Answer Sheet Corn Germination Referee: Seedling Evaluation

Arbitre de germination SPR de maïs

Red data indicate the error rates

Picture No.

  AOSA (51 participants) M&P (46 participants)

Answer Normal (+) Abnormal (-) unknown Answer Normal (+)Abnormal

(-)

1 -13 38

+38 9

25% 75% 83% 20%

2 -14 37

-22 24

27% 73% 48% 52%

3 +22 28 1

+13 33

43% 55% 2% 28% 72%

4 +51 0

+45 1

100% 0% 98% 2%

5 +37 13 1

+27 19

73% 25% 2% 59% 41%

6 -15 36

+29 17

29% 71% 63% 37%

7 -7 44

-1 45

14% 86% 2% 98%

8*Photo may not clear

-37 14

-35 11

73% 27% 76% 24%

9 -7 44

-11 35

14% 86% 24% 76%

10 -7 44

-2 44

14% 86% 4% 96%

11 +42 9

+38 8

82% 18% 83% 17%

12 +51 0

+43 3

100% 0% 93% 7%

1.Note:Split entire lengthof coleoptile to node

In accordance with M&P this would be classifiedas Normal

Leaf is not badly shreddedor longitudinally split

There is not a deep open crack in the Mesocotyl

AOSA and ISTA:Abnormal:Leaf damaged, coleoptile tip damaged and the coleoptile split more than 1/3 of the length from the tip.

2.Abnormal:

Missing primary root with weak seminal roots.

Note: Mixed opinions whether the seminal roots are “weak”, however, the majority of participants concluded seminal roots are insufficient.

This may need further clarity or guidelines in rules for achieving uniformity in evaluation result.

3.Normal:

Decay in middle of coleoptileis from secondary infection, e.g., test conditions either temperature too warm intowel, or decayed seedling adjacent.

Tissue above and below decayed area is healthy – indicative of secondary infection.

Decay

4.Normal

In towels, there may be considerable twisting of the shoot system.

The shoot is twisting around another seedling in the towel to reach the light or the seed could have been upside down.

Seedlings grown in the dark or in low intensity light will exhibit increased elongation of the coleoptile and Mesocotyl (not this photo).

5.

Normal:

The leaf extends more than ½ way up in the coleoptile.

Hint: Knowing the separation node between the mesocotyl and coleoptile.

6.Normal for M&P Leaf is not badly shredded or longitudinally split, no deep crack in the mesocotyl.

Abnormal for AOSA and ISTA

- Leaf damaged, coleoptile tip damaged

if the first leaf has emerged at time of evaluation, seedling is abnormal if the coleoptile has any of the following defects together with damage to the first leaf --coleoptile split for more than one-third of the length from the tip.--coleoptile strongly bent over.--coleoptile tip damaged or missing.--coleoptile split at any location below the tip.

7.

Abnormal:

The leaf extends less than ½ way up the coleoptile.

8.Abnormal:

Split in coleoptile - visible from the beginningof spiral, and down through mesocotyl.

Tight spiral is considered as normal in rules, but a close exam of the essential structures is necessary, e.g., deep split in mesocotyl.

Note: Photo may not show clearly the crack in the mesocotyl.

split

split

9.Abnormal:

Deep open crack in Mesocotyl

10.Abnormal

Seedling is weak, stunted at the endof test duration – appears to be some “browning at point of attachment.

Stubby primary root with weak seminal roots.

browning

11.

Normal

Two shoots from one seed are normal as long as they arenot fused together and/or provided one is “normal” with no seedling structures impaired.

See M&P: 4.12.6

12. Normal – sufficient growth – all essential structures arevisible and no defects, - healthy shoot and root