Nodulation Compatibility and Symbiotic Performance of Rhizobia spp. With Different Landraces of Bambara Groundnut (Vigna Subterranea (L.) Verdc.) Collections

The symbiosis of the legume bambara groundnut (Vigna subterranean L.Verde) with its rhizobial partners has not been studied sufficiently compared to several other legumes throughout Africa. In this study, a nodulation compatibility screening was conducted on 16 different landraces of this legume using five Rhizobia strains previously isolated from active nodules of Desmodium uncinatum, Arachis hypogaea, Cyamopsis tetragonoloba, Glycine max and Phaseolus vulgaris and deposited at the South African Rhizobium Culture Collection (SARCC). A screening assay was conducted under glasshouse to select compatible rhizobia strains that nodulate and enhance growth in one or more genotypes of V. subterranean (L.) Verdc. Pre-germinated seeds of each landraces planted in sterile river sand medium were inoculated with 108 cfu ml-1 of the rhizobial strains (2ml/seed) and monitored with regular watering for six weeks. Parameters such as nodule number, nodule color and positions, plant biomass were determined in test genotypes. Significant differences were observed among landraces in nodule number and plant biomass, and among rhizobial strains in nodule number. Principal component analysis (PCA) showed that root nodule rhizobia strains SARCC-388 and SARCC-578 characterized as Bradyrhizobium zhangiangens and Bradyrhizobium centrosematis, respectively exhibited the highest nodulation compatibility with one or more bambara groundnut landraces. This study demonstrated that many of the bambara landraces did not show nodulation preference to a unique group of rhizobia, confirming that V. subterranean (L) Verdc can be nodulated by more than one species of rhizobia, especially by rhizobia belonging to the cowpea miscellany cross inoculation group.

Interactive Effects of Biochar, Nitrogen, and Phosphorous on the Symbiotic Performance, Growth, and Nutrient Uptake of Soybean (Glycine max L.)

Numerous studies reported the positive effect of soil amendment with biochar on plant development. However, little is known about biochar and its interrelation with nitrogen (N) and phosphorous (P) additions and their impact on plant growth. We carried out greenhouse experiments to understand the interactive effects of nitrogen and phosphorus supply, as well as biochar amendment, on the symbiotic performance of soybean (Glycine max L.) with Bradyrhizobium japonicum, and plant growth and nutrient uptake. The biochar was produced from maize by heating at 600 °C for 30 min and used for pot experiments at an application rate of 2%. Plants were fertilized with two different concentrations of P (KH2PO4) and N (NH4NO3). Biochar application significantly increased the dry weight of soybean root and shoot biomass, by 34% and 42%, under low nitrogen and low phosphorus supply, respectively. Bradyrhizobium japonicum inoculation enhanced the dry weight of shoot biomass significantly, by 41% and 67%, in soil without biochar and with biochar addition, respectively. The nodule number was 19% higher in plants grown under low N combined with low or high P, than in high N combinations, while biochar application increased nodule number in roots. Moreover, biochar application increased N uptake of plants in all soil treatments with N or P supply, compared with B. japonicum-inoculated and uninoculated plants. A statistical difference in P uptake of plants between biochar and nutrient levels was observed with low N and high P supply in the soil. Our results show that the interactions between nitrogen, phosphorus, and biochar affect soybean growth by improving the symbiotic performance of B. japonicum and the growth and nutrition of soybean. We observed strong positive correlations between plant shoot biomass, root biomass, and N and P uptake. These data indicated that the combined use of biochar and low N, P application can be an effective approach in improving soybean growth with minimum nutrient input.

The Interaction between Bradyrhizobium Japonicum E109 and Azospirillum Brasilense Az39 Improves Bradyrhizobium-Soybean Symbiosis: The Secrets Behind Co-Inoculation

Aims The aim of this work was evaluating the interaction between two of the most widely used strains for soybean inoculation in Argentina, B. japonicum E109 (BjE109) and A. brasilense Az39 (AbAz39). Methods Five treatments were performed: (i) uninoculated seeds; (ii) seeds inoculated with BjE109; (iii) seeds inoculated with AbAz39; (iv) seeds co-inoculated with BjE109 and AbAz39 in a 1:1 proportion (BjE109 + AbAz39) at the seeds sowing and (v) seeds inoculated with a 1:1 proportion of BjE109 and AbAz39 (BjE109-AbAz39) 24 h before seeds sowing. Each treatment was assessed through a seed recovery assay, glasshouse assays and field assays. Results The combination between the two strains improved the ability of BjE109 to survive on soybean seeds after inoculation partially explained by AbAz39’s capacity to produce diverse biologically active molecules. As a result of the greater rhizobial survival on seeds the nodulation values and symbiosis parameters like nodule number, size and biomass and nodulation percentage also increased. In agreement with these observations, combining BjE109 and AbAz39 at strains the grain yield under field conditions were 13,3 and 17,3% greater than single BjE109 inoculation. Conclusions These results here show that the pre-culture combining BjE109 and AbAz39 before the inoculation to the soybean seeds has benefits in plant nodulation and hence production, more than individual inoculation with BjE109 or AbAz39, or the immediate co-inoculation of both strains.

Effect of Seed Treatment and Nutrient Schedule on the Productivity of Blackgram (Vigna mungo L.)

Background: Blackgram (Vigna mungo L.) is an important short duration crop and is grown throughout the country. Seed treatment can improve seedling establishment and better crop stand; it also improves plants ability to tolerate stress at early growth stages and foliar application has the advantage of quick and efficient utilization of nutrients, elimination of nutrient losses through leaching and fixation in soil and also helps in regulating the uptake of nutrients by plants thus improving productivity. Methods: A field experiment was conducted during rabi 2018 at the Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram to assess the effect of different levels of seed treatments and nutrient schedule on the growth and yield of blackgram. The growth attributes, yield attributes and yield viz., number of pods per plant, seeds per pod, length of pod, 100 seed weight, grain yield, haulm yield and harvest index were favorably influenced by the treatments. Result: Seed treatment with borax @ 1 g kg-1 seed and sodium molybdate @ 1 g kg-1 seed were observed superior in increasing plant height (135.84 cm), number of trifoliate leaves per plant (7.61), pods per plant (24.16), length of pod (5.23 cm), 100 seed weight (6.74 g), grain yield (1005 kg ha-1) and harvest index (0.38). Significantly higher nodule number (41.83), effective nodule number (33.83) and weight of nodules (58.83 mg) plant-1 at flowering were documented with sodium molybdate @ 1 g kg-1 seed. In case of seeds per pod significantly higher number of pods per plant (7.33) was observed with borax @ 2 g kg-1 seed and maximum haulm yield (1854 kg ha-1) reported with sodium molybdate @ 1 g kg-1 seed. The basal application of ½ N + full P + ½ K followed by ½ N and ½ K as foliar spray of 13:0:45 at 15, 30, 45 and 60 DAS produced significantly more 100 seed weight (6.52 g), grain yield (872 kg ha-1) and haulm yield (1750 kg ha-1). Interaction effect of boron and molybdenum also showed significant influence with respect to yield attributes and yield.

Effect of P Application Rate and Rhizobium Inoculation on Nodulation, Growth, and Yield Performance of Chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is the world’s third most vital food legume after beans and peas in production level. Yet, its productivity in the last decade has been declined, and it has been contended that the usual native soil rhizobial populations are insufficient/ineffective in N2-fixation. Rhizobium inoculation of the seed may substitute costly N-fertilizers and provide a useful way of achieving sustainable production. Hence, to supply an adequate rhizobial population in the rhizosphere, seed inoculation of chickpea with an effective and importunate rhizobial strain is essential in soils having no/feeble bacterial existence and has revealed optimistic effect on nodule number and mass, growth, yield, and its attributes over uninoculated ones. Its effect has been influenced by N content and P-deficiency of soil, rhizobium strain, variety, T°, pH, salinity, and moisture stress. Phosphorus (P) demand is high in chickpeas, and P deficiency also has a negative effect on chickpea production success. Several research results revealed significant effects of P rate (30–200 kg P2O5 ha−1) on nodule number, mass, and rating plant−1; LAI, RGR, DM, plant height, and branches plant−1; pods and grains plant−1, grain and biomass yields, 100-grain weight, and HI compared to the control. P rates response has been affected by moisture level, pH, available P and N, and variety. Particularly, joint use of P rate and rhizobium inoculation on chickpea has been stated to improve nodulation, growth, and yield and soil fertility. Various studies on the integrated use of P rate and rhizobium inoculation under varying situations showed enhanced nodulation, growth, and yield over the P rate or rhizobium inoculation alone. This might be attributed to adequate P supply and improved utilization with the provision of suitable N2-fixing bacteria for enhanced nodulation and adequate N supply.

Response of Peanut Varieties to Phosphorus and Rhizobium Inoculant Rates on Haplic Lixisols of Guinea Savanna Zone of Ghana

Peanut forms a major component of the predominantly cereal-based farming systems in Northern Ghana. However, yields are low, prompting the need to evaluate the effects of phosphorus (PR) and rhizobium inoculant (IR) rates on growth, nodulation, and yield of peanut varieties. On-station and on-farm experiments were conducted to determine the interaction effects of three P rates (0, 30, and 60 kg P2O5/ha), three IR rates (0, 3, and 6 g/kg seed), and two peanut varieties [Chinese and Nkatie Savannah Agricultural Research Institute (SARI)] on growth, nodulation, and yield of peanut on Haplic Lixisols of Northern Ghana. Both experiments were conducted using a split-split plot design replicated three times for the on-station experiment and on six farmer's fields (on-farm experiment). In both experiments, combined application of 60 kg P2O5/ha and IR at 6 g/kg seed increased pod number in the Nkatie SARI and Chinese varieties compared to their control counterparts. PR × V interaction influenced growth, effective nodule number, and podding capacity with 60 kg P2O5/ha combined with Nkatie SARI to produce significantly higher values. The interaction of IR × V improved pod number, nodule number, and harvest index, such that inoculant at 6 g/kg seed combined with Nkatie SARI gave the best performance. PR × IR also had a significant interactive influence on peanut grain yield. Higher grain yields were recorded from 60 kg P2O5/ha in combination with 6 g/kg seed of rhizobium inoculant. Therefore, these results suggest that the use of P fertilizer at 60 kg/ha and rhizobium inoculant at 6 g/kg seed increase peanut productivity on Haplic Lixisols in Northern Ghana. However, it was prudent not to suggest any recommendations from the P rates in interaction with IR, since the result between the on-station and on-farm experiments appeared not consistent.

BIOLOGICAL NITROGEN FIXATION STABILITY OF COWPEA CULTIVARS WITH TROPICAL SEMI-ARID RHIZOBIAL STRAINS

ABSTRACT Cowpeas (Vigna unguiculata L. Walp) are an economically and socially important legume in northern and north-eastern Brazil and can establish effective symbiosis with nitrogen-fixing bacteria. We evaluated the symbiotic compatibility and efficiency of rhizobial strains from Pernambuco semi-arid soils and determined their symbiotic stability on the IPA-206, BR 17-Gurguéia, and BRS Novaera cultivars, selected for different environments. The experiment was conducted in a greenhouse to evaluate a 3 × 28 factorial arrangement (cultivars selected for different environments × inoculation with the currently recommended strain, uninoculated plants with or without mineral nitrogen, and 25 rhizobial strains from semi-arid soils) in a randomized block design with four replicates. We determined nodule number, shoot and root dry matter, nodule dry matter by nodule number, nitrogen accumulated in the shoot by nodule dry matter, nitrogen content and accumulation in the shoot, relative efficiency of the recommended strain based on nitrogen accumulation, and shoot dry matter. Overall, the cultivars responded differently to different strains and cultivar biological nitrogen fixation potential. Strains G7.85 and BR 3262 showed potential for biological nitrogen fixation. BR 3262 was confirmed to be adequate for inoculation of different cowpea cultivars.

Growth rate and site of pulmonary metastasis to predict lung relapse and overall survival in patients affected by bone and soft tissue sarcomas (B-STS).

11571 Background: Despite surgically resectable pulmonary metastases may lead to cure patients with B-STS (Chudgar NP 2017), a substantial proportion of patients will eventually relapse. Presently, patient selection is based on unique organ involvement, number of metastases, interval between previous surgery and pulmonary progression or relapse. We assessed the impact of anatomical site of metastasis into the lung (as if the pleural site might ease further tumor spreading) and nodule growth rate as additional predictive/prognostic factors of lung progression-free survival (L-PFS) and overall survival (OS). Methods: In our prospectively collected database, we retrospectively evaluated patients operated for B-STS pulmonary progression at 3 different centers from 2005 to 2019. Beyond patients’ clinical features at both baseline and disease progression in the lungs, we focused on whether the relapse occurred into the parenchyma or nearby the pleura (Welter S 2012); secondly, we estimated lung metastasis growth rate, defined as tumor doubling time (TDT) (Nakamura T 2011). Statistical analyses were carried out with IBM SPSS (v. 20.0). Survival outcomes were estimated by Kaplan-Meier method. Hazard ratios (HR) were estimated by Cox regression. Multivariate analysis was performed for both L-PFS and OS according to Cox proportional hazard model. All tests were 2-sided with their corresponding 95% confidence intervals (CI95%). Results: We identified 138 patients who underwent lung metastasectomy [(F=66 (48%); median age at surgery 50 (14-78)]. Median PFS and L-PFS were 8.7 months (CI95% 6.6-10.9) and 8.6 months (CI95% 6.2-11.0), respectively. Median OS was 40.6 months (CI 95% 32.8-48.5). Univariate analysis showed a statistically significant impact of the following variables for both L-PFS and OS: ECOG 0, nodule number <3, being disease-free after first-line treatment, no pleural involvement, and TDT >40 days. Disease-free interval ≤ 24 months and absence of metastases at diagnosis showed significant correlation with L-PFS and OS, respectively. At multivariate analyses the following variables retained statistical significance for L-PFS: TDT >40 days (HR 0.53, CI95% 0.31-0.93, p=0.028); nodule number <3 (HR 0.54, 95%CI 0.29-0.99, p=0.048), no pleural involvement (HR 0.39, CI95% 0.22-0.70, p=0.001); and for OS: TDT >40 days (HR 0.36, CI95% 0.18-0.72, p=0.004), nodule number <3 (HR 0.35, 95%CI 0.18-0.71, p=0.004), no pleural involvement (HR 0.49, CI95% 0.24-0.98, p=0.045), and ECOG 0 (HR 0.29, 95%CI 0.14-0.59, p=0.001). Conclusions: Acknowledging its retrospective nature and the need for an external validation, our series highlights the key-role of the anatomical site of relapse within the lung and the impact of tumor growth rate. If confirmed, these two clinical parameters should be factored in the decision making on performing pulmonary metastasectomy.

Polyvinylpyrrolidone (PVP) and Na-Alginate Addition Enhances the Survival and Agronomic Performances of a Liquid Inoculant of Bradyrhizobium japonicum for Soybean (Glycine max (L.) Merr.)

Nontoxic polymers PVP and Na-alginate may provide a favorable environment for the survival of bacteria. Therefore, PVP and Na-alginate were added to a growth medium to develop a liquid inoculant of Bradyrhizobium japonicum strain. The strain was identified by 16S rDNA sequencing. The addition of PVP (1.8%) and Na-alginate (0.2%) in the medium promoted a better survival (1.93 × 109 cells mL−1) of B. japonicum strain compared to the control (3.50 × 102 cells mL−1) after 6 months of storage. The combination of PVP and Na-alginate ensured 1.53 × 107 cells mL−1 up to 12 months of storage under ambient temperature (28 ± 2 °C), whereas PVP (1.8%) or Na-alginate (0.2%) alone produced similar cell counts only up to 8 months and 6 months, respectively. Consecutive field experiments proved the efficacy of the liquid inoculant on nodulation and yield of soybean. The combination of PVP and Na-alginate-based inoculation of B. japonicum strain significantly increased the nodule number per plant, number of pods per plant, number of seeds per pod, seed yield, and yield per hectare (p ≤ 0.05). Thus, the combination of PVP- and Na-alginate-based inoculation of B. japonicum has great potential to popularize the organic cultivation of soybean.

Effect of rhizobium isolates and nitrogen on nodulation, growth and yield in lentil

The Experiments were setup in three locations, Magura (23°3´ N 89°2´ E), Rangpur (25°7´ N 89°3´ E) and Mymensingh (24°8´ N 90°0´ E), Bangladesh to know the effect of two bacterial strains and 3 nitrogen doses on nodulation, yield and biomass production. The experimental material consists of one lentil popular variety viz., Binamasur-5 which was inoculated with two promising rhizobial starins/isolates namely LB-21 and LB-40 and three levels of nitrogen viz., 25, 50 and 75 kg N ha-1. The inoculant treatments were un-inoculated control (I0), LB-21 (I1), LB-40 (I2) and mixture of LB-21 and LB-40 (I1+I2). Results indicated that nodule number, nodule weight, straw yield and seed yield at the three locations were greater in bacterial isolates treated plants than in control plants. Results further indicated that mixture of two bacterial isolates had no superior effect against any single bacterial isolate. The two isolates (LB-21 and LB-40) had almost similar greater effect on nodule number, nodule weight, physiological parameters and seed yield with being the highest in LB-40. Application of 25 kg N ha-1 under both bacterial isolates performed the best in seed yield. Application of nitrogen at the rate of 75 kg ha-1 had adverse effect on nodulation, growth and seed yield in lentil. Therefore, for getting higher seed yield in lentil, should apply N as basal dose at the rate of 25 kg N ha-1 and the bacterial isolate, LB-40 may be registered as biofertilizer after few more trials in the different lentil growing areas of Bangladesh.