Monday, 6 October 2008
George R. Brown Convention Center, Exhibit Hall E
The Potential for Wind Dispersal of Orobanche Seeds In Egypt. D. Snyder, T. L. Housley and R. H. Grant Orobanche is a parasitic weed with small seeds. Various Orobanche species are a serious parasite of vegetable crops in the Mediterranean region from Spain to Morocco. The seeds are so small that they can be moved by the prevailing winds. Egypt is planning to develop for production, 400,000 hectares in the south. Has Orobanche in northern Egypt allowed wind dispersal of seeds to these new areas? The movement of the seeds by wind can be predicted from the velocity and direction of the wind and the density of the seeds. Orobanche crenata seeds were collected in a Vicia faba field in El-Rahamnyia, Egypt (70km east of Alexandria). The weight of an individual seed was determined by weighing a sub-sample and then counting the number of seeds. This procedure yielded the relationship y=84x+10,785 (r2=0.764) giving 92 micrograms as the approximate weight of a single seed. The volume of a specific weight of seeds was measured by water displacement of a sub-sample of seeds which was enumerated by evenly dispersing the seeds in agar on a Petri dish then counting the seeds in 10 magnified areas of the plate. In addition volume was calculated from measurements of seed diameter. Measured settling deposition velocities and seed density will be used to estimate seed dispersal in a Gaussian Dispersion model using Egyptian seasonal weather and sand storm wind conditions. Estimation of the reduction of dispersal with low-cost solutions to offer management strategies to decrease seed dispersal.