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African Crop Science Journal
African Crop Science Society
ISSN: 1021-9730 EISSN: 2072-6589
Vol. 8, Num. 3, 2000, pp. 295-300
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African Crop Science Journal, Vol. 8. No. 3, pp. 295-300
African Crop Science Journal, Vol. 8. No. 3, pp. 295-300
ON-STATION VERIFICATION OF THE USE OF SOYBEAN TRAP-CROP FOR
THE CONTROL OF Striga IN MAIZE
I. Kureh, U.F. Chiezey and B.D. Tarfa Faculty of Agriculture, Ahmadu Bello University, PMB 1044, Zaria, Nigeria
(Received 13 July, 1999; accepted 10 July, 2000)
Code Number: CS00031
INTRODUCTION
The major obstacles to maize (Zea mays L.) production
in the West and Central African savanna are nitrogen deficiency and Striga
hermo-nthica parasitism (Berner and Kling, 1995). Striga is endemic
in West and Central African savannas and can cause serious devastation to maize
especially on the fields of resource-poor farmers (Parker, 1991; Lagoke et
al., 1994; Abayo et al., 1997). Even under good management condition,
about 79% reduction in yield was observed in susceptible hybrid maize . The
value of total annual crop loss due to Striga in Africa has been estimated
at 7 billion US Dollars.
Traditional African cropping systems which have included prolonged
fallow, rotation and inter-cropping were common management practices that were
used in the past to improve soil fertility and keep the infestation of Striga
spp at tolerable levels. However, increasing human population has resulted in
intensive land use and a shift away from traditional cropping systems, which
in turn has resulted in the depletion of soil fertility and decrease in Striga
control (Berner et al., 1996). Inter-cropping of maize with non
host crops has been reported to increase the efficiency of land use through
improved soil productivity and reduction of Striga hermonthica soil seed
bank as a result of the stimulation of suicidal germination of Striga
seeds by non hosts (Berner et al., 1996; Lagoke et al.,
1997; Oswald et al., 1997). Carson (1988), for example, found that Striga
densities were reduced when sorghum was intercropped with groundnuts. Similarly,
Odhiambo and Ranson (1993) and Carsky et al. (1994) tested maize/sorghum/cowpea
combinations and achieved a significant reduction of Striga population.
The spreading vegetation of non-host crops (trap-crops) also smother emerging
Striga plants. There is considerable variability among non-host crops
and within crop cultivars in their ability to fix nitrogen and stimulate Striga
seed germination. Varieties of soybean, cowpea, groundnut, pigeon pea and cotton
with very high Striga seed germination potential have been identified
(Carson, 1988; Ariga et al., 1994; Carsky et al., 1994).
These non-hosts, if identified for various production and cropping systems would
reduce soil seed bank and incidence of Striga hermonthica in maize.
MATERIALS AND METHODS
Field trials were conducted in 1997 and 1998 wet seasons at
Samaru (11°11N, 7°36E; 686 m above sea level) in the Northern Guinea savanna
agroecology of Nigeria. Treatments included a mixture of Striga tolerant
maize hybrid (Oba super 1) and two soybean varieties (TGX 1019-2E and TGX 1440-1E
- identified as potential trap-crop varieties) with a sole maize crop as control.
The treatments which were supposed to be evaluated on-farm were verified on-station
in a complete randomised block design replicated three times.
The trials were established on Striga sick plots which
were further inoculated with about 3,000 germinable Striga seeds hill-1
at about 50 cm apart. Maize seeds were planted on the spots one week later.
Intercropped soybean was drilled, on the same day, along the edges of the 75
cm spaced ridges. Spot application of fertiliser was carried out at the rate
of 100 kg N ha-1, 50 kg P2O5 ha-1 and 50 kg K2O ha-1 to maize using 20-10-10
compound fertiliser and urea. The intercropped soybean received a basal application
of 20 kg N ha-1 as starter dose using urea and 50 kg P2O5 using single super
phosphate (SSP - 18% P2O5). Hoe weeding was carried out at 3 and 5 weeks after
sowing (WAS) followed by hand pulling of other weeds which was carried out at
7 WAS. The plot size was 22.5 m2. Data collected included Striga incidence
(percentage of crop plants infested), infestation (Striga shoot count),
crop syndrome reaction score (where 1 = healthy plants to 9 = dead plants),
stand count, yield and yield components of maize and soybean. The data were
subjected to analysis of variance as described by Cochran and Cox (1957). Significant
differences among treatment means were compared using Fisher's protected least
significant difference (LSD) test at P=0.05.
RESULTS AND DISCUSSION
Striga incidence and infestation as reflected in the
Striga shoot count and number of maize plants infested by Striga
at 9 and 12 WAS were significantly (P=0.05) affected by the type of cropping
system (Table 1). Intercropping maize with soybeans supported lower incidence
and infestation of Striga and exhibited significantly (P=0.05) lower
crop syndrome reaction score than sole maize. Earlier reports indicated that
intercropping maize with non-host crops increase the efficiency of land use
through improved soil productivity and reduction of Striga hermonthica
soil seed bank (Ariga et al., 1997). In our study, emerged Striga
plants in the intercrop were etiolated in growth and died earlier than the Striga
that emerged in the sole crop probably as result of the smothering effect of
soybeans. This finding confirmed earlier report by Carson (1988) who found that
the spreading vegetation of non-host crops (trap-crops) also smother emerging
Striga plants.
The mixture of maize with soybean produced significantly (P=0.05)
higher grain yield than sole maize crop under Striga infestation (Table
2). Likewise, the mixture of local sorghum variety with soybean or cowpea produced
significantly (P = 0.05) higher head weight, 1000-seed weight and grain yield
than sole sorghum. Traditional African cropping systems which included rotation
and intercropping were common management practices in the past that improved
soil fertility, kept Striga infestation at tolerable levels and increased
seed yields of crops (Berner et al., 1996). Intercropping maize
with the two soybean varieties (TGX 1019-2EB and TGX 1440-1E) did not significantly
(P=0.05) affect Striga incidence, infestation, crop syndrome reaction
score and grain yield. This suggested that the soybean varieties tested had
similar potential for use as trap-crop varieties.
The soybean varieties tested differed only significantly (P=0.05)
in lodging and 100-seed weight (Table 3). TGX 1019-2EB was moderately susceptible
to lodging but produced significantly higher 100-seed weight than TGX 1440-1E.
Being an early maturing variety, TGX 1019-2EB was probably able to translocate
enough assimilate for seed filling before the end of the season. Thus, it produced
heavier seeds than TGX 1440-1E which is medium maturing.
As shown in Table 4, intercropping maize with soybean for Striga
suppression produced three times more crop value than sole maize crop. Kureh
et al. (1997, unpubl.) similarly reported that the highest crop value
was obtained when soybean was intercropped with either the farmers local sorghum
or improved sorghum variety than sole sorghum.
In conclusion, intercropping is a good agronomic practice for
Striga management in maize due to reduced striga infestation and
high total crop value obtained. Soybean varieties TGX 1019-2EB and TGX 1440-1E
exhibited similar potential for use as trap-crops.
REFERENCES
- Abayo, G.O., Oswald, A., Ransom, J.K. and Ariga, E.S. 1997. Stimulation
of Striga hermonthica germination by plant species indigenous to Eastern
Africa. In: In: Proceedings of the 16th Biennial Weed Science conference
for Eastern Africa, Kampala 15-18 September 1997. Adipala, E., Tusiime,
G. and Okori, P. (Eds.), pp. 231-239.
- Ariga, E.S., Berner, D.K. and Chweya, J. 1994. Effects of previous season
cotton and cowpea on Striga hermonthica parasitism on maize. Phytopathology
84: 1151.
- Ariga, E.S., Ransom, J.K. Odhiambo, G.D., Abayo, G.O. and Ndungu, D.K.
1997. Potential of using cotton and other trap crops for Striga hermonthica
management in cereals in Kenya. In: Proceedings of the 16th Biennial Weed
Science conference for Eastern Africa, Kampala 15-18 September 1997. Adipala,
E., Tusiime, G. and Okori, P. (Eds.), pp. 247-253.
- Berner, D.K., Alabi, M.O., Di-Umba, U. and Ikie, F.O. 1996. Proposed integrated
control program for Striga hermonthica in Africa. In: Proceedings
6th Parasitic Weeds Symposium, April 16-18th 1996, Cordoba, Spain. Moreno,
M.T., Cubero, J.I., Berner, D.K., Joel, D., Musselman, L.J. and Parket, C.
(Eds.), pp. 817-825.
- Berner, D.K., Kling, J.G. and Singh, B.B. 1995. Striga research and control:
a perspective from Africa. Plant Disease 79:652-660.
- Carson, A.G. 1988. Development and testing of a control package for Striga
hermonthica on small-scale holdings in the Gambia. Tropical Pest Management
34:97-101.
- Carsky, R.J., Singh, L. and Ndikawa, R. 1994. Suppression of Striga hermonthica
on sorghum using a cowpea intercrop. Experi-mental Agriculture 30:349-358.
- Cochran, W.G. and Cox, G.M. 1957. Experimental Designs. 2nd Edition. John
Wiley and Sons, New York. 611 pp.
- Lagoke, S.T.O., Shebayan, J.A.Y, Weber, G. , Olufajo, O.O., Elemo, K.A.,
Adu, J.K., Emechebe, A.M., Singh, B.B. and Adeoti, A.A. 1994. Survey of Striga
problem and evaluation of Striga control methods and packages in crops
in the Nigerian Savanna. In: Improving Striga Management in Africa.
Proceedings, 2nd General Workshop of PASCON, 23-29 June, 1991, Nairobi, Kenya.
Lagoke, S.T.O., Hoever, R., Mboob, S.S. and Traboushi, R. (Eds.), pp. 91-120.
FAO, Accra, Ghana.
- Odhiambo, G.D. and Ransom, J.K. 1994. Preliminary evaluation of long term
effects of trap cropping and maize management on Striga. In: Biology and
Management of Orabanche. Proceedings of the 3rd International Workshop
on Orabanche and related Striga research. Pieterese, A.H., Verklejj, J.A.
and ter Borg, S.J. (Eds.), pp. 505-512. Royal Tropical Institute, Amsterdam,
The Netherlands.
- Oswald, A., Ransom, J.K., Abayo, G., Kroschel, J. and Sauerborn, J. 1997.
Intercropping - an option for Striga control. In: Proceedings of the 16th
Biennial Weed Science conference for Eastern Africa, Kampala 15-18 September
1997. Adipala, E., Tusiime, G. and Okori, P. (Eds.), pp. 261-266.
- Parker, C. 1991. Protection of crops against parasitic weeds. Crop Protection
10:6-22.
TABLE 1. Effects of sole and intercropping of maize and soybean
on Striga incidence and infestation of maize at Samaru during the
1997 and 1998 wet seasons |
Cropping systems |
Stand count per plot at harvest |
Striga count per plot |
No. of infested plant per plot |
Crop reaction score3 |
9 WAS1 |
12 WAS |
9 WAS |
12 WAS |
9 WAS |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
Oba super 1 Sole |
54.1b2 |
55.3b |
31.0a |
27.3a |
35.0a |
30.6a |
21.7a |
19.0a |
24.0a |
21.0a |
4.5a |
4.3a |
Oba super 1 + TGX 1019-2EB |
60.3a |
61.5a |
13.0b |
10.3b |
15.3b |
12.2b |
6.3b |
4.7b |
6.7b |
5.0b |
3.0b |
2.3b |
Oba super 1 + TGX 1440-1E |
61.7a |
62.0a |
11.7b |
9.7b |
14.3b |
11.4b |
5.1b |
3.3b |
5.4b |
4.1b |
2.7b |
2.0b |
SE± |
1.19 |
1.20 |
2.51 |
2.32 |
5.01 |
4.21 |
2.67 |
2.41 |
2.92 |
2.62 |
0.30 |
0.24 |
1WAS = Weeks after sowing
2Means followed by the same letter or no letter within a column
are not significantly different at 5% level of probability (LSD)
3Crop syndrome reaction score using a scale of 1-9 where 1 =
healthy plants and 9 = dead plants |
TABLE 2. Effects of sole and intercropping of maize with soybean
varieties on yield and yield components of maize at Samaru during the 1997
and 1998 wet seasons |
Cropping systems |
No of cobs/plot |
Cob dry weight (kg ha-1) |
100-seed weight (g) |
Grain yield (kg ha-1) |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
Oba super 1 Sole |
50.3 |
56.7 |
1910.7 |
2807.3 |
19.3 |
19.9 |
1217.3b1 |
1408.7b |
Oba super 1 + TGX 1019-2EB |
64.3 |
65.0 |
2901.1 |
2659.0 |
19.7 |
21.2 |
2340.3a |
2568.7a |
Oba super 1 + TGX 1440-1E |
69.0 |
68.7 |
2986.5 |
2980.3 |
19.8 |
20.5 |
2970.0a |
3141.9a |
SE± |
6.63 |
7.21 |
315.52 |
187.31 |
0.30 |
0.47 |
264.35 |
275.53 |
1Means followed by the same letter or no letter within a column
are not significantly different at 5% level of probability (LSD) |
TABLE 3. Plant height, lodging, 100-seed weight and seed yield
of soybean varieties in a maize/soybean mixture at Samaru, 1997 and 1998
wet seasons |
Cropping systems 1997 |
Plant height (cm) |
Lodging score2 |
100-seed weight (g) |
Seed yield (kg ha-1) |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
|
Oba super 1 Sole |
- |
- |
- |
- |
- |
- |
- |
- |
Oba super 1 + TGX 1019-2EB |
81.0 |
81.9 |
3.7a1 |
4.0a |
24.4a |
15.2a |
1302.1 |
1437.0 |
Oba super 1 + TGX 1440-1E |
67.9 |
68.1 |
2.0b |
2.0b |
12.7b |
9.9b |
1113.2 |
1140.7 |
SE± |
3.20 |
3.15 |
1.46 |
1.52 |
0.73 |
1.09 |
109.99 |
153.35 |
1 Means followed by the same letter or no letter
within a column are not significantly different at 5% level of probability
(LSD)
2 Lodging score using a scale of 1-5 where 1 = all plants errect
and 5 = all plants lodged |
TABLE 4. Crop values of maize and soybean in sole and intercropping
of soybean with maize at Samaru, 1997 and 1998 wet seasons1 |
Cropping systems |
Maize grain yield (kg ha-1) |
Maize value at N20 kg-1 |
Soybean yield (kg ha-1) |
Soybean value at N25 kg-1 |
Total value (N) |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
1997 |
1998 |
Oba super 1 (Sole) |
1217 |
1409 |
24340 |
28180 |
- |
- |
- |
- |
24340 |
28180 |
Oba super 1 + TGX 1019-2EB |
2340 |
2569 |
46800 |
51380 |
1302 |
1437 |
32550 |
35925 |
79350 |
87305 |
Oba super 1 + TGX 1440-1E |
2970 |
3142 |
59400 |
62840 |
1113 |
1141 |
27825 |
28525 |
87225 |
91365 |
1Crop values were calculated using the prevailing
prices of test crops; 1 US$ = 90N |
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