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| Titel |
Rhizoctonia solani infection reduced by bacterial and fungal combination of
biofertilizer inoculums on organic potato |
| VerfasserIn |
Orsolya Papp, Borbala Biro, Eva Abod, Timea Jung, Imre Tirczka, Dóra Drexler |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147759
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| Publikation (Nr.) |
 EGU/EGU2017-11965.pdf |
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| Zusammenfassung |
| Soil biological functioning and proper agrotechnical management are of key importance in
organic agriculture. Beneficial microbial inoculums are used either as plant strengthening
products (psp) or also as plant protecting products (ppp). Question is, which type of microbes
should be applied to certain soil-plant systems to improve yield or reduce the damage of
soil-born plant pathogens? Objective of present study was to compare the effect of inoculums
1 (PPS) with plant growth promoting bacterium strains (PGPR) and inoculums 2 (TPB) with
potential biocontrol-agents, including both fungi and bacteria in organic potato
production.
Field experiment was conducted at the Organic Research Station of the Szent István
University (Babatpuszta, Hungary). Growth and quality of potato (Solanum tuberosum var.
Demon) was studied in the two microbial treatments and control, in four replicates. The PPS
inoculums included Pseudomonas protegens, Ps. jessenii and Strenotrophomonas
maltophylia, with plant growth promoting (PGPR) effect. TPB inoculums consisted of
Trichoderma hartianum, Pseudomonas putida and Bacillus subtilis strains with main
biocontrol effects of fungal and bacterium combination. Strains were incubated for 24 hours
at 28 oC in a rotary shaker (140 rpm/min) up till cell-number about 1010 cell.ml-1 in Nutrient
broth substrate, and mixed to prepare combined inoculums. Each potato tuber was treated by
10 ml inoculums that was added to 100 ml water respectively with only water at the
controls. Yield of potato (10 plants/plot) and tuber quality, i.e. the percentage ratio of
scabbiness (Streptomyces scabies), Rhizoctonia solani, and Fusarium sp. infection was
estimated. Abundance of total aerob and anaerob heterotrophs, total microscopic fungi,
pseudomonads bacteria and some sporeforming microorganisms was assessed by the
most probable number (MPN) method in soil samples, collected four times during
vegetation. Soil enzyme, dehydrogenase (DH) and fluorescein diacetate (FDA)
activity was estimated, beside soil physical and chemical characteristics. Statistics,
including binomial logistic regression was used for evaluation (IBM SPSS Statistics 22
software).
Aerobic MPN counts were reduced by 0,5 value, anaerobic however were increased by 2
order of magnitude at the end of vegetation period. Both inoculums reduced the fungal counts
at 60% of flowering stage, but PPS inoculums improved also the abundance of pseudomonads
bacteria in the soil at all sampling stages. Soil dehydrogenase (DH) activity showed a strong
seasonal variability, which was about 20-times higher at flowering of potato, more
particularly at TPB inoculums. Although yield parameters were only tendentiously improved,
the presence of Rhizoctonia solani infected tubers was significantly less likely (by
70,3%) with TPB inoculums combination. We assumed that presence of biocontrol
type of Trichoderma fungi in TPB inoculums was the reason for such a significant
reduction of Rhizoctonia infection. Necessity of previous monitoring of soil-health,
including the microbial status of potential biocontrol strains is concluded. The tuber
quality of organic potato may be enhanced by using the inoculums tested in this
study.
Thematically belongs to Biochar (Piac-13-1-2013-0274) and Biofector (GA 312117)
projects. |
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