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Ethnobotanical
Leaflets 13: 450-58, 2009. Effect of Different Concentrations
of Imazaquin on Performance of Soybean (Glycine max). *K. S. Olorunmaiye, P. M. Olorunmaiye and O. A. Bukoye Department
of Plant Biology, *Correspondence
Author: e-mail:ksolorunmaiye@yahoo.com Issued Abstract An
experiment was conducted in order to examine the effect of different
concentrations of Imazaquin applied as both pre and
post emergence treatments on soybean plants. Soybean variety TGX 17402X was
used in this experiment. Results obtained revealed that efficacy of Imazaquin varies according to concentration and time of
application. Adequate weed control was achieved in all the concentrations of Imazaquin
with the best in concentration 0.375 kg a i./ha
applied as pre emergence and all the concentrations applied as post emergence
at 4 WAP (Weeks after planting) ,0.250 and 0.375 kg a i./ha
at 12 WAP. Stem height was best at higher concentration of 0.375 kg, a i./ha (45.00cm) at 8WAP while at
12 WAP, pre emergence concentration 0.250 kg. a i./ha and post emergence 0.375kg.ai./ha also produced
best stem heights of 67.00 and 68.00cm respectively. Leaf number was highest
in the control experiment with 50 leaves at 8 WAP followed by post emergence
concentration of 0.375 and 0.250 kg.a i./ha with 46.00 and 45.00
which were not statistically significant. However, the control, pre emergence
treatments of concentrations 0.125 and 0.375 kg. a i./ha, and the post emergence concentration of 0.375 kg. a i./ha were significantly
higher than the rest at 9 WAP (61,60,58 and 57 respectively). At 12WAP,
concentrations of 0.125 and 0.250kg. a i./ha at post and pre emergence application produced
significantly higher number of leaves than the remaining treatments. Weed
emergence was significantly higher in the control experiment at 4, 8, 9 and
12WAP. Key words: Glycine max, Imazaquin, Concentrations, pre
emergence, post emergence Introduction Soybean (Glycine max L. Merril) belongs to the family Fabacae. It is a very important staple food crop in The traditional method of hand weeding employed by farmers
in Materials and methods This experiment was carried out in an open space within
the premises of the Department of Plant Biology, The results were statistically analyzed
using analysis of variance (ANOVA) and the means were separated using Results and discussion Seed germination was observed in all the treatments at the
end of eight days after planting. Percentage seed emergence and seedling
establishment at 3WAP are shown in Table 1. Soybean stem heights at 8, 9 and
12WAP showed significant differences among the various herbicide
concentrations and time of application. Higher concentration of 0.375 kg a. i/ha applied as pre and post emergence produced the tallest
stem height of 45.00cm this was followed by the control experiment with
43.00cm at 8WAP, while concentration 0.250 kg a. i
/ha pre emergence and 0.375 kg a.i/ha as post
emergence produced tallest stem height of 48cm at 9WAP each. This was
followed by the control experiment 47.00 cm while concentration 0.375 kg a. i/ha post and 0.250 kg a.i/ha
pre emergence produced the tallest stem height of 68.00 and 67.00cm
respectively followed by the control experiment 65.00 cm at 12WAP ( Table 2).
Leaf number was highest in the control experiment 50.00cm
at 8WAP followed by 46.00 and 45.00cm at post emergence concentrations of
0.375 and 0.250 kg a i/ha
which were significantly lower than the pre emergence application treatment.
Control, pre emergence treatments of concentration of 0.375 kg a i/ha, with post emergence
concentration of 0.375 kg a i/ha were significantly
higher than the rest treatments at 9WAP (61, 60, 58 and 57) respectively
(Table 3). Leaf number at 12WAP at concentration 0.125 kg a.i/ha of post emergence
and the pre-emergence application of 0.125 kg ai/ha
were significantly higher than the rest treatments (Table 3). Weed emergence
was significantly higher in the control experiment at 4, 8, 9 and 12WAP
(Table 4). Post emergence application of the herbicide at 2 WAP killed the emerged weeds and rendered
the pots weed-free up to 4WAP (Table 4) however, there was a re-emergence at
8, 9 and 12WAP though significantly lower than the pre emergence treatments
at 9 and 12WAP (Table 4) Flowering was not affected by Imazaquin
except in the pre emergence application concentration of 0.125 kg a i/ha where only 33.3% of the
plants flowered at 6WAP. Other concentrations both at pre and post emergence
were at par with the control having 100% of the plants flowering at 6WAP
except at concentration 0.375 kg a i/ha pre and post emergence having 67% of its plants
flowering (Table 5). There were no pod formation at 9WAP in all the
treatments except in the post emergence treatment of 0.250kg a i/ha where 100% of the plants have
produced pods and the control 33.3% (Table 5). In general, pod formation was
significantly higher in post emergence treatment concentrations of 0.250 and
0.375 kg a.i/ha and pre emergence treatment
concentration of 0.375 kg a i/ha
have 100% of their plants producing pods at 10WAP, this was followed by the
control experiment 83% (Table 5). Generally, pod number and seed number per plant were
enhanced by both at pre and post emergence treatments of Imazaquin.
Pod weight was significantly reduced in the pre emergence concentration of
0.125 kg a i ha and post
emergence concentrations 0.250 and 0.375 kg a i
/ha. These were at par with the control treatment. Seed weight was
significantly reduced in the pre emergence herbicide treatment of 0.125 kg a i /ha (Table 6). The hazards arising from weed interference in crop
production system may result in both the reduction in yield and the quality
of the yield which invariably lead to loss of income to farmers (Mortimer,
1984, Norton and Conway, 1977). Imazaquin is an Imidazolinone herbicide widely used in weed control among
legume crops. High Soybean germination and seedling establishment in this
work is an indication that Imazaquin does not
inhibit germination processes as well as seedling development. This is in agreement
with the earlier findings of Adesina et al.1998, Olorunmaiye
and Onifade. (2001); Olorunmaiye
et al (2003), Fadayomi
and Olofintoye, (2005), and Olorunmaiye
(2008) Re-emergence of weeds in the treatments pointed to the
fact that re-application of herbicide may be necessary for adequate weed
suppression and a season long weed control. This agrees with the reports of Adesina et al.(1998) and Olorunmaiye,(2008)
who observed re-influx of weeds in plots 6 weeks after Imazaquin
application. Stem height was enhanced significantly at higher concentration
of 0.375 kg a i /ha both
at pre and post emergence application of Imazaquin.
Leaf number was equally enhanced by Imazaquin
concentrations both as pre and post emergence application at 12WAP. Generally pod and seed production were promoted by the use
of Imazaquin herbicide. Reproductive parameters
like pod number per plant, seed weight, Seed Number and seed weight per plant
and shoot dry weight were all significantly enhanced in all the treatments
(Table 6). Table 1. Effect
of Imazaquin concentration on percentage seedling emergence
and establishment at 3WAP*
Means
carrying the same letter along the same column are not significantly
different at P 0.05. *WAP=Weeks
after planting Table 2.
Effects of Imazaquin concentrations on soybean stem
height.
Means
carrying the same letter along the same column are not significantly
different at P 0.05 *WAP=Weeks
after planting Table 3.
Effects of Imazaquin concentrations on the leaf
number of soybean.
Means
carrying the same letter(s) along the same column are not significantly
different at P 0.05 *WAP=Weeks
after planting Table
4. Effects of Imazaquin
concentration on weed emergence.
Means
carrying the same letter(s) along the same column are not significantly
different at P 0.05 *WAP=Weeks
after planting Table 5.
Effects of Imazaquin concentration on time
flowering and pod formation.
Means
carrying the same letter(s) along the same column are not significantly
different at P 0.05 *WAP=Weeks
after planting Table 6.
Effects of Imazaquin concentrations on Soybean
yield components.
Means
carrying the same letter(s) along the same column are not significantly
different at P 0.05 References Adesina,
G. O., Akinyemiju, O. A. and Ayeni,
A. O. 1998. Control of weeds in
soybeans with Imidazolinone herbicides. Akobundu,
Akobundu,
Ayeni,
A. O. and Oyekan, P. O. 1992. Weed control in
soybean in Fadayomi,
O. and Olofintoye, J. A. 2005. Weed control in cowpea Vigna unguiculata L. Walp with imidazolinone
herbicide mixtures. Journal of Agric.
Research and Development 4 (2): 104-121. Kochhar,
S. L. 1981. Tropical Crops: A Text Book
of Economic Botany. Macmillan Publishers Mortimer, A.M. 1984.
Population ecology and weed science. Pp 363-388. In Perspectives on plant population ecology, R. Diizo
and J. Sarukhan (Eds.), Norton, G. A. and Conway, G.
R. 1977. The economic and social context of Olorunmaiye,
K. S. and Onifade O.O. 2001. Sensitivity of tomato ( Lycopersicon esculentus
) to residual effects of Imazaquin (Scepter). NISEB
Journal 1 (3): 267-272. Olorunmaiye,
K. S.; Olorunmaiye, P. M. and Onifade,
O. O. 2003. Effects of Imazaquin concentrations on
weed emergence and establishment. Journal
of the Nigerian Society for Experimental Biology 3(3): 87- 90. Olorunmaiye,
K. S. 2008. Responses of two cowpea (Vigna unguiculata (L) Walp) varieties to weed interference and control methods.
Ph.D,.Thesis. Department
of Plant Biology , Shaner,
D. L. and O’ Cornor, S. L. 1991. The Imidazolinone
herbicides, CRC Press, Yayock,
J. Y. 1999. Crop Science and production
in warm climate. Macmillan Publ. |
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