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REPORTING DATA

REPORTING DATA. DARYL BOWMAN NORTH CAROLINA STATE UNIVERSITY. BIASES IN USING ARITHMETIC MEANS. HIGHER-YIELDING SITES HAVE A BIGGER INFLUENCE ON ACROSS SITE MEANS MEASURING VARIANCES OF YIELD ACROSS SITES RESULTS IN A MEASURE OF BIOLOGICAL STABILITY NOT AGRONOMIC STABILITY.

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REPORTING DATA

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  1. REPORTING DATA DARYL BOWMAN NORTH CAROLINA STATE UNIVERSITY

  2. BIASES IN USING ARITHMETIC MEANS • HIGHER-YIELDING SITES HAVE A BIGGER INFLUENCE ON ACROSS SITE MEANS • MEASURING VARIANCES OF YIELD ACROSS SITES RESULTS IN A MEASURE OF BIOLOGICAL STABILITY NOT AGRONOMIC STABILITY

  3. RELATIVE YIELD AS A MEASURE OF ENTRY PERFORMANCE IN VARIABLE ENVIRONMENTS S.K. YAU AND J. HAMBLIN. CROP SCI. 34:813-817

  4. RELATIVE YIELD • MEAN YIELD OF AN ENTRY EXPRESSED AS A PERCENTAGE OF THE MEAN YIELD AT THAT SITE • MEAN RELATIVE YIELD IS THE AVERAGE OF INDIVIDUAL RELATIVE YIELDS ACROSS SITES • THE VARIANCE OF AN ENTRY RELATIVE YIELD THEN BECOMES A MEASURE OF AGRONOMIC STABILITY

  5. ADVANTAGES OF USING RELATIVE YIELD • ONE CAN MEASURE AGRONOMIC STABILITY • GIVES EQUAL WEIGHT TO EACH SITE • ALLOWS COMPARISON AMONG ENTRIES IN DIFFERENT EXPERIMENTS

  6. USING ARITHMETIC MEANS

  7. USING RELATIVE YIELD

  8. EFFECT OF HIGH YIELD SITE ON MEANS

  9. USING RELATIVE YIELD

  10. BIAS TO HIGH-YIELDING SITES USING ARITHMETIC MEANS IS LARGE WHEN INDIVIDUAL SITE MEANS DIFFER GREATLY AND ONLY A FEW SITES ARE USED BUT MAY BE TOLERABLE IF RANGE OF SITE MEANS IS SMALL • D.G. PEDERSON. 1986. EFFECTS OF LOGARITHMIC AND SITE MEAN TRANSFORMATIONS ON THE RELATIVE YIELDS FROM A VARIETY TRIAL. EUPHYTICA 35:169-174.

  11. UNCONSCIOUS BIAS AGAINST LOW-YIELDING SITES BY USE OF ARITHMETIC MEANS COULD HAVE THE SAME EFFECT AS DELIBERATELY EXCLUDING STRESSFUL LOW-YIELDING SITES OR ONLY CONDUCTING HIGH-YIELDING SITES YAU AND HAMBLIN 1994

  12. LOW-YIELDING SITES SHOULD NOT BE EXCLUDED FROM THE ANALYSIS P.E. HILDEBRAND. 1990. MODIFIED STABILITY ANALYSIS AND ON-FARM RESEARCH TO BREED SPECIFIC ADAPTABILITY FOR ECOLOGICAL DIVERSITY. P. 169-180. IN. M.S. KANG (ed.) GENOTYPE-BY-ENVIRONMENT INTERACTION AND PLANT BREEDING.

  13. SITES WITH LARGE DIFFERENCES IN ENTRY PERFORMANCE WITHIN SITES TEND TO HAVE A LARGE INFLUENCE ON MEAN RELATIVE YIELD YAU AND HAMBLIN 1994

  14. WITH MULTIPLE SITES ACROSS VARYING ENVIRONMENTS THE IMPACT OF A LOW-YIELDING SITE OR A SITE WITH LARGE GENOTYPIC VARIANCE SHOULD HAVE MINIMAL IMPACT ON THE FINAL ANALYSIS. UNPUBLISHED STUDIES ON THE IMPACT OF DISCARDING LOW-YIELDING SITES SHOWED THAT REMOVING THEM HOWEVER REDUCED PREDICTABILITY (HOW THE ENTRIES WOULD PERFORM THE NEXT YEAR) DARYL BOWMAN

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