MODEL FOR GMO IMPURITY QUANTIFICATION IN SOY

BEANS SEED PRODUCTION

Lidia Esteve-Agelet

25th April, 2005

THE GMO IMPURITY CONCERN

The adventitious presence of genetically

engineered material Where do impurities

come from?

Natural sources Cross pollination Segregation Residual seeds

Human handling factors

THE GMO IMPURITY CONCERN

Varietal identity preservation

Consumers pressure Environmental risks Health risks

Lower impurity thresholds

THE GMO IMPURITY CONCERN

The consequences:

Loss of market

Rejected or penalized shipments

Economic loss

OBJECTIVES

Create a simple screening model for predicting the total impurity in soy bean seed production

Identify the critical stages of contamination in the process

THE MODEL-STAGES-

Initial Impurity

Planter

Combine

Truck

Negligible:

-Cross pollination

-Dormant seeds

THE MODEL-ASSUMPTIONS-

30 inches row space in field

Seed rates and yield considered independent

Medium seed size : 28000 seeds = 1 lb

Contamination is additive

Not seed losses, only replaced

Germination of 90%

Homogeneity/perfect mixture/isotropic

THE MODEL-VARIABLES-

X1: Rate seeds/acre: 160.000– 170.000 seeds/acre.

X2: Seed initial impurity in %: 0.5-2%.

X3: Planter impurity in %: over total planted seed. for 1 acre around 0.05% max. (Hanna, 2004)

X4: Yield in bushels per acre. 40-70 bu/ac.

X5: Combine impurity in %: 1 acre around 0.06% max. (Hanna, 2004)

X6: Truck capacity in pounds: 59535 -12000 lb.

X7: Impurity in trucks % over capacity: 0-0.2% (Ruiz-Diaz, 2005)

Independent variables

THE MODEL-VARIABLES-

Dependent variables

Y1: Total impurity in truck (lb) Y2 : % impurity over the total loaded in truck Y3: weight of impurity (lb) /acre of crop

THE MODEL-MAIN EQUATIONS-

Y1 =(((((X2 / 100) * X1 + (X3 /100)*X1)*0.9*X4*(60 / X1)) + + ((X5 / 100) * (X4 / 2800) * 60)) * (X7 / (X4 * 60))) + + ((X6 / 100) * X7)

Y2 = (Y1 / X7) * 100

Y3 = Y1 / (X7 / (X4 * 60))

Excel

Program of the model

(Visual Basic macro)

CONCLUSIONS

The variables required for the model have to be taken from the given ranges in order to get consequent results

Results in accordance with several reports

GMO impurity about 0.1-1% (Quisel, 2004)

0.2-0.6% impurity in oilseeds (Genetic Engineering Newsletter – Special Issue 11/12 , 2003)

The impurity from trucks and initial impurity in seeds are the most relevant pollution sources in the model. Impurity from combine seems to be almost negligible.

ACKNOWLEDGEMENTS

Dr. Thomas J. Brumm for his advises and assessment about the topic

Dr. H. Mark Hanna for the clean out information Dorivar Ruiz-Diaz for the collaboration in programming

and agronomic assessments

Thanks;