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To characterize twenty Rhizobium strains isolated from nodules of lentil, grasspea and chickpea, an experiment was conducted in the Soil Microbiology laboratory of the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh. The isolates were tested for growth on Congo red Yeast Extract Mannitol (YEM) agar, peptone glucose agar, and YEM agar containing Bromothymol blue (BTB). All the strains except Ls 12 absorbed Congo red dye very weekly. Except Le 2 strains, isolated from lentil showed no growth in peptone glucose agar. All the strains isolated from grasspea and chickpea showed moderate growth on this medium. All the strains were fast-growing and showed acidic reaction on YEM agar medium. Among the strains isolated from lentil, Le 1, Le 2 and Le 4 produced moderate turbidity while Le 3, Le 6, Le 7 and Le 8 produced high turbidity in YEM broth. All the strains isolated from grasspea except Ls 3 and chickpea except Ca 1 produced moderate turbidity in YEM broth medium. Strains Ls 3 and Ca 1 produced high turbidity. To assess the effect of ten of these Rhizobium isolates viz. Le 1, Le 4, Le 6, Le 8, Ls 1, Ls 2, Ls 6, Ls 7, Ca 3 and Ca 4 on growth and biomass production of rice, a follow-up experiment was conducted in the same laboratory. Root length of rice was significantly increased over control (without inoculation) due to inoculation with different Rhizobium strains. The highest root length (9.63 cm) was obtained by inoculation with strain Ls 6 isolated from lentil. All the Rhizobium strains produced significantly higher shoot length, fresh and dry biomass over control. The highest shoot length (16.50 cm), fresh biomass (138.3 mg) and dry biomass (27.75 mg) were also obtained from the strain Ls 6.

Plant growth promoting rhizobacteria (PGPR) stimulate plant growth by producing phytohormone which enhances the growth and physiological activities of the host plant. Recently, legume bacteria (Rhizobium spp.) have been considered as a PGPR for legume as well as non-legumes and have the potential for growth stimulation. A laboratory experiment was conducted to observe the effect of PGPR and Rhizobial inoculation on seed germination, seedling emergence, growth and development of lowland rice variety MR219. The experiment was conducted under laboratory condition using filter paper in Petri dish. The design of the experiment was completely randomized (CRD) with six replicates. The PGPR strains UPMB10 (Bacillus sphaericus), Rhizobium strains SB16, UPMR1006 and UPMR1102 were used in the experiment. Seeds inoculated with those PGPR and Rhizobium strains and the Petri dish were kept in an incubator at 30 ± 2°C for 120 h. The seeds germination and other related attributes were measured. The results suggested that inoculation significantly increased the seedling emergence, seedling vigor, root growth namely root length, root surface area and volume. Among the strains, UPMB10 performed better in seedling growth and strain UPMR1006 produced profuse hair in the radical. The results concluded that PGPR and Rhizobia strain can promote seed emergence and seedling attributes which benefits the early seedling establishment and consequently the crop growth and development.

Passion fruit has great prospective to fascinate fruit consumer for its taste and delicious fruit juice and improvement of the economic condition of the fruit grower in the developing countries. The self-incompatibility in the passion fruits is an imperative reason to be considered regarding fruit production. Pollination is an essential for self-sterile crops as passion fruit (Passiflora edulis Sims.). The experiment was conducted in the field and laboratories of the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, Bangladesh to investigate the fruit setting behavior of passion fruits at during five flashes. We estimated to study fruit setting behavior of passion fruit at different flashes and determine effective pollination method and suitable flashes among five flashes. Result revealed that percent of fruit set of passion fruit was recorded highest; Seeds per plant were recorded highest in third flash when flowers were pollinated by hand compared with self-, and natural pollinations. Length-breadth ratios of fruits in third flashes were recorded higher when pollinates by hand. Individual fruit weight was also recorded higher at third flash. Plants required minimum days from flower anthesis to full maturity during third flash. On the other hand, fruit growth behavior of hand pollinated flowers was recorded higher during third flash of passion fruit. Results indicated that all studied characteristics of fruit and seed of passion fruit of third flash performed best.

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Reliance on inorganic fertilizers with less or no use of organic fertilizers has impaired the productivity of soils worldwide. Therefore, the present study was conducted to quantify the effects of integrated nutrient management on rice yield, nutrient use efficiency, soil fertility, and carbon (C) sequestration in cultivated land. The experiment was designed with seven treatments comprising of a zero input control, recommended inorganic fertilizers (RD), poultry manure (PM) (5 t ha−1) + 50% RD, PM (2.5 t ha−1) + 75% RD, vermicompost (VC) (5 t ha−1) + 50% RD, VC (2.5 t ha−1) + 75% RD, and farmers’ practice (FP) with three replications that were laid out in a randomized complete block design. The highest grain yield (6.16–6.27 t ha−1) was attained when VC and PM were applied at the rate of 2.5 t ha−1 along with 75% RD. Uptake of nutrients and their subsequent use efficiencies appeared higher and satisfactory from the combined application of organic and inorganic fertilizers. The addition of organic fertilizer significantly influenced the organic carbon, total carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, soil pH, phosphorus, potassium, sulfur, calcium, and magnesium contents in post-harvest soil, which indicated enhancement of soil fertility. The maximum value of the organic carbon stock (18.70 t ha−1), total carbon stock (20.81 t ha−1), and organic carbon sequestration (1.75 t ha−1) was observed in poultry manure at the rate of 5 t ha−1 with 50% RD. The soil bulk density decreased slightly more than that of the control, which indicated the improvement of the physical properties of soil using organic manures. Therefore, regular nourishment of soil with organic and inorganic fertilizers might help rejuvenate the soils and ensure agricultural sustainability.

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Aromatic rice has great potential to attract rice consumer for its taste and deliciousness, and high price to boost up the economic condition of the rice grower in the developing countries. A field experiment was conducted to evaluate the morpho-physiological and biochemical attributes in relation to yield potentials of fine aromatic rice varieties in Bangladesh. Two aromatic fine rice cultivars, Ukunmadhu and Kataribough (local land races), one hybridized variety BRRIdhan32 and one mutant variety Binasail were used in the experiment. The results revealed that rice varieties BRRIdhan32 and Binasail showed the greater number of branches of panicle, grain size, grain yield and harvest index as compared to aromatic varieties. On the other hand, aromatic rice showed taller plant stature, more tiller, plant biomass and larger panicle but lower number of primary and secondary branches, grain size, yield and harvest index. The biochemical attributes namely chlorophyll and soluble protein content were higher at vegetative stage as compared to panicle initiation and flowering stages. The aromatic rice Kataribhough and Ukonmondhu contained higher amount of total free amino acid as compared to that of Binasail and BRRIdhan32. Other biochemical parameters namely nitrate reductase activity (NRA), total sugar and free amino acid contents were higher at flowering stage compared to those contained at tillering and panicle initiation stages. Physico-chemical properties of grain viz. length, breadth, L/B ratio, nitrogen (%) and protein (%) were significantly higher in fine rice as compared to aromatic rice. From the results it may be concluded that the high yielding varieties were more efficient in transfer of photosynthate to the grain i.e. economic yield and that is why BRRIdhan32 recorded the highest yield. Poor yield in Ukonmodhu and Kataribhough was due to low harvest index indicating minimum translocation of assimilates to the grains.