Plant Growth Promoting Rhizobacteria (PGPR): Impact on peanut flowering, seed physical quality, and yield determination (Arachis hypogaea L.)

• Published in: Industrial crops and products Vol. 219; p. 119024
• Main Authors: Bigatton, E.D., Castillejo, M.A., Ayoub, Baldessari, J.J., Bruno, M., Archilla, M.V., Dubini, L.E., Lucini, E., Haro, R.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: Bacillus; Flowering process; Plant hormones; Pseudomonas; Sowing date; Flowering process; Pseudomonas; Sowing date; Plant hormones; Bacillus
• ISSN: 0926-6690
• DOI: 10.1016/j.indcrop.2024.119024

Peanut seed yield is influenced by physiological and ecophysiological crop traits, with changes in reproductive parameters such as flowering time, flower number, and fertility index significantly affecting productivity. Management practices like Plant Growth-Promoting Rhizobacteria (PGPR) could enhance crop yield. PGPR can improve flowering and yield by modulating the balance of phytohormones and enhancing reproductive processes. This study assessed PGPR effects on peanut flowering dynamics, seed yield determination, and correlation with hormone levels. Two plant-level field experiments were conducted during 2019–2020 and 2020–2021, sowing two cultivars (ASEM 400 INTA and Granoleico) on four sowing dates (Oct-05, Oct-15, Nov-29, Dec-10). Three PGPR strains (Bacillus velezensis RI3 and SC6, Pseudomonas psychrophila P10), Bradyrhizobium japonicum, and control were arranged in a split-split-split-plot design, with sowing dates as main plots, cultivars as sub-plots, and PGPRs as sub-sub-plots. PGPR improved peanut flower number (FN) and flowering rate (FR) by 20 % and 50 % compared to B. japonicum and the control. B. velezensis SC6 showed the best performance (SC6 > P10 > RI3), advancing the flowering peak by 4–12 days. PGPR also increased the fertility index (FI) to 0.31 vs. 0.24 of B. japonicum and control and pod number (PN) by 53 % compared to the control. Flowering peak advancement led to larger seeds (SF≥8 mm) (∼+8 % vs. control) due to better environmental conditions (i.e., higher temperatures). Seed number (SN) increased by 94 %–113 % under PGPR treatments. Seed yield (SY) was increased (∼75 % on average) due to higher total biomass (TB) production and improved carbon allocation to seeds (harvest index; 0.33–0.36). Hormone analysis at the R5 stage under late sowing's restrictive conditions showed hormone level increases of 15 %–90 %. This study demonstrates that PGPR significantly improves peanut flowering dynamics, seed quality, and yield by affecting hormone levels and reproductive parameters, highlighting its potential as a sustainable management practice. [Display omitted] •PGPR improved peanut flower number and flowering rate by 20 % and 50 %.•PGPR (SC6 > P10 > RI3) led to a peanut flowering peak advancement of 4 – 12 days.•PGPR increased the fertility index and pod number by 29 % and 53 %, respectively.•PGPR increased the seed yield by 75 % due to a harvest seed index of 0.33 – 0.36.•Hormone profile in the late sowing date increased between 15 % and 90 %.