The effect of co-inoculation of bradyrhizobium and mycorrhizal species on physiological traits and grain yield of soybean (Glycine max L.) under drought stress

Subject Areas : Environmental ecology

Mohammad Ali Mohammad Ali Zirak- Qoturbulagh ¹ , Shahram Mehri ² , Hossein Soleimanzadeh ³ , Mohammad Hossein Ansari ⁴

1 - PhD student in Agrotechnology, Department of Agriculture, Parsabad Moghan Branch, Islamic Azad University, Parsabad Moghan, Iran
2 - Department of Agriculture, Parsabad Moghan Branch, Islamic Azad University, Parsabad Moghan , Iran
3 - Department of Agriculture, Parsabad Moghan Branch, Islamic Azad University, Parsabad Moghan , Iran
4 - Department of Agriculture, Rasht Branch, Islamic Azad University, Rasht, Iran

Received: 2023-03-05 Accepted : 2023-06-17 Published : 2024-09-24

Keywords: "Drought stress", "oil and seed yield ", "mycorrhiza", "rhizobium ", "soybean,

Abstract :

Legumes are sensitive to drought stress and its negative effects can be seen in yield, protein and seed oil. The experimental factors included drought stress at three levels (60, 100 and 140 mm of evaporation from the class A pan) as the main factor and the secondary factor including the combined inoculation of soybean symbiotic bacteria and mycorrhizal fungi species at eight levels (Bradyrhizobium japonicum, Funneliformis mosseae, Rhizophagus irregularis), Glomus fasciculatum, B. japonicum + F. mosseae, B. japonicum + R. irregularis, and B. japonicum + G. fasciculatum along with a control treatment). The results showed that increasing the severity of drought stress in both years decreased plant dry weight, number of pods, number of seeds per plant, biological yield and seed and oil yield in all treatments, but this decrease in some treatments, especially in co-inoculation treatments of B. japonicum + R. irregularis and B. japonicum + G. fasciculatum was less. In all treatments the concentration of chlorophyll a, proline, malondialdehyde (MDA) and superoxide dismutase (SOD) enzyme activity increased under drought stress (100 and 140 mm) in comparison with normal irrigation conditions (I60), it was observed. Of course, the concentration of iron (Fe) and phosphorus (P) in the seed wasn't affected by the interaction of drought stress and microorganisms, and the highest amount of P in the seed was observed at the level of 140mm. Among the treatments, the co-inoculation treatments of B. japonicum + R. irregularis and B. japonicum + G. fasciculatum had a greater effect on improving soybean tolerance to drought than other treatments. Based on the obtained results, it is possible to suggest the inoculation of soybean seeds with B. japonicum bacteria and R. irregularis mycorrhizal species to improve the tolerance of the plant against drought stress and increase the yield of seeds and oil.