Isoyield Analysis of Barley Cultivar Trials in the Canadian Prairies |
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Authors: | R.-C. Yang D. Stanton S. F. Blade J. Helm D. Spaner S. Wright D. Domitruk |
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Affiliation: | Authors' addresses: Dr R.-C. Yang (corresponding author;e-mail: ), Policy Secretariat, Alberta Agriculture, Food and Rural Development, Room 300, 7000 –113 Street, Edmonton, AB, Canada T6H 5T6 and Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5;Mr D. Stanton, Pioneer Hi-Bred Ltd., 330 –127 Street S.W., Edmonton AB, Canada T6W 1A3;Dr S. F. Blade, International Institute of Tropical Agriculture, c/o Lambourn Ltd., Carolyn House, 26 Dingwall Road, Croydon CR9 3EE UK;Dr J. Helm, Field Crop Development Centre, Alberta Agriculture, Food and Rural Development, Lacombe, AB, Canada T4L 1W8;Dr D. Spaner, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5;Dr S. Wright, Crop Development Branch, Saskatchewan Agriculture, Food and Rural Revitalization, Rm 125 –3085 Albert St, Regina, SK, Canada S4S 0B1;Dr D. Domitruk, Soil and Crop Branch, Manitoba Agriculture and Food, Box 1149 Carman, MB, Canada R0G 0J0 |
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Abstract: | Classification of test sites used for cultivar trials into groups with similar within‐group site performance and response (isoyield groups) is an important step towards identification of appropriate cultivars that are best suited for different productivity levels in farm fields. The objective of this study was to determine isoyield environments in the Canadian prairies based on the analysis of cultivar trials consolidated from individual provinces for barley (Hordeum vulgare L.). Yield data for the analysis were taken from 324 replicated trials at 84 sites across the prairies during 1995–2003. The combined use of regression and cluster analyses of the data normalized for averaging the multi‐year unbalanced data led to a stratification of the 84 sites into 13 isoyield groups. A comparison was made of the distributions of the variability among and within groups according to three modes of grouping: isoyield groups, soil zones and agroecoregions. There was more variability among isoyield groups and correspondingly less within the groups than that among and within soil zones or agroecoreions. Similar contrasting pattern existed for the variance components involving genotype–environment interaction (GEI), although the GEI variability was generally small under all three modes of grouping. Relationships of site sensitivity (regression coefficient) and stability (coefficient of determination) with site productivity were shown to be a useful aid for selecting a subset of test sites in an effort to improve efficiency and quality of future cultivar testing. Thus, isoyield analysis should be a valuable tool for subsetting heterogeneous environments and for reducing GEI impact in cultivar testing and recommendation. |
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Keywords: | cluster analysis genotype–environment interaction isoyield environments site stability |
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