Biotechnological potential of rhizobial metabolites to enhance the performance of Bradyrhizobium spp. and Azospirillum brasilense inoculants with soybean and maize

AMB Express

Table 4 Nodulation [nodule number (NN) and dry weight (NDW)], shoot dry weight (SDW), N concentration (NC) and total N accumulated in shoots (TNS) and grain yield of soybean cultivar BMX Potência RR inoculated or not with Bradyrhizobium japonicum CPAC 15 + B. diazoefficiens CPAC 7 and supplemented or not with genistein (5 μM) or concentrated metabolites (CM) of B. diazoefficiens USDA 110 (BD1) or Rhizobium tropici CIAT 899 (RT1). Experiments performed in two field sites in Brazil

Treatments	Bonito						Ponta Grossa
	V4		R2			Maturity	V4		R2			Maturity
	NN	NDW	SDW	NC	TNS	Yield	NN	NDW	SDW	NC	TNS	Yield
	(# pl ^–1)	(mg pl ^–1)	(g pl ^–1)	(mg N g ^–1)	(mg N pl ^–1)	(kg ha ^–1)	(# pl ^–1)	(mg pl ^–1)	(g pl ^–1)	(mg N g ^–1)	(mg N pl ^–1)	(kg ha ^–1) ^`
Non-inoculated control	10.4 ab²	43.2 b	18.4 ab	20.2 a	371 b	2701 b	45.7a	163 ab	10.4 ab	36.5 a	379 a	3166 a
Inoculated with Bradyrhizobium	15.1 ab	68.4 a	13.3 ab	20.4 a	271 c	2703 b	42.0 a	149 b	10.4 ab	35.1 ab	365 a	3191 a
Inoculated + genistein	10.7 ab	43.6 b	14.4 ab	20.2 a	290 c	2737 ab	48.7a	171 ab	12.3 a	32.0 b	393 a	3337 a
Inoculated + CM-BD1 (1 mL L^–1)¹	18.2 a	65.4 a	17.4 ab	17.6 a	306 c	2750 ab	52.5 a	206 a	12.1 a	34.6 ab	418 a	3359 a
Inoculated + CM-BD1 (0.1 mL L^–1)	16.0 a	68.1 a	19.8 ab	17.6 a	348 b	2906 a	57.8 a	212 a	11.3 ab	34.6 ab	390 a	3275 a
Inoculated + CM-RT1 (1 mL L^–1)	7.3 b	25.1 c	10.4 b	16.8 a	174 d	2641 b	45.3 a	170 ab	9.2 ab	33.4 ab	307 a	3202 a
Inoculated + CM-RT1 (0.1 mL L^–1)	13.4 ab	69.9 a	23.4 a	18.1 a	423 a	2817 ab	46.8 a	162 ab	8.9 b	35.3 ab	314 a	3253 a

¹ 0.1 and 1.0 mL L^–1 correspond to approximately 10^–9 and 10^–8 M of active compounds, respectively.
² Data represent the means of six replicates and when followed by different letters within the same column are significantly different (p ≤ 0.05, Duncan’s test).