplicative model (SHMM) fusion method based on a building block principle is used for grouping environments which rank cultivars similarly. The SHMM fusion selects the best action by computing for each new cluster formed a new set of distance measures with the other clusters and with the unclustered individuals. Experimental data were collected on 55 spring wheat cultivars evaluated under 5 irrigation levels in each of 2 CIMMYT trials (10 environments). Groups of environments obtained with SHMM fusion were compared with those obtained using cluster analysis based on Euclidean distances computed from unstandardized and standardized data. The SHMM fusion formed 4 final clusters of environments. The final clusters grouped environments with similar irrigation levels. Conventional cluster analysis based on Euclidean distances produced final clusters with much larger percentage of COIs than SHMM fusion. Thus, the data indicated that SHMM fusion is a useful strategy for classifying environments without cultivar rank change
English
1435-0653 (Revista en electrónico)
Crossbreeding
Environmental factors
Genotype environment interaction
Methods
Plant breeding