ROLE OF VESICULAR-ARBUSCULAR MYCORRHIZA FUNGI IN PROMOTING GROWTH AND YIELD OF PHASEOLUS VULGARIS UNDER DIFFERENT LEVELS OF PHOSPHORUS AT FIELD CONDITIONS

The effect of inoculation of Phaseolus vulgaris plants grown under different levels of phosphorus with vesicular arbuscular mycorrhizal fungi Glomus mosseae +Gigaspora spp, were studied in field experiment. The experiment comprised of (6) treatments prepared from the interaction of two levels of mycorrhizal inoculation and three levels of phosphorus: 0, 20, 40 KgP/ha. The experimental unit size was (1x2)m. During the experimental period, plants were sampled at two intervals, at flowering 50% of plants and harvesting stages. In the first interval, the following measurements were taken: shoots dry weight, concentration of N and P and percentage of root infection with mycorrhizal fungi. At harvest time number of pods/plants, number of seeds/pods and weight of 100 seed were recorded. The results could be summarized as follows: 1. Inoculation with mycorrhizal fungi caused a significant increase in shoot dry weight, N and P concentrations and root infection percentage at all phosphorus levels that used in the experiment as compared with non inoculation. 2. Addition of phosphorus for non-inoculation treatments significantly increased shoots dry weight, N and P concentration and root infection percentage as compared with P unfertilized treatment. No significant differences were recorded between level 20 and 40 Kg P/ha for the above measurements. 3. Highest number of pods/plant, number of seeds/pod and weight of 100 seed, were recorded in inoculation treatment with mycorrhizal fungi and fertilized by 20KgP/ha (F1P1) as compared with other treatments they were (34.30pod, 6.93seed and 39.64gm), respectively while least values for above traits (15.20pod, 3.12seed and 21.00gm), respectively were recorded in non inoculated and non fertilized treatment (F0P0).