Unravelling the role of indigenous PGPB in corm development and mineral acquisition of Freesia hybrida: a multivariate perspective

Code	Characteristics	Active components	Proportions (CFU · mL^-1)
A1	Siderophores production	Bacillus toyonensis, Lysinibacillus fusiformis	1 × 10⁷
A2	IAA production	Bacillus toyonensis, Pseudomonas putida	1 × 10⁷
A3	Phosphate solubilisation	Bacillus proteolyticus, Pseudomonas batumici	1 × 10⁷
A4	Potassium solubilisation	Pseudomonas lini, Bacillus safensis	1 × 10⁷
A5	N₂ fixer	Pseudomonas konensis, Bacillus thuringiensis	1 × 10⁷

1 CFU, colony-forming units; IAA, indole-3-acetic acid; PGPB, plant growth-promoting bacteria.

Daily mean temperature (red) and relative humidity (blue, dashed) in the greenhouse, shown with dual y-axes.

Table 2.

Soil properties by treatment.

Grp.	PH	CaCO. (%)	Salt (%)	Sat (%)	OM (%)	Ntotal (%)	P avail	Kavail	Caextr	Mgextr	Feextr	Mnextr	Znextr	Cuextr
Bad	5.53 ± 0.05 c	0.86 ± 0.11b	0.15 ±0.00 a	75.6 ± 0.57 b	3.18 ± 0.02 c	0.21 ± 0.00 b	26.4 ± 0.59 c	89.4 ± 1.22 a	2284 ± 19.68 ab	282 ± 1.80 b	33.3 ± 1.10 b	15.9 ± 0.40 b	1.91 ± 0.05 c	1.92 ± 0.07 c
C.F.	6.22 ±0.00 a	1.70 ± 0.2 a	0.04 ±0.001 c	78.6 ±0.57 a	3.65 ± 0.01b	0.23 ± 0.00 a	43.52 ±2.87 a	83.3 ± 1.85 b	2184 ± 77.86 b	233 ± 7.90 c	33.7 ± 0.80 b	8.10 ±0.21 c	2.64 ± 0.08 b	2.21 ± 0.07 b
Cont	5.83 ± 0.05 b	0.83 ± 0.05 b	0.10 ± 0.0005 b	77.6 ± 1.154 a	4.25 ± 0.025 a	0.20 ± 0.00 c	39.7 ± 1.086 b	73.5 ± 1.80 c	2341 ± 37.06 a	316 ± 7.29 a	37.4 ± 0.75 a	15.4 ± 0.22 b	2.79 ± 0.05 a	3.87 ±0.12 a
LSD	0.09	0.27	0.00	1.63	0.04	0.00	3.61	3.30	102.05	12.59	1.80	0.59	0.13	0.19
%CV	0.80	12.12	0.11	1.06	0.54	1.22	4.93	2.01	2.25	2.27	2.59	2.16	2.68	3.56

1 C.F., chemical fertiliser; CV, coefficient of variation (%); LSD, least significant difference; OM, organic matter atp < 0.05.

Table 3.

Effects of PGPB consortia and chemical fertilisation on bulb development and reproductive traits in F. hybrida.

Grp.	CDW (g · parcel^-1)	Net Δ CFW (g · parcel^-1)	Net Δ CD (mm · parcel^-1)	NC (number · parcel^-1)	LA (cm2)	CHL
A1	3.47 ± 0.26 c	8.87 ± 1.33 b	16.13 ± 0.67 c	3.13 ± 0.34 a	85.42 ± 10.29 bc	59.58 ± 6.52 a
A2	4.20 ± 0.42 a	10.46 ± 0.36 a	21.15 ± 1.58 a	2.53 ± 0.50 bc	91.11 ± 9.65 a	60.35 ± 5.65 a
A3	3.15 ± 0.51 d	9.21 ± 1.33 b	15.04 ± 1.24 d	2.17 ± 0.38 d	86.59 ± 11.81 bc	58.03 ± 7.12 ab
A4	3.94 ± 0.49 b	10.51 ± 0.31 a	17.35 ± 1.59 b	2.97 ± 0.14 a	87.04 ± 9.90 ab	59.64 ± 6.08 a
A5	3.27 ± 0.50 d	8.37 ± 1.25 c	15.09 ± 1.88 d	2.62 ± 0.49 b	85.09 ± 9.95 bc	55.26 ± 8.11 b
C.F.	3.21 ± 0.48 d	9.03 ± 1.27 b	14.10 ± 1.67 e	2.40 ± 0.49 c	84.90 ± 10.04 bc	56.32 ± 4.22 b
C	3.28 ± 0.54 d	8.30 ± 0.97 c	14.37 ± 2.01 e	2.00 ± 0.21 e	82.55 ± 9.56 c	52.19 ± 8.37 c
LSD	0.29	0.77	0.66	0.16	4.23	4.92
%CV	12.33	11.52	9.77	15.38	11.83	11.72

1 A1–A5: PGPR treatments.

1 C, control; C.F., chemical fertiliser; CDW, corm dry weight (g · parcel^-1); CFW, corm fresh weight; CHL, chlorophyll content (SPAD units; chlorophyll index); CV, coefficient of variation (%); LA, leaf area (cm²); LSD, least significant difference at p < 0.05; NC, number of cormlets (number · parcel^-1); Net Δ CD, net change in corm diameter (mm · parcel^-1); Net Δ CFW, net change in corm fresh weight (g · parcel^-1); PGPB, plant growth-promoting bacteria; PGPR, plant growth-promoting rhizobacteria.

Representative corms of *F. hybrida* under PGPR treatments (A1–A5), fertiliser (C.F.) and control (C). Within each panel: PGPR (left), fertiliser (middle), control (right). C.F., chemical fertilizer; PGPR, plant growth-promoting rhizobacteria.

Table 4.

Bulb content analyses after harvest.

Grp.	N	P	K	Ca	Mg	Fe	Mn	Zn	Cu
A1	1.85 ±0.011 e	0.19 ± 0.03 b	0.63 ± 0.032 e	0.28 ± 0.005 b	0.12 ± 0.005 d	1362 ± 33.45 e	27.4 ± 1.153 cd	10.03 ± 1.87 c	4.23 ± 0.28 e
A2	2.10 ± 0.015 b	0.24 ±0.00 a	0.76 ± 0.015 b	0.32 ±0.005 a	0.25 ±0.005 a	4660 ±61.46 a	83.53 ±2.122 a	18.36 ±0.28 a	11.93 ±0.11 a
A3	1.93 ± 0.017 d	0.14 ± 0.00 d	0.64 ± 0.05 de	0.27 ± 0.005 b	0.10 ±0.01 e	394 ± 20.54 f	26.1 ± 19.52 de	4.80 ±0.2 e	3.73 ±0.51 f
A4	2.35 ±0.005 a	0.19 ± 0.00 b	0.82 ±0.005 a	0.23 ± 0.005 c	0.15 ± 0.005 c	2106 ± 24.2 c	39.36 ± 1.001 c	10.46 ± 0.50 c	5.73 ± 0.15 c
A5	1.80 ±0.011 f	0.20 ± 0.05 b	0.66 ±0.01 d	0.22 ±0.001 d	0.10 ± 0.00 e	358 ± 17.95 f	13.2 ± 0.66 e	7.53 ± 1.10 d	4.86 ± 0.25 d
C.F.	1.71 ± 0.015 g	0.16 ±0.05 cd	0.59 ± 0.00 f	0.21 ±0.01 d	0.12 ± 0.005 d	1546 ± 61.20 d	30.6 ± 1.17 cd	5.66 ± 0.68 e	4.16 ± 0.15 ef
C.	1.98 ±0.01 c	0.18 ±0.01 be	0.72 ± 0.005 c	0.21 ±0.00 d	0.18 ± 0.005 b	3307 ± 94.90 b	57.53 ± 2.35 b	12.9 ± 0.55 b	7.46 ± 0.25 b
LSD	0.02	0.01	0.01	0.01	0.01	64.5	13.16	1.135	0.48
%CV	0.66	7.87	2.18	2.46	4.14	2.65	18.94	9.18	4.59

1 Al–A5: PGPR treatments.

1 C, control; C.F., chemical fertiliser; Ca, calcium; Cu, copper; CV, coefficient of variation (%); Fe, iron; K, potassium; LSD, least significant difference (p < 0.05); Mg, magnesium; Mn, manganese; N, nitrogen; P, phosphorus; PGPR, plant growth-promoting rhizobacteria; Zn, zinc.

PCA of morphophysiological and nutritional traits of *F. hybrida*. PCA, principal component analysis.

Table 5.

PCA loadings of morphophysiological and nutritional traits in F. hybrida.

Contribution of the observations (%)
	F1	F2	F3	F4	F5
A1	0.325	14.725	16.077	0.000	12.147
A2	63.360	2.646	2.755	7.090	3.387
A3	7.720	5.919	3.687	54.765	13.054
A4	5.723	23.365	20.972	27.441	7.961
A5	9.469	0.512	39.624	8.856	7.101
C	0.076	49.967	3.043	1.411	9.453
C.F.	13.327	2.865	13.841	0.437	46.897

1 A1-A5: PGPR treatments.

1 C, control; C.F., Chemical fertiliser; F1-F5, first to fifth principal components derived from PCA analysis; PCA, principal component analysis; PGPR, plant growth-promoting rhizobacteria.

PCA biplot of fertiliser treatments based on morphophysiological and nutritional traits in *F. hybrida*. PCA, principal component analysis,

Table 6.

Pearson correlation matrix among morphophysiological and nutritional traits of F. hybrida.

Variables	CDW	NC	Net Δ CD	LA	CHL	Net Δ CFW	N	P	K	Ca	Mg	Fe	Mn	Zn	Cu
CDW	1	0.943	0.439	0.823	0.699	0.861	0.576	0.795	0.780	0.605	0.810	0.715	0.724	0.796	0.758
NC	0.943	1	0.339	0.930	0.730	0.801	0.455	0.807	0.623	0.810	0.796	0.674	0.710	0.793	0.803
Net Δ CD	0.439	0.339	1	0.130	0.438	0.360	0.209	0.372	0.171	0.234	-0.045	-0.130	-0.157	0.079	-0.142
LA	0.823	0.930	0.130	1	0.810	0.718	0.371	0.670	0.651	0.829	0.730	0.593	0.644	0.734	0.774
Chl	0.699	0.730	0.438	0.810	1	0.601	0.439	0.468	0.619	0.736	0.500	0.373	0.390	0.575	0.432
Net Δ CFW	0.861	0.801	0.360	0.718	0.601	1	0.817	0.407	0.663	0.541	0.567	0.471	0.492	0.444	0.484
N	0.576	0.455	0.209	0.371	0.439	0.817	1	-0.001	0.458	0.325	0.439	0.433	0.425	0.254	0.234
P	0.795	0.807	0.372	0.670	0.468	0.407	-0.001	1	0.543	0.504	0.744	0.661	0.670	0.854	0.802
K	0.780	0.623	0.171	0.651	0.619	0.663	0.458	0.543	1	0.177	0.664	0.602	0.591	0.658	0.610
Ca	0.605	0.810	0.234	0.829	0.736	0.541	0.325	0.504	0.177	1	0.530	0.405	0.462	0.545	0.550
Mg	0.810	0.796	-0.045	0.730	0.500	0.567	0.439	0.744	0.664	0.530	1	0.982	0.988	0.959	0.960
Fe	0.715	0.674	-0.130	0.593	0.373	0.471	0.433	0.661	0.602	0.405	0.982	1	0.996	0.924	0.920
Mn	0.724	0.710	-0.157	0.644	0.390	0.492	0.425	0.670	0.591	0.462	0.988	0.996	1	0.926	0.944
Zn	0.796	0.793	0.079	0.734	0.575	0.444	0.254	0.854	0.658	0.545	0.959	0.924	0.926	1	0.941
Cu	0.758	0.803	-0.142	0.774	0.432	0.484	0.234	0.802	0.610	0.550	0.960	0.920	0.944	0.941	1

1 CDW, corm dry weight; CFW, corm fresh weight; CHL, chlorophyll content (SPAD units; chlorophyll index); LA, leaf area; NC, number of cormlets. Bold values in Table 6 represent the diagonal self-correlation coefficients (r = 1.00) for each trait.

Table 7.

Variable contributions (%) to principal components (F1-F5) in F. hybrida.

	F1	F2	F3	F4	F5
CDW	9.298	2.352	0.064	3.831	0.449
NC	9.300	1.773	1.692	0.867	0.763
Net Δ CD	0.443	26.367	7.287	21.948	12.173
LA	8.212	1.165	1.591	8.995	9.854
Chl	5.358	10.412	1.478	2.892	16.346
Net Δ CFW	5.896	10.063	10.705	0.010	0.544
N	2.722	6.975	40.434	0.672	7.444
P	6.629	0.617	17.751	9.799	1.459
K	5.794	0.236	4.714	14.823	40.051
Ca	4.974	3.663	7.127	34.386	3.819
Mg	8.991	5.203	0.636	0.033	1.037
Fe	7.508	9.385	2.431	0.360	3.295
Mn	7.833	9.133	1.842	0.014	2.750
Zn	8.700	4.472	1.790	1.142	0.011
Cu	8.342	8.183	0.457	0.226	0.004

1 CDW, corm dry weight; CFW, corm fresh weight; LA, leaf area; NC, number of cormlets.

Proposed mechanisms by which *Bacillus* and *Pseudomonas* spp. enhance *F. hybrida* growth through VOCs, IAA, siderophores, phosphate solubilisation and ACC deaminase. ACC, 1-aminocyclopropane-1-carboxylate; IAA, indole-3-acetic acid; VOCs, volatile organic compounds.

References

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Articles in this issue

DOI: https://doi.org/10.2478/fhort-2025-0027 | Journal eISSN: 2083-5965 | Journal ISSN: 0867-1761

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Language: English

Page range: 417 - 432

Submitted on: Aug 30, 2025

Accepted on: Nov 20, 2025

Published on: Jan 27, 2026

Published by: Polish Society for Horticultural Sciences (PSHS)

In partnership with: Paradigm Publishing Services

Publication frequency: 2 issues per year

Keywords:

chlorophyll,

corm yield,

Freesia hybrida,

nutrient composition,

PGPB,

principal component analysis

Related subjects:

Life sciences,

Plant science

© 2026 Ümmü Özgül Karagüzel, Ergül Erkut, Sümeyye İslam, Atakan Yildiz, published by Polish Society for Horticultural Sciences (PSHS)
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Volume 37 (2025): Issue 3 (December 2025)

Unravelling the role of indigenous PGPB in corm development and mineral acquisition of Freesia hybrida: a multivariate perspective

Figures & Tables

Figure 1.

Table 1.

Figure 2.

Table 2.

Table 3.

Figure 3.

Table 4.

Figure 4.

Table 5.

Figure 5.

Table 6.

Table 7.

Figure 6.

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