Soil-Applied Boron Combined with Boron-Tolerant Bacteria (Bacillus sp. MN54) Improve Root Proliferation and Nodulation, Yield and Agronomic Grain Biofortification of Chickpea (Cicer arietinum L.)

Abstract

Chickpea is widely cultivated on calcareous sandy soils in arid and semi-arid regions of Pakistan; however, widespread boron (B) deficiencies in these soils significantly decreases its productivity. Soil application of B could improve chickpea yield and grain-B concentration. However, optimizing suitable B level is necessary due to a narrow deficiency and toxicity range of B. Nonetheless, the co-application of B-tolerant bacteria (BTB) and synthetic B fertilizer could be helpful in obtaining higher chickpea yields and grain-B concentration. Therefore, this study optimized the level of soil applied B along with BTB, (i.e., Bacillus sp. MN54) to improve growth, yield and grain-B concentrations of chickpea. The B concentrations included in the study were 0.00 (control), 0.25, 0.50, 0.75 and 1.00 mg B kg−1 soil combined with or without Bacillus sp. MN54 inoculation. Soil application of B significantly improved root system, nodulation, yield and grain-B concentration, and Bacillus sp. MN54 inoculation further improved these traits. Moreover, B application at a lower dose (0.25 mg B kg−1 soil) with BTB inoculation recorded the highest improvements in root system (longer roots with more roots’ proliferation), growth, nodulation and grain yield. However, the highest grain-B concentration was recorded under a higher B level (0.75 mg B kg−1 soil) included in the study. Soil application of 0.25 mg B kg−1 with Bacillus sp. MN54 inoculation improved growth and yield-related traits, especially nodule population (81%), number of pods plant−1 (38%), number of grains plant−1 (65%) and grain yield (47%) compared with control treatment. However, the grain-B concentration was higher under the highest B level (1.00 mg kg−1 soil) with Bacillus sp. MN54 inoculation. In conclusion, soil application of 0.25 mg B kg−1 with Bacillus sp. MN54 inoculation is a pragmatic option to improve the root system, nodule population, seedling growth, yield and agronomic grain-B biofortification of chickpea.

Plant growth promoting rhizobacteria improve growth and yield related attributes of chili under low nitrogen availability

“…Overall, PGPR used in the current study have potential to reduce N requirement of chili by 25% without any yield losses. Similar results for PGPR inoculation have been reported for different crops like cucumber, tomato and legumes [ 11 , 12 , 38 – 40 ]. However, these studies used only one PGPR, while we used two PGPRs indicating that both worked synergistically to improve the studied traits of chili.…”

“…Hence, the results of the present study are in the agreement with earlier findings. Similarly, PGPR are known to increase the yield of chickpea and other important crops when the seeds of these crops are inoculated with PGPRs [ 11 , 12 ].…”

“…One of the strategies to increase fertilizer use efficiency and decrease environmental degradation is the use of plant growth promoting rhizobacteria (PGPR). The PGPRs are clusters of bacteria that colonize plant roots and promote growth and yield [ 11 , 12 ]. Application of PGPRs can protect crop plants from various biotic and abiotic stresses [ 11 , 13 – 15 ].…”

“…The PGPRs are clusters of bacteria that colonize plant roots and promote growth and yield [ 11 , 12 ]. Application of PGPRs can protect crop plants from various biotic and abiotic stresses [ 11 , 13 – 15 ]. The PGPRs improve plant growth by several ways, i.e., by producing different compounds (like phytohormones, organic acids and siderophore), by fixing atmospheric N, through P solubilization and through production of biologically active constituents [ 16 – 20 ].…”

The impact of boron seed priming on seedling establishment, growth, and grain biofortification of mungbean (Vigna radiata L.) in yermosols

“…Biofortification with food essentials is vital and can be attained with different biotechnological, conventional breeding and agronomic approaches. Among these, agronomic practices are swifter than genetic biofortification [ 8 ]. Foliar feeding of crops, application in soil and invigoration of seed (coating and priming) are promising agronomic strategies for micronutrients enrichment.…”