Table 1. Effect of seed treatment with 8 bacterial isolates on the agronomic characteristics of a susceptible maize hybrid (H511) in screenhouse (mean ±std error).
|
Bacterial treatments* |
Plant height (cm) |
Root dry weight (g) |
Stover dry weight (g) |
Number of leaves |
Striga fresh weight (g) |
|
Uninoculated control |
65.3±1.8 |
3.6±0.2 |
6.4±0.8 |
7.7±0.1 |
1.5±0.4 |
|
8MR5 |
67.8±1.8 |
4.0±0.4 |
6.2±0.5 |
7.9±0.1 |
1.8±0.7 |
|
4MKS8 |
68.6±1.7 |
3.9±0.4 |
6.4±0.6 |
8.2±0.1 |
2.0±0.6 |
|
10MKR7 |
67.6±1.2 |
3.9±0.2 |
7.5±0.7 |
7.9±0.2 |
0.9±0.3 |
|
8MR5+4MKS8 |
66.5±2.3 |
4.1±0.5 |
6.8±0.7 |
7.9±0.2 |
1.6±0.5 |
|
8MR5+10MKR7 |
63.5±3.6 |
3.8±0.3 |
7.0±0.7 |
7.9±0.2 |
1.7±0.7 |
|
4MKS8+10MKR7 |
69.6±1.7 |
4.4±0.3 |
7.6±0.6 |
8.0±0.1 |
1.2±0.5 |
|
8MR5+4MKS8+10MKR7 |
69.6±2.1 |
4.4±0.5 |
8.1±1.0 |
8.1±0.1 |
2.3±0.8 |
|
|
|
|
|
|
|
|
LSD (0.05) |
2.98 |
0.45 |
0.99 |
0.19 |
0.72 |
*8MR5 = E. sakazakii, 4MKS8 = Pseudomonas sp., 10MKR7 = K. oxytoca
Studies were conducted on screenhouse benches at Kenya Sugar Research Foundation from January to June 2001. Clean Striga free pots (10 x 10 x 14 cm) containing approximately 1kg soil were filled with the experimental soil. S. hermonthica collected from Kibos during the long rains of year 2000, was used to conduct the experiment. The experimental soil was infested with S. hermonthica at a rate of approximately 1000 seeds/pot and left to precondition for 14 days. Bacterial suspensions (1.5ml of 1.4 x 106 cfu ml-1) were inoculated into maize planting holes as follows: (1) no bacterial cells, (2) 8MR5 only, (3) 4MKS8 only, (4) 10MKR7 only, (5) 8MR5 + 4MKS8, (6) 8MR5 + 10MKR7, (7) 4MKS8 + 10MKR7, and (8) 8MR5 + 4MKS8 + 10MKR7. Maize seed were sown three to a pot at a depth of 1.5 cm and thinned to one plant per pot at 7 days after planting. Pots were watered twice daily with tap water within the retention capacity of the pot. If soils are very dry introduced bacteria die rapidly (Chen and Alexander, 1973; Moffett et al., 1983). The potted soils were re-inoculated consecutively for the first 3 weeks on a weekly basis with 1.5ml of 1.4 x 106 cfu ml-1 bacterial inoculum, except for those pots that served as the control. The factorial experiment was laid out in completely randomized design (CRD) and repeated four times with five replicates per treatment on each occasion. Data were collected on plant height, root dry weight, stover dry weight (above-ground portion of seedling), number of leaves and Striga fresh weight.