Effect of Intercropping by Flax, Radish and Fenugreek on Faba Bean, Vicia faba L., Production and Reduction of Orobanche crenata Forsk Seed Bank

Faba bean Vicia faba L. is a primary source of protein in the diet of masses in Egypt. Broom-rape, Orobanche crenata Forsk (Orobanchaceae), present great threat parasitic weed to some crops in Egypt including faba bean. Egyptian farmers were forced to abandon growing faba bean crops due to O. crenata heavy soil infestation. Several methods have been used for controlling this parasite, but without obvious success. Many researches have shown that intercropping has been more effective than monocropping in suppression of parasitic weeds. The effect of intercropping (fenugreek, radish and flax) using two resistant cultivars (Giza 843& Misr 3) on the emergence of the broomrape spikes and faba bean production were carried out. Intercropping flax or fenugreek among faba bean cultivars, caused a significant reduction in the infestation levels of O. crenata and increased the faba bean yield compared with sole treatments. Flax was more effective in the reducing infestation rate by O. crenata than fenugreek. This reduction appeared to be related to reduced seed germination which may have been as a result of allelochemicals released by fenugreek roots, though this was not confirmed in this study. The reduction in weed infestation was more pronounced in Giza 843, than in Misr 3. Flax treatment showed the lowest weed infestation compared with other intercropping treatments. Fenugreek intercropping treatment resulted in the highest pod yield for both Giza 843 and Misr 3. Using resistant cultivars intercropping with fenugreek or flax is very promising trend that generally combines both good yield and low number of emerged spikes that reduce broomrape seed bank in the infected soils, with variations depending on the cultivar and growing season.