Same-Hill Intercropping of Different Plant Species with Faba Bean for Control of Orobanche Crenata
Mahmoud M. Zeid and Doaa A. Komeil
Allelopathic effects of some faba bean companion crops have been shown to reduce Orobanche crenata Forsk. seed germination especially in vitro. Field experiments were conducted in two locations to evaluate the effect of different companion crops grown in the same-hill with seeds of the resistant faba bean cultivars Misr 3 and Giza 843 on the number of emerged crenate broomrape spikes. Another field experiment was established to compare the effect of fenugreek intercropped on the opposite-side of the faba bean ridge method to same-hill intercropping method on the number of broomrape spikes emerged and faba bean performance. A bioassay experiment was also employed to study the effect of presence of fenugreek, fennel and radish on inhibition of O.crenata seed germination in presence of the two faba bean cultivars in vitro. The bioassay results indicated that presence of fenugreek as a companion crop inhibits O.crenata seed germination on both cultivars by almost 30%; however, the values were insignificantly different from the sole-crop. Radish on the other hand, significantly inhibited germination (73%) in presence of Misr 3 only, while fennel showed no effect on parasite seed germination. Field experiments indicated less number of emerged spikes with opposite-side of the ridge when intercropping fenugreek compared to same-hill intercropping. Results also stressed the role of the faba bean genotype in the host-parasite-companion crop complex. The effect of the companion crop on the number of parasite emerged spikes and yield improvement varied according to the location; however, under farmer’s field conditions of a large parasite seed bank, the effect of companion crops was not observed. Companion crops may show allelopathic effects on O.crenata seed germination in vitro, however, these observations need to be verified on farmers’ fields before it could be proposed as a feasible control method for O.crenata.
KEY WORDS: Allelopathy; Coriander; Fennel; Rocket salad; Parsley; Garlic; Radish