EFFECT OF SOME SOIL CONDITIONERS AND PLANT GROWTH PROMOTING RHIZOBACTERIA ON SEED PRODUCTION OF COMMON BEAN UNDER WATER STRESS CONDITIONS

Abstract

The present study aimed to investigate the effect of inoculation with arbuscular mycorrhiza fungi as phosphate solubilizer and Hundz soil (HS) and Seaweed extract (SE) as soil conditioners on growth, yield and chemical constituents of common bean plants under drought stress. Two field experiments were conducted, for the two growing seasons of March 2013 and 2014 in a clay soil at the farm of Faculty of Agric., Ain shams Univ. Two samples were taken after 60 days from sowing and at harvest time. Results showed that HS, SE and mycorrhiza led to a significant increase in plant height. All treatments and their interactions showed stimulated effect in branches number per plant, leaves number per plant and leaf area in both seasons. Hundz soil (HS), Seaweed extract (SE) and mycorrhiza have led to increase fresh and dry weights of leaves and fresh and dry weights of branches in both seasons at 60 days from planting comparing with the control. As for the yield components, all three treatments led to a significant increase in pods number per plant, while HS and SE gave the highest values of pods number per plant as compared to the control and rest treatments in both seasons at 60 days from planting. All treatments and their interactions showed a stimulated effect in pod length in both seasons. Pod fresh weight, pod dry weight and pod diameter significantly increased by HS and SE treatments at 90 days from sowing in both seasons as compared to rest treatments. HS, SE and mycorrhiza led to a significant increase in number of seeds per pod and the yield of plant in both seasons at harvest day comparing with the control. HS and the interaction with mycorrhiza and SE treatments gave the best increment of number of seeds per pod and the yield of plant in both seasons. All treatments and their interactions showed a stimulated effect in average number of seeds per plant and seeds yield per Fadden in both seasons. All treatments also caused a significant increase in size and weight of 100 seeds in both seasons. Regarding the chemical constituents, all treatments and their interactions showed a stimulated effect in total chlorophylls reading in leaves of common bean plants at 60 days from planting in both seasons as compared to the control, Seaweed extract and the interaction with mycorrhiza treatments led to the highest value of total chlorophylls reading in both seasons. All treatments led to a significant increase in proline concentration in the second season comparing with the control and the first season at 60 days from sowing. Seaweed extract treatment recorded the highest value of proline concentration in leaves of common bean plants in both seasons as compared to the other treatments. All treatments caused a significant increase in nitrogen, phosphorus and total protein contents and total soluble carbohydrates compared to the control in both seasons. The highest values of protein and nitrogen were observed by Hundz soil (HS) and Seaweed extract in both seasons at harvest stage. Same trends in calcium concentration in common bean seed were recorded by treatments at harvest time in both seasons. Finally, it could be concluded that the most treatments, Hundz soil, Seaweed extract and mycorrhiza caused increase in common bean tolerance to drought conditions.