Sampling to determine nodule occupancy of soybean (Glycine max (L) Merr.) by Bradyrhizobium japonicum strains

1998 ◽  
Vol 44 (8) ◽  
pp. 795-799 ◽  
Author(s):  
Cécile Revellin ◽  
Jean-Baptiste Denis ◽  
Gérard Catroux
Keyword(s):  
Glycine Max ◽  
Confidence Interval ◽  
Bradyrhizobium Japonicum ◽  
Sampling Strategy ◽  
Nodule Occupancy ◽  
Experimental Conditions ◽  
Anova Model ◽  
Glycine Max L ◽  
Approximate Confidence Intervals ◽  
Time Required

The confidence interval of the percentage of soybean (Glycine max. (L.) Merr.) nodule occupancy by two strains of Bradyrhizobium japonicum was studied using samples of nodules per plant varying by multiples of 8 (8-56). These samples were recovered from all of the nodules of four sets of 21-24 plants grown in soil colonized only by these strains and typed using strain-specific sera. Approximate confidence intervals (ACI) were estimated (from the ANOVA model) using the formula, length of ACI = 4 [(0.040/P) + (0.278/PN)]1/2, where P is the number of sampled plants and N is the number of nodules characterised for each plant. The estimated ACI decreased when the number of plants sampled increased and decreased to a lesser extent when the number of nodules typed per plant increased. It was possible to define a plant and nodule sampling strategy to minimize the labor and time required to get acceptable ACI values. Under our experimental conditions, when 192 nodules were typed, combinations of 24 plants × 8 nodules per plant and 32 plants × 6 nodules per plant were the most satisfactory, corresponding to calculated ACI of 22.3 and 20.8%, respectively.Key words: Bradyrhizobium japonicum, competition, method, nodule occupancy, soybean.

Phage coating of soybean seed reduces nodulation by indigenous soil bradyrhizobia

1992 ◽  
Vol 38 (12) ◽  
pp. 1264-1269 ◽  
Author(s):  
H. Abdel Basit ◽  
J. Scott Angle ◽  
S. Salem ◽  
E. M. Gewaily
Keyword(s):  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Nitrogenase Activity ◽  
Soybean Seed ◽  
Nodule Occupancy ◽  
Field Soil ◽  
Control Value ◽  
Glycine Max L ◽  
Inoculum Strain ◽  
Plant Basis

Inoculation of soybean with Bradyrhizobium japonicum is often unsuccessful owing to the failure of inoculum strains to nodulate soybeans (Glycine max (L.) Merr.) in the presence of indigenous strains of rhizobia in soil. Previous studies have shown that it is possible to reduce nodulation with indigenous strains of rhizobia by amending the soil with a bacteriophage specific for the indigenous strain. The objective of the current study was to determine whether the coating of seed with phage affected nodule occupancy and soybean growth. A phage specific for B. japonicum USDA 469 and a symbiotically superior strain of rhizobium (B. japonicum USDA 110) were coated together onto soybean seed and planted into both greenhouse and field soil previously inoculated with B. japonicum USDA 469. The phage coated onto seed reduced nodulation by B. japonicum USDA 469 to 48% occupancy, compared with 64% for the untreated control value. Nodulation by the superior inoculum strain was increased from 48 to 82% occupancy by coating seed with the homologous phage and B. japonicum USDA 110. The rate of nitrogenase activity (on a per plant basis) was increased by coating seed with the phage and B. japonicum USDA 110. No other plant or symbiotic parameters were affected by phage coating of seed. These results indicate that the nodulation of soybeans can be significantly affected by the coating of seed with phage specific for undesirable strains of rhizobia in soil and the concurrent coating of seed with desirable strains of rhizobia. Key words: competition, rhizobiophage, rhizobia, soybeans.

scholarly journals Nodulation efficacy of Bradyrhizobium japonicum inoculant strain WB74 on soybean (Glycine max L. Merrill) is affected by several limiting factors

2014 ◽  
Vol 8 (20) ◽  
pp. 2069-2076 ◽  
Author(s):  
Idris Hassen Ahmed ◽  
L. Bopape Francina ◽  
H. Rong Isabella ◽  
Seane Galaletsang
Keyword(s):  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Limiting Factors ◽  
Inoculant Strain ◽  
Glycine Max L

scholarly journals Diversidad de los rizobios que nodulan la soja en los suelos de la Pampa húmeda e identificación de cepas para la fabricación de inoculantes comerciales

2016 ◽  
Author(s):  
◽  
Graciela N. Pastorino
Keyword(s):  
Glycine Max ◽  
Bradyrhizobium Japonicum ◽  
Glycine Max L

Las labores culturales, provocan modificaciones de las propiedades físicas, químicas y biológicas de los suelos. Estas se clasifican en: labranza convencional, labranza vertical y siembra directa. Cada tecnología de manejo genera estreses a los que las poblaciones microbianas se adaptan, como resultado de cambios morfológicos, fisiológicos y genéticos. La inoculación de la soja (Glycine max [L.] Merr) es una tecnología que se introdujo en la Argentina junto con el cultivo y por ello los inoculantes fueron el vehículo de ingreso de las cepas exóticas de Bradyrhizobium, que una vez incorporadas al suelo, se adaptaron y establecieron dando origen a las poblaciones de rizobios naturalizadas. Lo que condujo a generar diversidad a nivel del genoma de los bradyrizobios. El objetivo de este trabajo fue evaluar la diversidad de los simbiontes de soja que se encuentran en la población del suelo y el rol que cumple como recurso en la selección de cepas para la producción comercial de inoculantes. Se evaluaron dos muestras de suelo que durante los últimos 8 años fueron trabajados con siembra directa (SD) y con labranza convencional (LC). Se realizó el recuento y aislamiento de rizobios. Los aislados se caracterizaron fisiológica y genéticamente. La diversidad se evaluó mediante la amplificación de las secuencias BOX A1R. Se seleccionaron 52 aislados que se identificaron amplificando las regiones RSα y nifD y la secuenciación del fragmento ITS 16S - 23S rDNA. El recuento de rizobios mostró que en el suelo bajo SD y antecesor soja la población fue mayor que en la muestra de suelo bajo LC y antecesor maíz. La caracterización fisiológica de 200 aislados reflejó que los suelos LC contuvieron un mayor número de cepas tolerantes a salinidad y alta temperatura. Además un porcentaje mayor de aislados del suelo LC, respecto del suelo bajo SD, resultó con capacidad de sobrevivencia sobre semilla superior a la cepa control E109. Los aislados además presentaron diferencias en la nodulación y fijación de nitrógeno, en la tolerancia a glifosato y en la producción de ácido indol acético (AIA). Sólo un aislado mostró capacidad de solubilización de fósforo. El análisis del dendrograma generado con los fingerprints BOX A1R, mostró que hay mayor diversidad en los suelos bajo SD. Sobre los 52 aislados analizados en base a la secuencia del ITS se encontró que el 70 % son Bradyrhizobium japonicum y 30 % B. elkanii. Se identificaron 4 aislados que comparten características genéticas de ambas especies de Bradyrhizobium. En esta tesis se confirmó que en los suelos con historia de cultivo de soja, manejados bajo distintos sistemas de labranzas, se indujeron cambios a nivel del genoma de las cepas de rizobios que contribuyó a modificar la diversidad de la población. Las poblaciones naturalizadas son un recurso para la identificación de rizobios con características superiores para la fabricación de inoculantes, sin embargo es necesario profundizar las evaluaciones de la supervivencia, tolerancia, competitividad y promoción del crecimiento vegetal de rizobios naturalizados para emplearlos como bioinoculantes.

INFLUENCE OF SINGLE STRAINS AND A COMMERCIAL MIXTURE OF Bradyrhizobium japonicum ON GROWTH, NITROGEN ACCUMULATION AND NODULATION OF TWO EARLY-MATURING SOYBEAN CULTIVARS

1988 ◽  
Vol 68 (2) ◽  
pp. 411-418 ◽  
Author(s):  
L. D. BAILEY
Keyword(s):  
Glycine Max ◽  
Soil Temperature ◽  
Bradyrhizobium Japonicum ◽  
Nodule Formation ◽  
Growth Stages ◽  
Nitrogen Accumulation ◽  
Plant Nitrogen ◽  
Commercial Mixture ◽  
Early Maturing ◽  
Glycine Max L

Seven single strains and a commercial mixture of Bradyrhizobium japonicum were evaluated in association with two early-maturing Canadian soybean (Glycine max (L.) Merrill) cultivars, Maple Presto and Maple Amber. Inoculated and uninoculated plants were grown in pails outdoors. Soil temperature at 15 cm depth was monitored throughout the experiment. At the V2, V3, R2 and R4 growth stages, whole plants were removed from the pails. Nodules were counted and weighed; roots and tops were separated, weighed and analyzed for total nitrogen. Bradyrhizobium japonicum strains 61A148, 61A196, 61A194 and 61A155 were similar in effectiveness, but superior to strains 61A124a, 61A118b, 61A101c and the commercial mixture in earliness of nodule formation, number and weight of nodules per plant, and in promoting greater root and top growth and plant nitrogen accumulation. There were indications that soil temperature may have affected nodulation. Maple Amber showed the greater potential for symbiotic nitrogen fixation. This cultivar supported earlier nodulation, had a greater number of nodules, accumulated more nitrogen in the tops and roots and had greater growth than Maple Presto.Key words: Soybean, Glycine max (L.) Merrill, soil temperature, soybean growth stages, Bradyrhizobium, nodulation

Effects of soil nitrogen status and rate of inoculation on the establishment of populations of Bradyrhizobium japonicum and on the nodulation of soybeans

1989 ◽  
Vol 40 (4) ◽  
pp. 753
Author(s):  
J Brockwell ◽  
RR Gault ◽  
LJ Morthorpe ◽  
MB Peoples ◽  
GL Turner ◽  
...  
Keyword(s):  
Glycine Max ◽  
Soil Nitrogen ◽  
Bradyrhizobium Japonicum ◽  
Clay Soil ◽  
Mineral Nitrogen ◽  
Soil Mineral ◽  
Soil Mineral Nitrogen ◽  
Nitrogen Status ◽  
Mineral N ◽  
Glycine Max L

Soybeans (Glycine max [L.] Merrill cv. Forrest) were grown under irrigation on a well-structured grey clay soil, previously free of Bradyrhizobium japonicum and containing relatively high levels of mineral N, at Trangie, N.S.W. There were two soil pretreatments, pre-cropped (which had the effect of reducing the level of mineral nitrogen in the soil) and pre-fallowed, and four rates of inoculation (B. japonicum CB 1809 - nil, 0.01 X, 1.OX [=normal] and 100X).Mineral nitrogen (0-10 cm) initially was higher in pre-fallowed soil than in pre-cropped soil (37.6 v. 18.5 mg N per kg). Depletion of mineral nitrogen occurred more rapidly in pre-fallowed treatments, so that, 7 days after harvest, mineral-N in pre-cropped soil was significantly higher than in pre-fallowed soil (14.4 v. 10.6 mg per kg).With high levels of soil mineral nitrogen, colonization of seedling rhizospheres by rhizobia and plant nodulation were diminished. These effects were ameliorated but not eliminated by increased rates of inoculation. The development of the symbiosis was also impeded by lower rates of inoculation (0.01 X, 1.OX).

Intra- and inter-specific competition in Rhizobium fredii and Bradyrhizobium japonicum as indigenous and introduced organisms

1987 ◽  
Vol 33 (11) ◽  
pp. 990-995 ◽  
Author(s):  
Stephen F. Dowdle ◽  
B. Ben Bohlool
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Nodule Occupancy ◽  
Soybean Field ◽  
Republic Of China ◽  
Rhizobium Inoculation ◽  
Rhizobium Fredii ◽  
History Of ◽  
Competitive Success ◽  
Glycine Max L ◽  
Different Soils

We studied the competition between Bradyrhizobium japonicum and Rhizobium fredii isolates for nodulation of soybean (Glycine max L. Merrill) cultivars Williams and Ai Jiao Zao grown in three different soils in pots. Two of the soils were from People's Republic of China, one from a soybean field in Honghu with no history of Rhizobium inoculation, and one from a rice field in Wuhan with no history of soybean cultivation. The Honghu soil contained B. japonicum and R. fredii (log total number g−1 = 5.82 ± 0.58); whereas the Wuhan soil only contained B. japonicum (log total number g−1 = 2.80 ± 0.52). Inoculation did not result in a significant increase in nodule number on plants in either soil. Uninoculated plants of both cultivars harbored only R. fredii in the Honghu soil and only B. japonicum in the Wuhan soil. Even when B. japonicum were inoculated into the Honghu soil, R. fredii occupied the majority of the nodules on both cultivars. In the Wuhan soil, B. japonicum serogroups USDA110 and USDA136b (= CB1809) occupied the majority of the nodules except when an isolate of R. fredii from the soybean soil was added in high numbers. In a Hawaiian soil devoid of B. japanicum or R. fredii, when soybeans were inoculated with isolates of both species, most of the nodules were formed by B. japonicum. The R. fredii isolate could form up to 20% of nodules in this soil, but only on the Ai Jia Zao cultivar. In the Wuhan but not the Hawaiian soil, peat pelleting of seeds with equal numbers of two B. japonicum and one R. fredii isolates increased nodule occupancy by B. japonicum USDA136b serogroup significantly as compared with when the same isolates were inoculated into the soil. The results reported here highlight the critical importance of being indigenous to the competitive success of B. japonicum and R. fredii in nodulation of their soybean host.

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