SEPARATION AND IDENTIFICATION OF OROBANCHE SEEDS GERMINATION STIMULATORS THAT PRODUCED BY ROOTS OF FABA BEAN

Abstract

1- Faba bean (Vicia faba L.) is among the most cultivated crop legumes in the world. It is infected with a parasitic weed Orobanche spp. which is a root parasitic flowering plant devoid of chlorophyll which it causes important yield losses worldwide in several crops especially in food and feed legumes. Chemical, physical and biological control methods are used against this weed, but they are not usually enough effective. 2- Roots of the host plants produce germination stimulators of Orobanche spp seeds. The germinated seeds are then grow and attach to the root of the host plant forming an attachment organ that connects between the vascular tissues of the host and parasite. If the germinated Orobanche spp. seeds can't found the host plants during only a few days, it will die. 3- In this study, root exudates of different four Faba bean varieties (two of them are resistant (Misr 1 and Giza 843) and two are sensitive (Nubaria and Misr 3) for the Orobanche infection) were collected and tested for its stimulation efficiency of Orobanche crenata seeds germination. Furthermore, the stimulation activity of the four Faba bean verities were tested by different methods including dual culture method in Petri dishes and pots using both conditioned and non-conditioned O. crenata seeds, under both growth chamber and green house conditions. 4- The highest O. crenata germination stimulation percentage (12%) was obtained from root exudates of Misr 1 Varity, under growth chamber conditions, using conditioned O. crenata seeds. 5- The germination stimulator was extracted from this root exudates by different solvents with gradient polarity, guided with testing of stimulation activity of each extract. Ethyl acetate extract showed stimulation of Orobanche crenata seeds germination.