تأثير مستويات مختلفة من الملوحة في نشاط واعداد بعض السلالات المحلية والاجنبية للرايزوبيا المتخصصة على الماش

Abstract

Factorial experiment was conducted with complcte randomized experiment with three replicates to evaluate the response of six local strains of Rhizobium leguminosarum specialized on iVlungbean Vigna radiate L. which arc isolated from plants cultured at different locations at Baghdad and Al-Anbar governorates, (Abu-Graib, Khan dariy, Al-Radwaney, Al-Karma, Al-Saqlawiya and Al-Halabsi. Ab, Kh, Ra, Kr, Sk and Hl ) respectively, in addition to an imported strain M10 to evaluate their growth in yeast extract -mannitol broth containing different levels of salinity (1.05,2.75, 4.05 ,,5,97,,6.85 and 8.54 dS..m-l) prepared by using drainage water with salinity (EC) of 16 dS.m-rafter inoculation with the corresponding rhizobial cultures. The flaks inoculated in a rotary shaker at 28C" for seven days. Every 24 hours each flask was especially sampled and used for measuring rhizobial growth (optical density) by using a spectrophotometer at waye length 540 nm. The results of experiment indicated that incieasing salinity level of tte ynM broth from 1.05 to 8.54 dS'm-r caused in more than 707o decrease in rhizobial population density. The highest mean (optical density) reading 0.82 was recorded with isolate Ra. While the lowest 0.47 was found with strain Ml0.Gcnerally all examined rhizobial cultures, showed the highest growth after 5 days of incubation, the highest optical density reading 1.66 was recortled after 4 days with isolate Ra under the salinitylcvel of 1.05 dS'm-'.