Growth promotion and protection against Orobanche foetida of chickpea ( Cicer aerietinum ) by two Rhizobium strains under greenhouse conditions

Fetid broomrape ( Orobanche foetida Poir.) is a chlorophyll lacking holoparasite that subsists on the roots of plants and causes significant damage to the culture of leguminous plants particularly chickpea ( Cicer aerietinum L.). The investigation was done about potential of Rhizobium strains for biological control of O. foetida using a commercial chickpea cultivar (Beja 1) and different Rhizobium strains. Firstly, benefit of bacterial inoculation on plant growth and efficiency in N-incorporation were demonstrated with four isolates, Azm, Bj, Sd.N2 and Sd.N1. Rhizobium strains were investigated for their ability to control O. foetida using pot and Petri-dish experiments. Inoculation of chickpeas with two (Azm and Bj) of the Rhizobium strains induced a significant decrease in O. foetida seed germination and in the number of tubercles on chickpea roots. Furthermore, other symptoms, including the non-penetration of the germ tube of germinated seeds into chickpea roots followed by radical browning and death of the parasite, were observed in the presence of these inoculated chickpea plants. The hypothesis that roots secrete toxic compounds related to Rhizobium inoculation is discussed. Keywords : Biological control, Rhizobium strains, Orobanche foetida , chickpea, necrotic symptoms African Journal of Biotechnology Vol. 12(12), pp. 1371-1377