Table 1.
Effect of drought stress and PGPR application on relative growth rate and dry matter production in two potato cultivars.
| Cultivars | PGPR treatments | Drought treatments | Relative growth rate (mg g−1 day−1) | Dry matter (g/pot) | Pre-drought limitation (%) | ||
|---|---|---|---|---|---|---|---|
| During stress (tuber initiation) | Tuber initiation-tuber bulking | Tuber bulking-maturation | |||||
| Santae | With PGPR | CK | 28.5 ± 2 a | 23.4 ± 1.3 bc | 18.5 ± 2 a | 65.3 ± 2.6 a | 0.00 |
| MS | 16.5 ± 1 c | 27.5 ± 1.1 a | 16.5 ± 1 b | 50.5 ± 2.2 c | 22.7 ± 2.2 c | ||
| SS | 03.3 ± 3 e | 12.7 ± .3 d | 11.3 ± 3 d | 34.6 ± 2.4 e | 45.0 ± 2.4 b | ||
| Without PGPR | CK | 27.6 ± 1.2 ab | 21.3 ± .5 c | 16.6 ± 1.2 b | 62.3 ± 2 ab | 0.00 | |
| MS | 12.6 ± 1.5 d | 22.3 ± 1 c | 12.6 ± 1.5 c | 44.5 ± 3 d | 24.5 ± 3 d | ||
| SS | 1.3 ± 0.5 f. | 10.3 ± .2 e | 8.3 ± 0.5 e | 31.6 ± 1.2 f. | 50.6 ± 1.2 a | ||
| PRI-Red | With PGPR | CK | 31.4 ± 1 a | 24.4 ± 1.2 a | 19.4 ± 1 a | 64.5 ± 1 a | 0.00 |
| MS | 12.5 ± 2 c | 23.3 ± 1.2 ab | 15.5 ± 2 c | 49.6 ± 2 c | 25.6 ± 2 c | ||
| SS | 1.5 ± 0.5 e | 9.2 ± 1.5 c | 7.5 ± 0.5 e | 25.3 ± 1 e | 60.3 ± 1 b | ||
| Without PGPR | CK | 30.5 ± 1 ab | 22.2 ± 1 b | 17.5 ± 1 b | 60.4 ± 3 b | 0.00 | |
| MS | 10.6 ± 0.6 d | 24.1 ± 1 a | 12.6 ± 0.6 d | 42 ± 2.6 d | 30 ± 2.6 d | ||
| SS | 1.0 ± 0.5 f | 7.5 ± .2 d | 5.5 ± 0.5 f. | 22 ± 1.4 f. | 63.3 ± 1.4 a | ||
Plants of both genotypes were treated with 100 g of bio-fertilizer at 10 days after germination and exposed to different soil relative water contents (SRWC), including 80 ± 5% (well watered; CK), 60 ± 5% (moderate stress; MS) and 40 ± 5% SRWC (severe stress; SS) for 7 days at tuber initiation stage (30 days after germination). Lowercase letter after each data in the column indicates significant difference at P < 0.05 between the treatments for each cultivar separately.