Evaluation of Rhizobium along with Multifunctional Rhizobacteria for Improving the Growth and Yield of Black Gram [Vigna mungo (L.) Hepper]

Pulses are important in Indian agriculture because they provide a substantial quantity of vitamins, protein, minerals and calories to vegetarians (Pingoliya et al., 2014). Black gram, a prominent member of family Fabaceae known as Vigna mungo L. Hepper with the chromosomal number 2n=22. It is believed to have originated in India, where it has been cultivated since ancient times and is one of the country’s most coveted pulse crops. It contains about 24 per cent protein, 60 per cent carbohydrate and 1.3 per cent fat. Black gram seeds are good source of minerals and energy as well as contains ample amount of fibre content and good source of phosphorus. It helps to maintain soil fertility by enhancing soil physical, chemical, biological properties and fixes the atmospheric nitrogen through the mechanism of biological nitrogen fixation (BNF). The crop can be grown as sole and or intercrop and it can tolerant drought and therefore, suitable for dryland areas.
       
Indiscriminate use of inorganic fertilizer, particularly nitrogenous and phosphorous resulted into widespread pollution of soil, air and water. These fertilizers are not only costly but also deplete non-renewable resources such oil, minerals and natural gas etc. (Joshi et al., 2006).  Excessive and long-term use of these chemicals harm soil microorganism, lowers soil fertility and hence diminishes productivity as well as polluting environment (Youssef and Eissa, 2014). Biofertilizer are ecologically acceptable, non-bulky, low-cost inputs that could augment mineral nutrition and play an energetic role in plant nutrition. They are organic substance which contains specific living microorganism, having unique ability to fix atmospheric nitrogen, either non-symbiotically or symbiotically and some microorganism have potential to convert the unavailable (immobile) form of nutrient to available (mobile) form through various biological processes. Keeping this in view, the current investigation was conducted.

This experimental study was conducted at “Tirhut College of Agriculture, Dholi Muzaffarpur” a campus of “Dr. Rajendra Prasad Central Agriculture University, Pusa, Bihar” during kharif season of 2021. The soil of experimental plot was alluvial and having high calcium carbonate ranges from 20-40%. The soil was low in organic carbon (0.36%) and contained 191.8, 22.3 and 139.4 kg ha^-1 available nitrogen, phosphorus and potassium, respectively and pH 8.6 and EC 0.32 dSm^-1. It was estimated that mean maximum temperature during crop season was ranged between 27.9°C to 33.4°C and the minimum temperature ranged between 14.1°C to 27.0°C. The relative humidity fluctuated from 98.0-100% at 7 AM and 73.7%-94.7% at 2 PM. The total rainfall of 675.63 mm was received during the crop season (August-October 2021). There were eight treatments allocated randomly within replications. The variety Pant U-31 was sown in mid of August with a spacing of 30×10 cm using 20 kg ha^-1 seed. Seed was treated with Rhizobium and different rhizobacteria @ 20 gm per 1 kg of seed. The treated seeds was shade dried before sowing. In order to achieve the recommended dose of N, P and K, the amount of Urea, SSP and MOP was 43.7 kg/ha, 225 kg/ha, 33.33 kg/ha respectively. During sowing, the total quantity of all the fertilizers was side dressed in furrows opened at a distance of 5 cm away from the seed row. For crop studies, five selected plants were tagged for taking observations of growth and yield parameters. The results were analysed as per statistically standardized principle of ANOVA technique described by Gomez and Gomez (1984) at 5% level of significance (Fig 1, 2).
 

 

Growth attributes
 
The different treatments did not influence growth parameters except plant height of black gram (Table 1, 2). Co-inoculation of Rhizobium+ PUK-171 (Stenotrophomonas rhizophila) recorded significantly higher plant height (50.95 cm at 50 DAS), number of leaves plant^-1 (27.35, 33.89), number of branches plant^-1(6.15, 7.15), plant dry weight (12.23, 16.22 g), crop growth rate (14.15, 3.80 g m^-2 day) over T₁-Control, T₂-Rhizobium (Bradyrhizobium spp.), T₈ was found at par with rest of treatments. The significant growth attributes due to increasing in the availability of nutrients, particularly nitrogen and phosphorous seems to have played an important role in enhancing cell division and metabolic activities resulting into higher production of photosynthates and their translocation. Similar results were reported by Nalawde et al., (2015).
 

 

 
Nodulation
 
At 25 DAS, the number of nodule plant^-1 (16.23) recorded significantly higher in co-inoculation of Rhizobium + PUK-171 (Stenotrophomonas rhizophila) as compare to T₁-Control, T₂-Rhizobium (Bradyrhizobium spp.) and T₈- application of N as per RDF and found at par with rest of treatments (Table 2). Whereas at 50 DAS co-inoculation of Rhizobium + PUK-171 (Stenotrophomonas rhizophila) recorded significantly higher nodulation over T₁ and T₈. It might be because Rhizobium and multifunctional rhizobacteria have the capacity to promote bacterial development to produce substances that encourage growth, leading to rise in population and ultimately nodule number and their dry weight. Multifunctional rhizobacteria have potential to induce the development of large number of epidermal cell capable of differentiating infectable root hairs. The significantly higher number of nodules with seed pelleting with Rhizobium @ 0.2 kg kg^-1 of seed was also recorded by Vennila et al., (2018).
 
Yield attributes
 
Table 3 shows that the number of pods plant^-1 were maximum (22.5) in T₃ and minimum in control treatment (16.5). The treatments T₃, T₄, T₅, T₆ and T₇ did not show significant differences. The yield attributing character like number of seeds pod^-1, seed index and length of pod did not differ significantly among the different treatments. The differences in pod plant^-1, count of seed pod^-1, pod length and seed index with the inoculation of seed with biofertilizer has been recorded by Siddikee et al., (2018).
 

 
Seed and stover yield
 
The differences in seed yield were significant among the treatments (Table 4). Highest seed yield (1006 kg) was recorded by co-inoculation of Rhizobium + PUK-171 (Stenotrophomonas rhizophila) (T₃), which was significantly superior over control (T₁), Rhizobium (Bradyrhizobium spp.) (T₂) and N as per RDF (T₈) and found statistically at par with Rhizobium+ NE 10 (Bacillus cereus) (T₄), Rhizobium+ Pseudomonas spp. (T₅), Rhizobium + LMSR 45 (Pantoea agglomerans) (T₆), Rhizobium + Methylobacterium (T₇). The treatment T-4 was found significantly superior over control (T₁) and found at par with the remaining treatments. The minimum stover yield (1769 kg ha^-1) was produced under control (T₁). The harvest index varied from 27.91 to 30.47%. The maximum harvest index (30.47%) was recorded under T₃-Rhizobium + PUK-171 (Stenotrophomonas rhizophila) whereas minimum (27.91%) was recorded under control plots. Similar results related to seed yield were observed by Hosseini et al., (2014) by co-inoculation of Rhizobium along with Pseudomonas + Azospirillum. The data regarding seed and stover yield has been given in Table 4 and graphically depicted in Fig 3.
 

 

Based on the results, it is concluded that treatment Rhizobium+ PUK 171(Stenotrophomonas rhizophila) was the most promising since it recorded 26.57% and 53.68% higher CGR during 25-50 DAS and 50 DAS to harvest, respectively. Also 30.80% and 23.90% more number of nodules over control at 25 and 50 DAS, respectively. As a result, highest seed yield (1006 kg), maximum harvest index (30.47%) and B: C ratio (1.54) were also recorded under the same treatment.

None.