EFFICIENCY OF DIFFERENT SAMPLING PROBES FOR SAMPLING FROM DIFFERENT KINDS OF SEED LOTS

Transcription

1 EFFICIENCY OF DIFFERENT SAMPLING PROBES FOR SAMPLING FROM DIFFERENT KINDS OF SEED LOTS

2 BACKGROUND

3 A representative sample is critical for achieving an accurate test result. A wide range in types of probes are used among seed control officials in the USA.

4 QUESTION?? Are these probes equally accurate in obtaining representative samples under DIFFERENT SAMPLING CONDITIONS: Homogeneity of the seed lot; Seed size; Seed surface features; Mixture of different types.

5 OBJECTIVE To evaluate performances of different types of probes in use under different sampling conditions

6 MATERIALS AND METHODS

7 CROPS SAMPLED Perennial ryegrass (Lolium perenne L.) Three-way Turfgrass Blend Perennial ryegrass (Lolium perenne L.) Kentucky bluegrass (Poa pratensis L.) Red fescue (Festuca rubra L. subsp. rubra) Wheat (Triticum aestivum L.) Soybean (Glycine Max (L.) Merrill)

8 Seeds sampled Soybean: 6-13 seed/g Wheat: 25 seed/g Ryegrass: chaffy, seeds/g Fescue: Chaffy, seeds/g Bluegrass: chaffy, seeds/g

9 Probes and their codes used in this study

10 Description of Probes used for sampling study Probe No. Length (mm) Diameter Opening (mm) Number Length (mm) Width (mm)

11 Inserted positions for different probes Long types: Number 1, 2, 6, 9 and 10 Shorter types: Number 3, 4, 5 and 7

12 Basic information of seed lots Total lots: 6 Weight per lot: 4000 lbs Number of bags: Eighty (80) 50-lb bags Bags sampled for each lot: 13 randomly chosen bags

13 Table of treatments Lot # 1 Ryegrass 2 Wheat 3 Soybean Crop Colored seed Way to add colored seed into the bag 1.25% red colored 4 Ryegrass:Bluegrass :Fescue (1:1:1) 1.25% (1:1:1) red colored 5 Ryegrass 1% green colored 6 Soybean 2.7% green colored Thoroughly mixed In the center core

14 Statistical analysis Accuracy = (Colored seed found - Expected colored seed) 2 Precision = Variance of the four replicates of each probe MSE = Accuracy + Precision Relative Efficiency (RE) = 100*(MSE i /MSE j ) for comparison of probes i over j χ 2 was used to evaluate the fitness of colored seed found with expected.

15 Performance of probes in detecting red colored ryegrass Probe Bias χ 2 Rank in (%) Precision Overall * ns ** ** ** ns ns 5 3 Hand 2.8 * 8 5 Bias (%) = (Found - Expected) x 100%/Expected.

16 K= Kentucky bluegrass, R=Perennial ryegrass, F=Red fescue Performance of probes in detecting purity components of the blended lot Probe Bias (%) χ 2 Rank in K R F Precision Overall ns ns ns ns ns ns ns ns 6 7 Hand ns 8 5 Bias (%) = (Found - Expected) x 100%/Expected.

17 K= Kentucky bluegrass, R=Perennial ryegrass, F=Red fescue Performance of probes in detecting colored seeds in the blended lot Probe Bias (%) χ 2 Rank in K R F Precision Overall ** ** ** ** ** ** ** ** 8 5 Hand ** 9 6 Bias (%) = (Found - Expected) x 100%/Expected.

18 Performance of probes in detecting red colored wheat seeds Probe Bias (%) χ 2 Rank in Precision Overall * ns ** ns ns ** * 5 4 Bias (%) = (Found - Expected) x 100%/Expected.

19 Performance of probes in detecting red colored soybean seeds Probe Bias (%) χ 2 Rank in Precision Overall ns ns ns * ns 2 2 Bias (%) = (Found - Expected) x 100%/Expected.

20 Performance of probes in detecting red colored seeds in stove-piped soybean seed lot Probe Bias (%) χ 2 Rank in Precision Overall ** ** ** ** ** 2 2 Bias (%) = (Found - Expected) x 100%/Expected.

21 Performance of probes in detecting stained seeds in the stove-piped ryegrass seed lot Probe Bias (%) χ 2 Rank in Precision Overall ** ** ** ** ** ** ** 5 5 Hand ** 8 8 Bias (%) = (Found - Expected) x 100%/Expected.

22 Relative efficiency (R.E.%)* of probes for detecting stained seeds of perennial ryegrass in a ryegrass seed lot. Probe Hand Hand R.E % of probe i in the row over probe j in the column = (MSE j - MSE i ) 100% / MSE I, e.g., the R.E.% of probe 2 over probe 6 = (MSE 6 - MSE 2 ) 100% / MSE 2 =38 (%).

23 Relative efficiency (R.E.%) of probes for detecting stained seeds from a homogenous blend of 33% % Kentucky bluegrass, 33% perennial ryegrass and 33% red fescue. Probe Hand R.E % of probe I in the row over probe j in the column = (MSE j - MSE I ) 100% / MSE I, e.g., the R.E.% of probe 2 over probe 6 = (MSE 6 - MSE 2 ) 100% / MSE 2 =38 (%).

24 Relative efficiency (R.E.%) of probes for detecting stained wheat seeds in a wheat seed lot. Probe R.E % of probe I in the row over probe j in the column = (MSE j - MSE I ) 100% / MSE I, e.g., the R.E.% of probe 2 over probe 4 = (MSE 4 - MSE 2 ) 100% / MSE 2 =16 (%).

25 Relative efficiency (R.E.%) of probes in detecting stained soybean seeds in a wheat seed lot. Probe R.E % of probe I in the row over probe j in the column = (MSE j - MSE I ) 100% / MSE I, e.g., the R.E.% of probe 1 over probe 10 = (MSE 10 - MSE 1 ) 100% / MSE 1 =30 (%).

26 CONCLUSIONS

27 Representative samples are unlikely to be obtained by any probe from heterogeneous seed containers (Seed lots 5 and 6).

28 Representative samples are unlikely to be obtained by any probe from heterogeneous seed containers (Seed lots 5 and 6). However, with certain exceptions, most probes provided a representative sample from thoroughly blended lots.

29 Representative samples are unlikely to be obtained by any probe from heterogeneous seed containers (Seed lots 5 and 6). On the other hand, with certain exceptions, most probes provided a representative sample from thoroughly blended lots. Probes with smaller openings tended to provide samples that under-estimated the longer, more chaffy seed types, while over-representing the shorter, more freeflowing types.

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31 Kentucky Bluegrass Colored Seed - Overall Probe Overall Precision Accuracy Rank Hand

32 Perennial Ryegrass Colored Seed - Overall Probe Overall P recision Accuracy Rank Hand

33 Fine Fescue Colored Seed - Overall Probe Overall P recision Accuracy Rank Hand

34 Kentucky Bluegrass Purity Seeds- Overall Probe Overall Precision Accuracy Rank Hand

35 Perennial Ryegrass Purity Seeds- Overall Probe Overall P recision Accuracy Rank Hand

36 Fine Fescue Purity Seeds- Overall Probe Overall P recision Accuracy Rank Hand

37 Ryegrass (Seed lot A) Colored Seeds-Overall Probe Overall Precision Accuracy Rank Hand

38 Soybean Colored Seeds - Overall Probe Overall Precision Accuracy Rank

39 Soybean Colored Seeds (Stove-piped) - Overall Probe Overall P recision A ccuracy Rank

40 Soybean (Stove-piped)-Precision Probe Ov erall Precision Accuracy Rank

41 Soybean (Stove-piped)-Accuracy Probe Ov erall P recision A ccuracy R ank

42 Soybean-Accuracy Probe Ov erall Precision Accur acy Rank

43 Soybean-Precision Probe Ov erall P recision Accuracy Rank

44 Wheat-Overall Probe Ov erall Precision Accuracy Rank

45 Wheat-Overall Probe Overall Precision Accuracy Rank