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TESTING PHILOSOPHY

TESTING PHILOSOPHY . BREEDER VS. OVT. NULL HYPOTHESIS. BREEDER- THERE ARE DIFFERENCES OVT – THERE ARE NO DIFFERENCES. ALPHA LEVEL. BREEDER – NONE NEEDED OVT – Carmer 1976 Crop Sci. 16:95-99. .20 -.40. CHARACTERISTICS OF TEST SITES . BREEDER – HIGH DISCRIMINATION

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TESTING PHILOSOPHY

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  1. TESTING PHILOSOPHY BREEDER VS. OVT

  2. NULL HYPOTHESIS • BREEDER- THERE ARE DIFFERENCES • OVT – THERE ARE NO DIFFERENCES

  3. ALPHA LEVEL • BREEDER – NONE NEEDED • OVT – Carmer 1976 Crop Sci. 16:95-99. .20 -.40

  4. CHARACTERISTICS OF TEST SITES • BREEDER – HIGH DISCRIMINATION • OVT – REPRESENTATIVE OF GROWING REGION

  5. DISCRIMINATION • REGRESS ENTRY MEANS BY LOCATION ON ENTRY MEANS ACROSS LOCATIONS, Ref. Brown, Sorrels, Coffman. Higher ‘b’ values indicate better discrimination

  6. REPRESENTATIVE • OVTs CONDUCTED UNDER OPTIMUM, AVERAGE, AND BELOW-AVERAGE CONDITIONS TO REPRESENT AVERAGE GROWER’S CONDITIONS… Salmon, 1951

  7. NUMBER OF TRIALS BREEDER HAS LIMITED SEED SO NEEDS A FEW DISCRIMINATING SITES OVT PROGRAM NEEDS TO SAMPLE ENVIRONMENTS

  8. HOW MANY SITES ARE USED BY OVT PROGRAMS ?

  9. Average and median number of sites • AVERAGE • BARLEY -5 • CORN – 13 • COTTON – 7 • SOYBEAN -10 • WHEAT - 9 • MEDIAN • BARLEY – 4 • CORN – 9 • COTTON – 6 • SOYBEAN – 8 • WHEAT - 7

  10. RANGE OF ACRES PER TEST SITE • BARLEY – 10,000 TO 30,000 • CORN – 31,000 TO 417,000 • COTTON – 33,000 TO 294,000 • SOYBEAN – 75,000 TO 680,000 • WHEAT – 28,000 TO 457,000

  11. HOW MANY TEST SITES ARE ACTUALLY NEEDED?

  12. Vmean =

  13. WHAT IS AN ACCEPTABLE LEVEL OF PRECISION? LSD = 10% OF THE MEAN SEEMS REASONABLE TO ME !

  14. CORN EXAMPLE • AVERAGE YIELD OF 140 BU/A • LSD = 14 BU/A • NEED S.E. OF MEAN DIFFERENCE= 7.0 • USING 2 YEARS, 5 REPS THEN LOCATIONS NEEDED WOULD BE 4 • AVERAGE NUMBER OF TESTS LOST = 1.5 • SO I NEED 6 TESTS TO COVER 750,000 a

  15. POINTS • NULL HYPOTHESIS – DIFF. VS. NO DIFF. • ALPHA LEVEL – NONE VS. 0.2 • SITES – DISCRIMINATORY VS SAMPLE • SITE NUMBERS – FEW DISCRIM. VS DESIRED LEVEL OF PRECISION

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