Study the effect of plant population density and herbicide
application on growth and development of Mahdavi wheat in Neyshabur
zone Presentation by: Prof. Seyed Ali Mohammad Modarres Sanavy
Agronomy Department, Faculty of Agriculture, Tarbiat Modares
University, Tehran, Iran Slide 2 Introduction Wheat ranks second
after maize in the world cereal output (FAO, 2005) and it is a
staple food for billions of people of the world (Satorre and
Slafer, 1999). In 2007 world production of wheat was 607 million
tons, making it the third most-produced cereal after maize (784
million tons) and rice (651 million tons). It is also the most
important winter cereal grown in Iran. In 2008 5,250,205 hectare
was under wheat cultivation and wheat production was 7,956,647.83
ton in this year. Slide 3 Optimum plant densities vary greatly
between areas according to climatic conditions, soil, sowing time,
and varieties. Most research on population density effects on crop
yield shows increases up to a plateau value at moderate densities
and a significant reduction in production only at very high
densities. Together with an optimal plant density, the uniform
distribution of the crop plants increases the vigor of the
individual plants and hence their grain yields (Weiner et
al.,2001). Plant density is one of the major factors determining
the ability of the crop to capture resources. It is of particular
importance in wheat production because it is under the farmer's
control in most cropping systems (Satorre, 1999). Slide 4 Wheat
production in Iran is limited by a number of factors, among which
is severe weed infestation (Montazeri et al., 2005). Weeds compete
with wheat for radiation, water and nutrients therefore reducing
crop yield (Grichar, 2006). Grain yield loss in wheat by weeds is
estimated to be 25% (Montazeri et al., 2005). Broadleaved weeds are
an increasing problem in many wheat growing areas in Iran that
consist 84% weed species infesting wheat fields. In the few studies
addressing the issue of seeding densities for small grain crops,
the seeding densities, irrespective of row spacing and seeding
technique, ranged widely between 100 and 500 seeds m 2 (Neumann,
2005) Slide 5 Current weed control strategies include crop
rotations, mechanical practices, cultivation, hand weeding and
herbicide use (Soufizadeh et al., 2007). However, many researchers
have reported that mechanical practices like hoe weeding do not
satisfactorily control weeds in wheat (Dadari and Mani, 2005). This
has probably been attributed to the fact that due to the dense
wheat population, only some inter-row weeds were eliminated during
hoe weeding, thus leaving some intra-row weeds to escape control.
Slide 6 Zand et al. (2006b) also found that hand weeding might not
always be considered as the best weed control method in wheat
because of possible damages of hand weeding on wheat crops.
Regarding these findings and due to economic factors, herbicides
are the major weed control method in most cropping systems in Iran
including winter cereal monoculture (Zand et al., 2006b). In Iran,
herbicides have been the main means of weed control for more than
30 years (Zand et al., 2006b) Slide 7 Currently, different
herbicides are used in wheat in Iran such as diclofop methyl,
fenoxaprop-p-ethyl, and clodinafop propargyl as grass weed
herbicides and tribenuron methyl, bromoxynil plus MCPA, and 2,4-D
plus MCPA as broadleaved weed herbicides (Zand et al., 2002). Slide
8 Objective of study 1- Effect of plant population density on yield
and yield component of the wheat 2- Comparison of five herbicides
and selection of the best herbicide Slide 9 Material and methods
The experiment was conducted in 2007 growing season in Neyshabur
zone Neyshabur is in North East of Iran in Khorasan province.
Nyshabur having very cold winters, pleasant springs, usually mild
summers, and beautiful autumns. Latitude36.47Longitude58.48Altitude
(m)1350 Slide 10 Experimental design was a Completely Randomized
Design arrangement in split plot with four replications Material
and methods Slide 11 Seed bed preparation was included: Plow, disk
and leveler The seeds (Mahdavi cultivar) were sown in three plant
density The experimental plots were irrigated at field capacity
level The herbicides application was done when plants were at five
leaf stages Material and methods Slide 12 Plant density (Main
factor) D1 = 250 plants per m 2 D2 = 400 plants per m 2 D3 = 550
plants per m 2 Herbicides (Sub factor) T1 = Tapik (1 liter per
hectare) + Granestar (20 gr per hectare) T2 = Assert-IPU (4 liter
per hectare) T3 = Tapik (1 liter per hectare) + Sinal (125 cc per
hectare) T4 = Panter (2 liter per hectare) T5 = Control Treatments
Slide 13 Different growth stages Material and methods Slide 14 Most
important weed in wheat farms Acroptilon repens Convolvulus
arvensis Chenopodium album Centaurea sp Avena fatua Alhagi
camelorum Euphorbia aellenii Taraxacum officinale Solanum nigrum
Sinapis arvensis Setaria faberi Sentaria verticillata Slide 15
Material and methods Herbicides characterization and application
Granestar (sulpho demeton methyl) is post-emergence and selective
herbicide. Tapik (Clodinafop propargyl ) is post emergence and
selective herbicide. Topik is from oxyphenoxy acid ester group and
content of 80 gr/l clodinafop- propargyl. Sinal (Metosulam) is post
emergence herbicide. Sinal is from triazolopyrimidine group and has
100 ppm active substance of Metosulam. Assert IPU is post
emergence-selective herbicide. Assert and IPU are from imidazolone
and phenyl-urea groups respectively. Panter (Diflufenican) pre and
post emergence. Panther is mixture of isoproturon and diflufenican
(diflufenican 50 + isoproturon 500 g a.i./l) Slide 16 Results and
discussion T1 = Tapic (1 liter per hectare) + Granestar (20 gr per
hectare) T2 = Asert-IPU (4 liter per hectare) T3 = Tapic (1 liter
per hectare) + Sinal (125 cc per hectare) T4 = Panter (2 liter per
hectare) T5 = Control Plant density had not significant effect on
yield The highest seed yield was observed in 400 plant.m 2
treatment The highest seed yield was achieved from T1 treatment
that is Tapik (1 liter per hectare) + Granestar (20 gr per
hectare). The lowest seed yield was achieved from T5 treatment that
is control (without any weed control). Results of Stougaard et al.
1997 are agree with our results on seed yield. Also improve of
grain yield has been reported by Walker et al. 2002. Slide 17 There
was positive correlation between plant density and number of spike
per m 2. The highest spike number was observed in 400 and 550 plant
per m 2 The highest and the lowest spike per m 2 were in T1 and T2
and T5 treatments, respectively. Bostromand Fogelfors 2002 have
been showed that mixture of herbicides are more effective to weed
control. Also Ahmad et al. (1991) found that mixture of Dicuron MA
60 + DMA-6 was more economical than other herbicidal treatments
giving better weed control and grain yield. T1 = Tapic (1 liter per
hectare) + Granestar (20 gr per hectare) T2 = Asert-IPU (4 liter
per hectare) T3 = Tapic (1 liter per hectare) + Sinal (125 cc per
hectare) T4 = Panter (2 liter per hectare) T5 = Control Slide 18 T1
= Tapic (1 liter per hectare) + Granestar (20 gr per hectare) T2 =
Asert-IPU (4 liter per hectare) T3 = Tapic (1 liter per hectare) +
Sinal (125 cc per hectare) T4 = Panter (2 liter per hectare) T5 =
Control Plant density had significant effect on number of spiklet
in spike. Increase of plant population decreased number of spiklet.
Weed control increased number of spiklet in spike, in T1 and T2
treatments there were the highest spiklet in spike. The best
herbicides were Tapik + Granestar and Assert-IPU Soltani et al.
(2006) came to the similar finding with bromoxynil plus MCPA. Slide
19 T1 = Tapic (1 liter per hectare) + Granestar (20 gr per hectare)
T2 = Asert-IPU (4 liter per hectare) T3 = Tapic (1 liter per
hectare) + Sinal (125 cc per hectare) T4 = Panter (2 liter per
hectare) T5 = Control There was negative correlation between the
highest plant density and seed number per spiklet. The highest seed
number was observed in 250 and 400 plant per m 2. T1 and T2
treatments had the highest seed number per spiklet. In general weed
control by herbicides increased seed number. Akhtar et al. (1991)
found that application of grassy and broad leaf herbicides
increased grain yield and yield components. Slide 20 T1 = Tapic (1
liter per hectare) + Granestar (20 gr per hectare) T2 = Asert-IPU
(4 liter per hectare) T3 = Tapic (1 liter per hectare) + Sinal (125
cc per hectare) T4 = Panter (2 liter per hectare) T5 = Control Seed
weight was not affected by plant density, it seems that seed weight
is related to genotype. The plant density is more effective on
number of tillers in plants and finally on number of seeds. Number
of seeds are more affected by plant population than seed weight
Also there was not any significant difference among herbicides on
1000 seed weight Slide 21 T1 = Tapic (1 liter per hectare) +
Granestar (20 gr per hectare) T2 = Asert-IPU (4 liter per hectare)
T3 = Tapic (1 liter per hectare) + Sinal (125 cc per hectare) T4 =
Panter (2 liter per hectare) T5 = Control The highest seed filling
rate was observed in 400 plant per m 2. Also the lowest was related
to 550 plant per m 2 There was benefit competition among plants in
400 plant per m 2. But at the highest plant density excess
competition lead to decrease of seed filling rate due to deficiency
of growth resources. Herbicide application increased seed filling
rate and the best herbicides was Tapik + Granestar. Herbicides
decreases enter competition and seed filling will be increased
(Tomlin, 2003). Slide 22 The lowest spike number was observed in
250 plant per m 2 The best treatment was 400 or 500 plant per m 2
and T1 herbicide. Herbicide application decreased weed population
and wheat tillering was increased T1 = Tapic (1 liter per hectare)
+ Granestar (20 gr per hectare) T2 = Asert-IPU (4 liter per
hectare) T3 = Tapic (1 liter per hectare) + Sinal (125 cc per
hectare) T4 = Panter (2 liter per hectare) T5 = Control Similar
results are found by other researchers (Anderson, 2005; Grichar,
2006) Slide 23 T1 = Tapic (1 liter per hectare) + Granestar (20 gr
per hectare) T2 = Asert-IPU (4 liter per hectare) T3 = Tapic (1
liter per hectare) + Sinal (125 cc per hectare) T4 = Panter (2
liter per hectare) T5 = Control The highest number of spiklet in
spike was related to 250 plant per m 2 and Topik and Granestar
application. The lowest number of spiklet in spike was achieved
from without herbicides treatment. Increase of spiklets in spike
due to herbicide application is related to decrease of competition
and improve of vegetative stages and increase of photosynthesis.
William (2004) Reported that, decrease of competition causes a
increase in growth and enhancement of generative cells. Slide 24 T1
= Tapic (1 liter per hectare) + Granestar (20 gr per hectare) T2 =
Asert-IPU (4 liter per hectare) T3 = Tapic (1 liter per hectare) +
Sinal (125 cc per hectare) T4 = Panter (2 liter per hectare) T5 =
Control There was not significant difference among plant densities,
but herbicides application increased number of seeds in spikes. It
seems that, herbicide application decreased competition and
increased number of reproductive cells and spiklets. Shahida et
al., 2008, have been reported that, herbicides application
increased seed number in wheat. Slide 25 T1 = Tapic (1 liter per
hectare) + Granestar (20 gr per hectare) T2 = Asert-IPU (4 liter
per hectare) T3 = Tapic (1 liter per hectare) + Sinal (125 cc per
hectare) T4 = Panter (2 liter per hectare) T5 = Control It observed
that, herbicide application in three plant densities increased seed
filling rate. Decrease of competition between crop and weed, and
increase of water, light and mineral nutrition availability leads
to improve of seed filling rate The Tapik + Granestar treatment was
known as the best treatment in different plant population
densities. Improve of seed filling rate due to herbicide
application have been reported by many researchers (Defelice, 2002;
Roberts et al., 2001). Slide 26 In conclusion Different levels of
plant density and interaction effect of between density and
herbicide had not significant effect on seed yield Effect of
herbicide application was significant at 5% probability and the
best herbicide treatment was Tapik (1 liter per hectare) +
Granestar (20 gr per hectare) Interaction effects were significant
on number of spike per m 2,number of spiklet in spike, number of
seed in spike and linear seed filling rate According to our results
the best treatment was 400 plant per m 2 and Tapik (1 liter per
hectare) + Granestar (20 gr per hectare) application Slide 27 Thank
you very much for your attention Greece. SantoriniIran. Neyshabur
Khayyam Tomb
