Study the effect of plant population density and herbicide application on growth and development of Mahdavi wheat in Ney

1. 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

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-producedcerealaftermaize (784million tons) andrice (651million 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.

3. 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). 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).

4. 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 m2 (Neumann, 2005) 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.

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.

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)

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).

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

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.

10. Material and methods Experimental design was a Completely Randomized Design arrangement in split plot with four replications

11. Material and methods 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

12. Material and methods Treatments Plant density (Main factor) D1 = 250 plants per m2 D2 = 400 plants per m2 D3 = 550 plants per m2 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

13. Material and methods Different growth stages

14. Most important weed in wheat farms Acroptilon repens Avena fatua Solanum nigrum Alhagi camelorum Sinapis arvensis Convolvulus arvensis Setaria faberi Euphorbia aellenii Chenopodium album Centaurea sp Taraxacum officinale Sentaria verticillata

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)

16. Results and discussion Plant density had not significant effect on yield The highest seed yield was observed in 400 plant.m2 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. 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

17. There was positive correlation between plant density and number of spike per m2. The highest spike number was observed in 400 and 550 plant per m2 The highest and the lowest spike per m2 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

18. 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. 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

19. 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 m2. 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. 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

20. 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 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

21. The highest seed filling rate was observed in 400 plant per m2. Also the lowest was related to 550 plant per m2 There was benefit competition among plants in 400 plant per m2. 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). 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

22. The lowest spike number was observed in 250 plant per m2 The best treatment was 400 or 500 plant per m2 and T1 herbicide. Herbicide application decreased weed population and wheat tillering was increased Similar results are found by other researchers (Anderson, 2005; Grichar, 2006) 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

23. The highest number of spiklet in spike was related to 250 plant per m2 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. 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

24. 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. 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

25. 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). 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

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 m2,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 m2 and Tapik (1 liter per hectare) + Granestar (20 gr per hectare) application

27. Thank you very much for your attention Greece. Santorini Iran. Neyshabur Khayyam Tomb