Effect of Pochonia chlamydosporia var. catenulata (Goddard) Zare & Gams as facultative endophytic fungus on bean (Phaseolus vulgaris L.)

Abstract

The aim of this work was to evaluate the effect of the strain IMI SD 187 of P. chlamydosporia var. catenulata as an endophyte on plant growth promotion of the black bean cv. ´Cuba Cueto 25-9´ (CC 25-9 N). Two experiments were carried out, in vitro and under greenhouse conditions. In vitro, the bean seeds were coated with a mixture of the fungal spores and clay at different doses: 1, 5, 10 and 15% respect to the total weight of the seeds. A negative control with only disinfected seeds and a positive control of seeds coated with the clay (15 %) were used. The germination associated parameters in each treatment were compared. In the greenhouse experiment, the application of the fungus was evaluated by coating the seeds, applying a fungal suspension to the substrate, or by combining them, taking into account the rhizosphere colonization by the strain and the plant growth on the soil: organic fertilizer (3:1 v/v) substrate. The strain IMI SD 187 increased the in vitro germination parameters of the bean seeds, with a significant effect on hypocotyl length and fresh plant weight. High root colonization was achieved with two applications of the fungus, the endophytic root colonization was 16,67 % in 30 days and seed germination was advanced in two days. There was a tendency to increase the parameters number of trifoliate leaves, shoot length, fresh and dry plant weight, and fresh root weight, in different treatments with the fungus compared with the control treatment.