Impact of plant genotype and nitrogen level on rice growth response to inoculation with Azospirillum sp. strain B510 under paddy field conditions

Figures & data

Table 1 Rice plant materials used this study

Cultivar name	Origin	Variety/group
Nipponbare	Japan	Japonica
Koshihikari	Japan	Japonica
Fukkurinko	Japan	Japonica
Nanatsuboshi	Japan	Japonica
Akage	Japan	Japonica
Sekiyama	Japan	Japonica
Habataki	Japan	Japonica
Dianyu 1	China	Japonica
Khao Nam Jen	Laos	Japonica
Khau Mac Kho	Vietnam	Japonica
Tupa 121–3	Bangladesh	Indica-1
Kasalath	India	Indica-1
Muha	Indonesia	Indica-1
Basilanon	Philippines	Indica-1
Bei Khe	Cambodia	Indica-2
Ryou Suisan Koumai	China	Indica-2
Deng Pao Zhai	China	Indica-2
Naba	India	Indica-2
Milyang 23	Korea	Indica-2
Bleiyo	Tailand	Indica-2

Table 2 Characteristics of field soils

Field	pH (H2O)	Total C content (%)	Total N content (%)	Truog phosphorous content (mg P2O5 kg^−1)
Standard nitrogen	5.2	4.3	0.10	74.0
Low nitrogen	5.5	3.3	0.08	62.5

Figure 1 Inoculation effect index (IEI, %) for tiller number (a–d) and shoot length (e–h) of rice plants. IEI = (tiller number or shoot length of rice plants inoculated with B510)/(tiller number or shoot length of rice plants without inoculation) × 100. IEI for tiller number (a) 37 days after transplanting (DAT) under standard nitrogen (SN) conditions; (b) 37 DAT under low nitrogen (LN) conditions; (c) 58 DAT, SN; (d) 58 DAT, LN. IEI for shoot length (e) 37 DAT, SN; (f) 37 DAT, LN; (g) 58 DAT, SN; (h) 58 DAT, LN. White and black arrowheads respectively signify that means (n = 9) of tiller number or shoot length of rice plants inoculated with B510 were significantly higher and lower than those of rice plants without inoculation (P < 0.05, t-test). AK, Akage; BA, Basilanon; BE, Bei Khe; BL, Bleiyo; DE, Deng Pao Zhai; DI, Dianyu 1; FU, Fukkurinko; HA, Habataki; KA, Kasalath; KM, Khau Mac Kho; KN, Khao Nam Jen; KO, Koshihikari; MI, Milyang 23; MU, Muha; NB, Naba; NI, Nipponbare; NN, Nanatsuboshi; RY, Ryou Suisan Koumai; SE, Sekiyama; TU, Tupa 121-3.

Table 3 Effects of Azospirillum sp. B510 inoculation on tiller number of rice plants

Variety group/cultivar name	37 DAT				58 DAT
	Standard nitrogen		Low nitrogen		Standard nitrogen		Low nitrogen
	Control	Inoculated	Control	Inoculated	Control	Inoculated	Control	Inoculated
Japonica
Nipponbare	20.9 ± 1.9^†	17.2 ± 1.4**	15.2 ± 2.2	15.4 ± 2.4	31.4 ± 2.8	28.4 ± 2.7*	20.9 ± 2.6	25.1 ± 2.7**
Koshihikari	20.6 ± 2.4	15.0 ± 3.0**	11.8 ± 1.6	9.6 ± 1.4**	26.6 ± 2.2	24.1 ± 3.4	18.3 ± 1.2	18.7 ± 1.8
Fukkurinko	23.3 ± 3.1	17.8 ± 1.8**	13.6 ± 3.4	14.2 ± 2.4	29.3 ± 3.0	22.6 ± 1.7**	15.6 ± 3.2	18.7 ± 3.4
Nanatsuboshi	17.9 ± 1.4	13.7 ± 3.3**	12.9 ± 2.8	11.0 ± 2.2	21.8 ± 2.8	18.4 ± 4.2	15.3 ± 2.4	14.9 ± 0.8
Akage	11.9 ± 2.3	13.3 ± 1.7	11.4 ± 2.3	12.0 ± 1.7	16.1 ± 2.0	15.6 ± 1.7	12.3 ± 2.2	14.0 ± 2.1
Sekiyama	9.8 ± 1.3	11.3 ± 1.3*	11.6 ± 1.5	9.2 ± 1.2**	12.8 ± 1.6	14.2 ± 1.1	11.8 ± 1.7	10.4 ± 0.7*
Habataki	9.0 ± 1.9	7.6 ± 1.9	10.5 ± 2.5	10.0 ± 1.7	23.3 ± 1.9	19.6 ± 2.0**	15.7 ± 2.4	15.4 ± 1.2
Dianyu 1	17.6 ± 3.1	17.1 ± 2.0	10.6 ± 1.9	10.3 ± 1.9	25.6 ± 1.7	24.4 ± 2.5	18.3 ± 1.4	18.7 ± 1.9
Khao Nam Jen	8.0 ± 1.1	9.3 ± 2.3	8.5 ± 1.6	8.1 ± 1.1	11.6 ± 2.0	13.3 ± 2.5	10.3 ± 1.9	9.8 ± 2.0
Khau Mac Kho	7.9 ± 1.5	9.6 ± 0.9*	4.6 ± 0.7	5.4 ± 1.0*	11.6 ± 1.2	11.9 ± 1.6	7.6 ± 1.3	7.7 ± 1.9
Indica-1
Tupa 121-3	15.0 ± 4.0	14.9 ± 4.8	9.6 ± 1.9	7.7 ± 1.7*	25.4 ± 1.7	22.6 ± 2.7*	20.9 ± 1.4	18.3 ± 2.5*
Kasalath	17.9 ± 2.8	16.0 ± 3.0	10.1 ± 1.1	10.6 ± 2.2	31.2 ± 3.6	26.3 ± 2.3**	21.3 ± 2.1	22.4 ± 3.2
Muha	12.2 ± 1.8	14.0 ± 1.7*	13.2 ± 2.3	17.6 ± 4.0*	28.0 ± 4.0	26.7 ± 3.1	20.6 ± 3.4	20.4 ± 2.0
Basilanon	15.8 ± 2.7	14.2 ± 3.2	9.4 ± 1.8	9.9 ± 1.7	40.0 ± 4.9	39.9 ± 6.3	29.0 ± 3.1	27.3 ± 2.5
Indica-2
Bei Khe	13.4 ± 3.0	18.0 ± 3.9*	16.6 ± 2.3	16.7 ± 4.6	32.4 ± 2.6	27.4 ± 3.8**	28.4 ± 2.7	26.3 ± 3.6
Ryou Suisan Koumai	14.2 ± 3.0	19.2 ± 3.1**	14.3 ± 1.5	17.6 ± 2.7**	29.6 ± 3.6	29.2 ± 3.2	21.3 ± 2.3	23.2 ± 1.9
Deng Pao Zhai	13.7 ± 2.1	19.2 ± 1.4**	15.6 ± 2.9	17.8 ± 3.9	35.0 ± 3.2	37.2 ± 3.1	27.8 ± 3.8	28.0 ± 3.2
Naba	17.2 ± 2.3	20.4 ± 3.4*	14.7 ± 3.3	17.6 ± 1.9*	36.1 ± 5.3	31.4 ± 3.4*	27.0 ± 3.8	25.7 ± 2.0
Milyang 23	13.0 ± 2.8	15.8 ± 1.9*	8.6 ± 0.9	10.1 ± 1.6	26.4 ± 2.9	28.1 ± 2.2	19.4 ± 2.5	18.8 ± 3.2
Bleiyo	8.8 ± 3.7	10.2 ± 1.0	10.0 ± 1.7	9.8 ± 2.5	22.3 ± 2.8	21.8 ± 2.0	19.1 ± 2.5	17.2 ± 2.0
*P < 0.05; **P < 0.01 for comparison between control and inoculated samples. ^†Mean ± SD (n = 9). DAT, days after transplanting.

Table 4 Efects of Azospirillum sp. B510 inoculation on shoot length of rice plants

Variety group/cultivar name	37 DAT				58 DAT
	Standard nitrogen		Low nitrogen		Standard nitrogen		Low nitrogen
	Control	Inoculated	Control	Inoculated	Control	Inoculated	Control	Inoculated
japonica
Nipponbare	41.2 ± 1.7^†	40.2 ± 2.2	41.4 ± 1.9	39.1 ± 1.0**	65.8 ± 1.9	63.8 ± 1.8*	66.1 ± 2.7	64.3 ± 1.8
Koshihikari	49.1 ± 1.4	47.2 ± 3.1	47.8 ± 1.1	45.0 ± 2.6**	78.6 ± 2.6	78.9 ± 2.6	76.3 ± 2.0	75.5 ± 2.8
Fukkurinko	57.3 ± 2.6	54.1 ± 2.9*	51.6 ± 2.1	51.4 ± 4.0	82.0 ± 3.3	81.0 ± 1.7	75.7 ± 2.6	76.6 ± 4.7
Nanatsuboshi	57.8 ± 2.7	55.7 ± 1.7	54.8 ± 2.2	51.7 ± 4.1	83.0 ± 2.7	82.7 ± 5.0	80.1 ± 1.0	80.6 ± 2.8
Akage	66.6 ± 1.9	66.9 ± 4.0	68.0 ± 4.3	67.4 ± 6.6	93.0 ± 5.2	91.7 ± 4.3	90.2 ± 5.0	89.8 ± 3.0
Sekiyama	54.2 ± 3.0	55.1 ± 2.3	60.7 ± 2.0	58.3 ± 3.7	96.7 ± 2.4	96.2 ± 2.6	90.8 ± 2.7	91.2 ± 4.3
Habataki	50.9 ± 1.3	51.0 ± 1.8	55.4 ± 1.5	51.2 ± 1.0**	70.7 ± 1.6	69.3 ± 2.1	65.5 ± 2.0	65.9 ± 1.7
Dianyu 1	45.2 ± 1.9	45.3 ± 1.2	43.1 ± 1.4	43.3 ± 1.3	75.8 ± 2.0	74.9 ± 4.2	74.5 ± 3.9	75.4 ± 1.7
Khao Nam Jen	59.8 ± 2.8	55.2 ± 4.9*	56.1 ± 3.0	57.4 ± 2.5	100.7 ± 1.8	92.8 ± 2.0**	88.2 ± 3.0	88.9 ± 3.7
Khau Mac Kho	50.3 ± 3.9	50.2 ± 3.2	46.0 ± 2.8	49.4 ± 3.6*	96.1 ± 1.0	93.3 ± 2.1	87.1 ± 4.4	87.5 ± 3.0
Indica-1
Tupa 121-3	42.8 ± 1.4	41.1 ± 1.7	37.9 ± 0.9	38.7 ± 1.2	71.8 ± 2.2	69.3 ± 1.7*	64.4 ± 1.4	62.7 ± 1.0**
Kasalath	53.7 ± 3.7	51.6 ± 2.3	48.6 ± 2.4	47.6 ± 3.4	81.6 ± 2.9	80.4 ± 1.4	74.0 ± 2.1	76.7 ± 2.8*
Muha	43.3 ± 0.8	43.2 ± 1.3	44.2 ± 1.2	45.5 ± 1.4*	71.0 ± 2.6	71.6 ± 2.0	67.7 ± 1.8	69.1 ± 0.8
Basilanon	45.2 ± 2.6	42.7 ± 1.2*	41.6 ± 1.1	43.7 ± 2.2*	64.1 ± 3.2	57.7 ± 1.5**	56.1 ± 2.2	56.7 ± 2.0
Indica-2
Bei Khe	51.9 ± 2.5	53.6 ± 5.5	50.4 ± 2.3	53.3 ± 2.0*	80.6 ± 2.8	75.0 ± 3.2**	70.7 ± 2.7	69.1 ± 1.5
Ryou Suisan Koumai	61.2 ± 2.1	65.1 ± 1.6**	60.4 ± 2.8	62.4 ± 3.0	106.7 ± 3.6	07.6 ± 2.7	98.1 ± 4.0	96.8 ± 2.8
Deng Pao Zhai	57.6 ± 2.3	57.8 ± 2.7	53.3 ± 3.2	56.2 ± 2.7	89.1 ± 1.6	86.4 ± 1.4**	77.7 ± 2.5	77.3 ± 1.9
Naba	49.5 ± 2.5	46.7 ± 3.5	44.0 ± 4.1	47.1 ± 1.7	72.9 ± 2.6	71.8 ± 6.1	64.6 ± 3.0	66.6 ± 1.6
Milyang 23	42.1 ± 2.8	38.9 ± 2.0*	37.3 ± 1.1	37.7 ± 1.2	61.0 ± 1.4	54.9 ± 2.4**	55.0 ± 1.9	53.6 ± 1.6
Bleiyo	50.8 ± 3.8	55.6 ± 2.4**	54.1 ± 2.4	53.7 ± 2.5	83.3 ± 2.6	81.6 ± 4.4	75.7 ± 1.7	74.7 ± 2.1
*P < 0.05; **P < 0.01 for comparison between control and inoculated samples. ^†Mean ± SD (n = 9). DAT, days after transplanting.

Figure 2 Correlation analysis between the inoculation effect index (IEI, %) under standard nitrogen (SN) and low nitrogen (LN) field conditions and the nitrogen effect index (NEI, %), for tiller number and shoot length in each genotype of rice plant. (a) IEI and NEI for tiller number 37 days after transplanting (DAT) in the SN field, (b) 37 DAT in the LN field, (c) 58 DAT in the SN field, (d) 58 DAT in the LN field. (e) IEI and NEI for shoot length 37 DAT in the SN field, (f) 37 DAT in the LN field, (g) 58 DAT in the SN field, (h) 58 DAT in the LN field. In (d), the correlation coefficient in parentheses was calculated, excluding Nipponbare. IEI (%) = (tiller number of rice plants inoculated with B510)/(tiller number of rice plants without inoculation) × 100. NEI (%) = (tiller number of rice plants in SN field)/(tiller number in LN field) × 100. *P < 0.01; **P < 0.05.