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 Crop Sci. 16:95-99.

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
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