Welcome to the 7th ISTA Seminar on Statistics in Seed Testing

29.8. – 2.9. 2005University of Hohenheim

REGIONAL RING TESTVERSUS

PROFICIENCY TEST

DIFFERENCES IN

SAMPLE PREPARATIONSAMPLE PREPARATION&

STATISTICAL EVALUATION

THE BIGININGS

2000 – NATIONAL RING TEST

2003 – REGIONAL RING TEST

INITIATIVE WAS BORN AT THE ISTA QUALITY MANAGEMENT WORKSHOP IN SLOVENIA IN NOVEMBER 2002

Maize Research Institute Zemun Polje

GOALMONITORING AND UPGRADING OF STAFF COMPETENCE

COOPERATION AMONG COLLEAGUES

SERBIA & MONTENEGRO SLOVENIACROATIA ISRAEL GREECEBOSNIA & HERCEGOVINABULGARIA FYROM

PARTICIPANTS

ISTA accredited labnon ISTA accredited lab

GERMINATION ONLY

SEED LOT SELECTION

SAMPLING AND PRELIMINARY TESTING

TOLERANCE CHECK

PACKING AND SAMPLE DISPATCH

SAMPLE PREPARATIONSAMPLE PREPARATION

DIFDIFFFERENCESERENCES (GERMINATION)

SAMPLE PREPARATIONSAMPLE PREPARATION

RING PROFICIENCY

NOT LIMITED 85 – 95%

NO YES

EASY LABORIOUS

VS

GERMINATION LEVEL

HETEROGENEITY TEST

SAMPLE MIXING & DIVIDING

PURITY & OSDSEED LOT SELECTION

SAMPLE PURIFICATIONADDITION OF INERT MATTER & OTHER SEEDSRECORDING THE COMPONETS WEIGHT(PURE SEED, INERT MATTER, OTHER SEEDS)PACKING AND SAMPLE DISPATCH

SAMPLE PREPARATIONSAMPLE PREPARATION

No3

No2

No1

DIFDIFFFERENCESERENCES (PURITY & OSD)

SAMPLE PREPARATIONSAMPLE PREPARATION

RING PROFICIENCY

LIMITS NOT

DEFINED

99.7%0.2%0.1%

YES NO

PURE SEED INERT MATTER OTHER SEED

VS

SAMPLE PURIFICATION

MOISTURE

NO ADJUSTMENT OF MOISTURE LEVEL

ONLY 10 g FOR ANALYSIS

PACKING IN ALUMINIUM FOIL PACKETS

SAMPLE DISPATCH

SAMPLE PREPARATIONSAMPLE PREPARATION

STATISTICAL EVALUATION

CONCEPT OF ISTA PROFICIENCY TESTOVERALL MEAN (ONLY ISTA LABS) NORMALIZED SCORES A, B, C, BMP GRADES

ZZ ==XXii -- XXSDSD

Sum of absolute Z-ScoresA ≤ 3.5B 3.5 < Sum of absolute Z-Scores ≤ 5.3C 5.3 < Sum of absolute Z-Scores ≤ 7.0

BMP > 7.0

STATISTICAL EVALUATION

GERMINATIONRound 05-1 Phaseolus vulgarisNo of participants: 13No of ISTA labs: 7

Normal seedlings

0

5

10

15

20

25

Normalized scores

Num

ber o

f sam

ples

All labs 1

-3 -2 -1 1 2 3

Normal Abnormal Dead seed

S1 S2 S3 S1 S2 S3 S1 S2 S3

Your % 80,00 72,25 88,50 3,50 26,75 6,75 16,50 1,00 4,75

Mean % 81,32 88,29 90,18 3,00 8,46 4,96 15,68 3,18 4,82

SD 1,74 7,54 2,13 2,03 8,83 1,80 2,38 2,21 1,84

Z-scores -0,76 -2,13 -0,79 -1,22 0,25 2,07 0,99 1,10 0,34 -0,99 -0,04 -0,23

Sum abs Z scores 3,67

Lab rating in this test round B

STATISTICAL EVALUATION

RING PROFICIENCY

NOT ADDED TO OTHER

CATEGORIES

WHAT IS THE CURRENT

CONCEPT ?

NO YES

VS

FRESH / HARD SEEDS

IDENTIFICATION OF OUTLIERS

DIFDIFFFERENCESERENCES (GERMINATION)

STATISTICAL EVALUATION

MOISTURE

Round 05-1 Phaseolus vulgaris

No of participants: 13No of ISTA labs: 7Lab rating in this test round ?

What are the grade limitswhen only two samplesare analysed?

Moisture

0

2

4

6

8

10

12

14

16

18

Normalized scores

Num

ber o

f sam

ples

All labs 1-3 -2 -1 1 2 3

MoistureS1 S2 S3

Your % 15,80 11,20 -

Mean % 16,19 11,03 -

SD 0,30 0,46 -

Z-scores -1,30 0,37 - -0,46

Sum abs Z scores 1,67

STATISTICAL EVALUATION

PURITYRound 04-1 xTriticosecaleNo of participants: 13No of ISTA labs: 6Lab rating in this test round A

Pure seed

0

5

10

15

20

25

30

Normalized scores

Num

ber o

f sam

ples

All labs 1

-3 -2 -1 1 2 3

Pure seed Other seed Inert matter

S1 S2 S3 S1 S2 S3 S1 S2 S3

Your % 99,3 99,8 99,6 0,2 0,1 0,2 0,5 0,1 0,2

Mean % 99,25 99,85 99,62 0,22 0,07 0,22 0,53 0,08 0,17

SD 0,10 0,05 0,04 0,04 0,05 0,04 0,10 0,04 0,05

Z-scores 0,48 -0,91 -0,41 -0,28 -0,41 0,65 -0,41 -0,06 -0,32 0,41 0,65 0,24

Sum abs Z scores 1,80 1,46 1,38

STATISTICAL EVALUATION

PURITYRound 04-1 xTriticosecaleLab rating was done according tothe system presented below

Sum of absolute Z-Scores Number of out of tolerance results

A ≤ 3.5 for all components

3.5 < for any component ≤ 5.3

> 5.3 one component

> 5.3 two or more components

0 in all samples or 1 in one sample

B 2 in one sample

C 1 in two samples or > 2 in one sample

BMP 1 in three samples or ≥ 2 in more than one sample

What will the ISTA evaluation system for purity test be?

STATISTICAL EVALUATION

OSDSTATISTICS NOT DONE

ADDED SPECIES ARE JUST LISTED

Round 03-1 Hordeum vulgare

S1 S2 S31 – Polygonumconvolvulus1 – Hordeum murinum1 – Rumex crispus1 – Sorghum bicolor

1 – Bifora radians1 – Convolvulus arvensis1 – Hibiscus trionum1 – Triticum aestivum1 – Triticum durum

1 – Avena fatua1 – Echinochloa crus-galli1 – Myagrum perfoliatum1 – Pisum sativum1 – Triticosecale

SUMMARY

MAJOR DIFFERENCEMAJOR DIFFERENCERING PROFICIENCY

13 150NUMBER OF PARTICIPANTS

VS

QUESTIONIS IT ADEQUATE TO USE THE IS IT ADEQUATE TO USE THE SAME RATING SYSTEM?SAME RATING SYSTEM?

STATISTICAL EVALUATION

GERMINATIONRound 04-3 Beta vulgarisNo of participants: 18No of ISTA labs: 6

Normal Abnormal Dead seed

S1 S2 S3 S1 S2 S3 S1 S2 S3

Your % 65,75 95,50 94,25 6,50 1,00 1,00 27,75 3,50 4,75

Mean % 47,08 92,42 85,88 22,75 2,25 2,13 28,13 5,00 9,71

SD 10,09 2,23 12,30 11,73 1,13 1,31 7,90 1,78 12,80

Z-scores 1,85 1,38 0,68 1,39 -1,39 -1,11 -0,86 -1,12 -0,05 -0,84 -0,39 -0,43

Sum abs Z scores 3,91

Lab rating in this test round B

S1 – NON TREATED SEED

S2 – TREATED SEED

S3 – PELLETED SEED

STATISTICAL EVALUATION

GERMINATION PROBLEMRound 04-3 Beta vulgaris S3 – PELLETED SEED

SUBSTRAT MOISTURE

REGULAR QUANTITY OF WATED

FIRST COUNT : 4TH DAY IS TOO EARLY

RAISED QUANTITY OF WATED

FIRST COUNT BETTER BUT GERMINATION POORER