Seed priming with boron and Bacillus sp. MN54 inoculation improves productivity and grain boron concentration of chickpea.

Context: The production of chickpea (Cicer arietinum L.) is negatively affected by boron (B) deficiency. In Pakistan, the crop grown under B deficiency produces grains with low B concentration. Application of B-tolerant bacteria (BTB) is a promising option to improve B supply to plants grown under B deficiency. Aims: This study was focused on determining the appropriate concentration of B for seed priming, and its effects with BTB inoculation on growth, productivity and grain B concentration of chickpea. Methods: Chickpea seeds were primed in aerated solutions of B concentrations in the range 0.01–0.5% (w/v), with hydroprimed and dry seeds as controls. Concentrations >0.1% proved toxic and seeds failed to germinate. Hence, B was further diluted to concentrations in the range 0.0001–0.1%. Pots containing chickpea seeds were divided into two sets having all B treatments. One set was inoculated with BTB (5 mL per pot of pure Bacillus sp. MN54 culture at 10 9 cfu mL−1); the other set was not inoculated. Key results: Seed priming with B along with BTB inoculation improved stand establishment, growth, nodulation, yield and grain B concentration of chickpea. Seed priming treatments with B at 0.001% and 0.0001% along with BTB inoculation were most effective for improving stand establishment, seedling growth and grain yield, whereas 0.1% B was more effective for improving grain B concentration. Conclusions: Seed priming with 0.001% B along with inoculation of Bacillus sp. MN54 improved seed germination, nodulation, yield and grain B concentration of chickpea under B-deficiency conditions. Implications: Seed inoculation with BTB i.e., Bacillus sp. MN54 coupled with seed priming in 0.001% B solution is a viable option to improve yield and grain B concentration of chickpea grown on B-deficient soils. Boron (B) deficiency is the leading constraint to chickpea productivity in Pakistan. Results of this study elucidated that B seed priming at lower rates (0.001% and 0.0001%) along with seed inoculation with B-tolerant bacteria (Bacillus sp. MN54) improved the productivity and grain-B biofortification of chickpea. Higher levels of B seed priming (>0.1% B solution) proved toxic, with no germination recorded. [ABSTRACT FROM AUTHOR]