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Table 4 Shoot dry weight (SDW), root dry weight (RDW), N content (NC), total N accumulated in the shoots (TNS), chlorophyll content (CC), root volume (RV), culm diameter (CD), plant height (PH), and MPN (most probable number) of diazotrophic bacteria on leaves, roots and rhizosphere in a greenhouse experiment performed with hybrid maize BRS 3010 in response to different doses of inoculant, levels of N fertilization, and methods of inoculation

From: Accessing inoculation methods of maize and wheat with Azospirillum brasilense

Treatment SDW (g pl−1) RDW (g pl−1) NC (mg g−1) TNS (mg pl−1) CC (µg cm−2) Biometric measurements Bacterial MPN
RV (mL pl−1) CD (mm) PH (cm) Leaves (n° cells g−1) Roots (n° cells g−1) Rhizosphere soil (n° cells g−1)
T1: C + 75 % Na 6.67 c* 3.77 bc 14.74 abc 98.33 cde 12.99ns 19.90 abc 9.47ns 66.60 bcd 4.57 × 106 cde 1.73 × 108 e 1.55 × 106 b
T2: C + 100 % N 8.01 ab 3.96 bc 14.41 abcd 115.60 abc 13.71 20.30 abc 10.12 73.12 ab 2.92 × 106 de 4.75 × 108 bcde 5.52 × 105 b
T3: SI + 1 doseb + 75 % N 7.43 abc 3.92 bc 11.81 de 87.03 e* 12.93 18.90 bc 9.97 64.40 bcd 2.47 × 106 de 6.24 × 108 abcde 6.12 × 105 b
T4: SI +1 dose + 100 % N 7.56 abc 3.66 c 15.17 ab 113.99 abc 14.76 19.40 bc 9.93 62.10 d 1.14 × 107 bcde 6.24 × 108 abcde 2.12 × 106 b
T5: SI + 2.5 doses + 75 % N 7.71 abc 3.95 bc 14.96 ab 115.93 abc 12.33 20.40 abc 10.08 64.60 bcd 4.31 × 106 cde 6.86 × 108 abcde 5.10 × 105 b
T6: SI + 2.5 doses + 100 % N 8.02 ab 4.47 ab 14.74 abc 117.91 abc 12.99 23.30 a 10.22 66.50 bcd 1.16 × 108 b 2.83 × 108 cde 5.10 × 105 b
T7: IPF + 1 dose + 75 % N 7.29 bc 4.11 bc 15.72 ab 114.39 abc 12.29 18.70 bc 10.08 65.50 bcd 1.22 × 108 b* 5.03 × 108 abcde 3.02 × 106 b
T8: IPF + 1 dose + 100 % N 7.59 abc 3.93 bc 15.96 ab 123.21 a 13.72 19.10 bc 10.58 70.75 abcd 2.70 × 107 bcd 4.58 × 108 abcde 2.52 × 107 a*
T9: IPF + 2.5 doses + 75 % N 8.16 ab 4.07 bc 11.33 e* 91.93 de 12.18 19.60 bc 10.22 65.70 bcd 2.18 × 107 bcd 1.25 × 109 a* 1.52 × 106 b
T10: IPF + 2.5 doses + 100 % N 7.57 abc 3.88 bc 14.66 abcd 109.79 abcd 13.30 18.40 bc 10.07 69.80 abcd 2.40 × 109 a* 3.28 × 108 bcde 8.48 × 107 b
T11: ILS + 1 dose + 75 % N 7.30 abc 3.92 bc 13.62 abcde 99.49 cde 12.28 20.30 abc 10.25 68.80 abcd 2.05 × 109 a* 2.37 × 108 de 1.03 × 106 b
T12: ILS + 1 dose + 100 % N 7.39 abc 4.17 bc 13.48 abcde 98.64 cde 13.38 20.20 abc 10.58 62.87 cd 7.38 × 107 bc 1.02 × 10 abc 4.65 × 106 ab
T13: ILS + 2.5 doses + 75 %N 7.22 bc 4.41 abc 13.47 abcde 96.92 cde 12.38 21.30 ab 10.07 70.20 abcd 7.50 × 106 bcde 9.18 × 108 abcd 1.54 × 106 b
T14: ILS + 2.5 doses + 100 % N 8.13 ab 5.00 a* 13.07 bcde 106.06 abcde 12.63 21.00 abc 10.30 72.80 cd 1.12 × 106 de 7.33 × 108 abcde 3.04 × 106 b
T15: ISS + 1 dose + 75 % N 7.52 abc 3.60 c 13.14 abcde 98.30 cde 13.29 18.10 bc 9.84 68.70abcd 4.07 × 106 cde 4.84 × 108 cde 1.34 × 106 b
T16: ISS + 1 dose + 100 % N 7.92 abc 4.38 abc 16.05 a 126.731 a 13.97 20.50 abc 10.07 75.70a 1.10 × 106 de 9.94 × 108 abc 1.40 × 106 b
T17: ISS + 2.5 doses + 75 % N 8.50 a 4.47 ab 11.95 cde 101.15 bcde 11.80 21.30 ab 10.43 73.10 ab 1.11 × 106 de 3.66 × 108 cde 1.50 × 106 b
T18: ISS + 2.5 doses + 100 % N 7.72 abc 3.88 bc 15.71 ab 121.13 ab 13.91 17.70 c 10.21 71.40 abc 6.25 × 105 e 1.14 × 109 ab 1.65 × 106 b
p value 0.0058 0.015 <0.0001 <0.0001 0.5525 0.00492 0.6696 0.0127 <0.0001 0.0192 0.0002
CV (%) 8.08 12.81 10.57 10.06 13.92 12.02 6.38 10.6 11.2 6.65 9.24
  1. Parameters determined 52 days after seedling emergence
  2. Means (five replicates) followed by the same letter on the same column are not significantly different from one another according to Duncan’s test (p ≤ 0.05), whereas means followed by * are significantly different from treatment 2 (T2) according to Dunnet’s test (p ≤ 0.05). ns not significant
  3. C non-inoculated control, SI standard seed inoculation, IPF inoculation at planting in the furrow, ILS inoculation by leaf spray at the V2.5 stage, ISS inoculation by soil spray at the V2.5 stage
  4. aN: 75 % (90 kg ha−1) and 100 % (120 kg ha−1), split in equal amounts every 8 days
  5. bInoculant dose:1× (1.0 × 105 cells seeds−1 or 1.0 × 105 cells plant−1)