Abstract
Soils comprise structured biological assemblages and microbial communities must adapt to physical environment and biological constraints. Rhizospheric bacteria called rhizobia interact with roots of legumes to form nodules and perform atmospheric nitrogen fixation. Both plant and bacteria signals contributing to nodule establishment have been shown to play a major role in the specificity of the legume-Rhizobium interaction. The present study aimed to assess if several factors such as cropping systems, N fertilization and application of crop residues affect this specificity. Promiscuous soybean (TGx 1740-2F) was planted in Meru South district (Kenya) every season from March 2007 and three factors were considered: (i) cropping (system monolegume (ML) i.e soybean, association (AS) i.e soybean and maize grown simultaneously or rotation (RO) i.e maize and soybean grown alternately), (ii) Nitrogen fertilization 60 kg.ha-1 (+N or –N) and (iii) maize residues application (+R or –R). Nodulation was assessed and nodules collected during the long rainy season 2008 and the short rainy season 2009. After surface sterilization DNA was extracted and Inter Genic Spacer (IGS) region amplified by Polymerase Chain Reaction (PCR). PCR products were then restricted to obtain Restriction Fragment Length Polymorphism (RFLP) profiles. Results showed that nodulation was not significantly affected by the different factors except N fertilization, regardless the season. Nodule occupancy revealed only 3 main profiles representing 93.6% and 92.5% of all the RFLP profiles obtained from 2008 and 2009 nodules respectively. This suggested a low diversity of native rhizobial strains capable to nodulate the promiscuous variety. The cropping system, N and R application didn't increase the diversity of the rhizobia but results indicated an effect on the distribution of the 3 profiles within the nodules of the plants. Within same treatments, significant differences were found between the two seasons in term of strains occupying the nodules and this may be explained by the shorter rainfall received in 2008 compared to 2009. Results suggest that cropping systems and both N and crop residues applications affect more specifically plant growth and grain yields than the diversity of the native rhizobia nodulating promiscuous soybean variety TGx 1740-2F. (Texte intégral)
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Claims 15
Claim · model-written summary
Nitrogen fertilization significantly affected soybean nodulation.
- Taxon
- soybean
Glycine maxe1 - Material
- TGx 1740-2Fe1
- Treatment
- N fertilizatione0
- Interactor
- rhizobiae2symbiont
- Outcome
- nodulatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nodulation was not significantly affected by the different factors except N fertilization, regardless the season”
e1“Promiscuous soybean (TGx 1740-2F)”
e2“native rhizobia nodulating promiscuous soybean variety TGx 1740-2F”
Claim · model-written summary
Cropping system did not significantly affect nodulation.
- Taxon
- soybeanGlycine maxe2
- Treatment
- cropping systemse1
- Interactor
- rhizobiae3symbiont
- Outcome
- nodulatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nodulation was not significantly affected by the different factors except N fertilization”
e1“cropping systems, N fertilization and application of crop residues”
e2“Promiscuous soybean (TGx 1740-2F)”
e3“native rhizobia nodulating promiscuous soybean variety TGx 1740-2F”
Claim · model-written summary
Crop residue application did not significantly affect nodulation.
- Taxon
- soybeanGlycine maxe2
- Treatment
- application of crop residuese1
- Interactor
- rhizobiae3symbiont
- Outcome
- nodulatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nodulation was not significantly affected by the different factors except N fertilization”
e1“application of crop residues”
e2“Promiscuous soybean (TGx 1740-2F)”
e3“native rhizobia nodulating promiscuous soybean variety TGx 1740-2F”
Claim · model-written summary
Three profiles represented 93.6% of nodule RFLP profiles in 2008.
- Taxon
- soybeanGlycine maxe1
- Interactor
- rhizobial strainse2symbiont
- Outcome
- RFLP profilese0
- Value
- 93.6%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3 main profiles representing 93.6% and 92.5% of all the RFLP profiles obtained from 2008 and 2009 nodules respectively”
e1“Promiscuous soybean (TGx 1740-2F)”
e2“native rhizobial strains”
Claim · model-written summary
Three profiles represented 92.5% of nodule RFLP profiles in 2009.
- Taxon
- soybeanGlycine maxe1
- Interactor
- rhizobial strainse2symbiont
- Outcome
- RFLP profilese0
- Value
- 92.5%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“3 main profiles representing 93.6% and 92.5% of all the RFLP profiles obtained from 2008 and 2009 nodules respectively”
e1“Promiscuous soybean (TGx 1740-2F)”
e2“native rhizobial strains”
Claim · model-written summary
Native rhizobial strains capable of nodulating this soybean variety showed low diversity.
- Taxon
- soybeanGlycine maxe1
- Interactor
- rhizobial strainse0symbiont
- Outcome
- low diversity of native rhizobial strainse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low diversity of native rhizobial strains capable to nodulate the promiscuous variety”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Cropping system did not increase rhizobial diversity.
- Taxon
- soybeanGlycine maxe1
- Treatment
- cropping systeme0
- Interactor
- rhizobiae0symbiont
- Outcome
- diversity of the rhizobiae0
- Direction
- didn't increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Nitrogen application did not increase rhizobial diversity.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Ne0
- Interactor
- rhizobiae0symbiont
- Outcome
- diversity of the rhizobiae0
- Direction
- didn't increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Residue application did not increase rhizobial diversity.
- Taxon
- soybeanGlycine maxe1
- Treatment
- R applicatione0
- Interactor
- rhizobiae0symbiont
- Outcome
- diversity of the rhizobiae0
- Direction
- didn't increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Cropping system affected the distribution of three rhizobial profiles within nodules.
- Taxon
- soybeanGlycine maxe1
- Treatment
- cropping systeme0
- Interactor
- rhizobiae0symbiont
- Outcome
- distribution of the 3 profiles within the nodulese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia but results indicated an effect on the distribution of the 3 profiles within the nodules of the plants”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Nitrogen application affected the distribution of three rhizobial profiles within nodules.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Ne0
- Interactor
- rhizobiae0symbiont
- Outcome
- distribution of the 3 profiles within the nodulese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia but results indicated an effect on the distribution of the 3 profiles within the nodules of the plants”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Residue application affected the distribution of three rhizobial profiles within nodules.
- Taxon
- soybeanGlycine maxe1
- Treatment
- R applicatione0
- Interactor
- rhizobiae0symbiont
- Outcome
- distribution of the 3 profiles within the nodulese0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The cropping system, N and R application didn't increase the diversity of the rhizobia but results indicated an effect on the distribution of the 3 profiles within the nodules of the plants”
e1“Promiscuous soybean (TGx 1740-2F)”
Claim · model-written summary
Rhizobial strains occupying nodules differed significantly between seasons under the same treatments.
- Taxon
- soybeanGlycine maxe1
- Interactor
- rhizobiae2symbiont
- Outcome
- strains occupying the nodulese0
- Comparator
- two seasonse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Within same treatments, significant differences were found between the two seasons in term of strains occupying the nodules”
e1“Promiscuous soybean (TGx 1740-2F)”
e2“native rhizobia nodulating promiscuous soybean”
Claim · model-written summary
Cropping systems and nitrogen and residue applications affected plant growth more specifically than rhizobial diversity.
- Taxon
- soybeanGlycine maxe0
- Treatment
- cropping systemse0
- Interactor
- rhizobiae0symbiont
- Outcome
- plant growthe0
- Comparator
- diversity of the native rhizobiae0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cropping systems and both N and crop residues applications affect more specifically plant growth and grain yields than the diversity of the native rhizobia nodulating promiscuous soybean variety TGx 1740-2F”
Claim · model-written summary
Cropping systems and nitrogen and residue applications affected grain yields more specifically than rhizobial diversity.
- Taxon
- soybeanGlycine maxe0
- Treatment
- N and crop residues applicationse0
- Interactor
- rhizobiae0symbiont
- Outcome
- grain yieldse0
- Comparator
- diversity of the native rhizobiae0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cropping systems and both N and crop residues applications affect more specifically plant growth and grain yields than the diversity of the native rhizobia nodulating promiscuous soybean variety TGx 1740-2F”
The same questions in other papers
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See all 9 papers →nitrogen · ecology: diversity · Glycine max (soybean)Results agree
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.