Rainfall Distribution and Temperature Effects on Wheat Yield in Torbate Heydarie

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1 International Journal of Scientific Research in Knowledge, 2(Special Issue), pp , 214 Available online at ISSN: ; 214 Author(s) retain the copyright of this article Rainfall Distribution and Temperature Effects on Wheat Yield in Torbate Heydarie Raheleh Dehgahi*, Alireza Joniyas, Siti Noor Hajjar Binti MD Latip Faculty of Applied Science, University of Technology Mara, Malaysia *Corresponding Author, Abstract. Wheat is the most important crop in Iran, which is the main source of staple food and protein for the average Iranian. Wheat yields in Torbat Heydarie, Iran, are mainly limited by available water. A field experiment was conducted for winter wheat (Triticum aestivum L.) between to evaluate the effects of rainfall and temperature on wheat yield. The results showed that wheat yield depended on temperature, furthermore, grain yield was positively correlated with the average annual rainfall. The effect of rainfall and temperature on yield varied considerably between years. Keywords: wheat, Temperature, Rainfall distribution 1. INTRODUCTION Wheat (Triticum sp.) is a staple cereal crop worldwide. In 29, wheat was one of the three mostproduced cereals with maize and rice, which together, provide the vast majority of the global food requirement (Emami, 27). Wheat has been cultivated domestically since 9, B.C. in Turkey (Middle East). According to the World Bank, 27 ( agriculture in Iran contributes one fifth of the country's Gross Domestic Product, one third of employment, four -fifths of its food needs and one third of all non-oil exports. Wheat is used in whiskey and beer production. Before the introduction of corn into Europe, wheat was the principal source of starch (Zeng et al., 1997). World wheat production is greater than all other crops including rice, maize and potato (Briggle and Curtice, 1987). Based on the data published by the FAO, world wheat production increased 1.5% from 28 to 29 (Zand, 26). Wheat yield depends on a complex combination of genetic, environmental and management factors.yield is a result of the height of plants, the number of productive tillers, the number of grains per spike, the number of spikes per square meter and the thousand grain mass (Giunta et al., 23). In Khorasan province, irrigation is required 6-8 times over the entire planting/growth stage (55-8 m 3 /ha) (Khodabande, 1987). Temperature and rainfall are the most important factors for improving wheat production, especially during the grain filling period (Lopez et al., 23). The minimum temperature needed for germination varies depending on the variety. The average minimum temperature for germination is and maximum temperature is 2-22 (Emami, 27). High temperature decreases mean photosynthetic rates and mean total biomass (Monson et al., 1992). Wheat resistance to cold weather is relatively high - winter wheat planted in cold areas can tolerate -35. Wheat resistance to cold weather varies based on plant age and growth stage, so young plants are more sensitive (Emami, 27). Monson et al. (1992) reported that wheat photosynthetic rates are affected by high temperature. High temperature decreases mean photosynthetic rates and mean total biomass. The present study was aimed at determining the effects of rainfall distribution and temperature on wheat yield in Torbat Heidarie between METHODOLOGY 2.1. Plant material and experimental design The field experiments were conducted in Torbat Heydrie, Khorasan Razavi, Iran, during The site is at an altitude of 126 m, and has a semiarid climate. The soil is a dark loess soil with a loam texture, which has been intensively cultivated over many centuries. All plants were harvested in early July in the year following planting. 121

2 Wheat yield (kg/ha) Wheat area (ha) Fig. 1: Wheat area in Torbate Heydarie from 1993 to Fig. 2: Yield of wheat in Torbate Heydarie from 1993 to 28 Table 1: Variance analysis between rainfall and yield T Source DF Seq SS Adj SS Adj MS F P Rainfall Error Total S= R-Sq=99.77% R-Sq (adj)=98.27% 2.2. Secondary Data Collection In this study, the data collection method is by using secondary data. Secondary data of daily temperature and monthly rainfall took up from environmental Department (Khorasane Razavi) for each year to determine the climatic change effect in wheat yield. Data related to wheat area and yield from 1992 until 28 related to Torbate Heydarie were obtained from Head Quarter of Department of Agriculture, Khorasane Razavi. Wheat cultivation starts from October and continue until May. 122

3 3 25 Mean of rain fall (mm) Maximum of temperature ( C) Fig. 3: Distribution of mean of rainfall on Torbate Heydarie Fig. 4: Average of daily maximum temperature on the growth period 2.3. Statistical Analysis Data were classified and subjected to descriptive analysis. The data obtained were analysed by using Excel and Minitab (Anova) in order to determine the effect of rainfall and temperature on wheat yield in Torbate Heydarie. Descriptive statistics used graphical and numerical summaries to describe the main features of a collected in quantitative terms. 3. RESULTS AND DISCUSSIONS 3.1. Wheat area The wheat area distribution in Torbate Heydarie is presented in Fig. 1. Data collected for 16 years from 1993 to 28. The results of wheat area revealed that the largest cultivation area belongs to 1996 with the total of 36 hectares, while the lowest area recorded in 2 with the total of 355 hectares (Fig. 1). 123

4 Table 2: Variance analysis between maximum temperature and yield T Source DF Seq SS Adj SS Adj MS F P Max. Tem Error Total S= R-Sq=95.3% R-Sq(adj)=81.37% Table 3: Variance analysis between minimum temperature and yield S= R-Sq=61.7% R-Sq(adj)=.% Table 4: Variance analysis between mean of temperature and yield T Source DF Seq SS Adj SS Adj MS F P Mean. Tem Error Total S= R-Sq=59.61% R-Sq(adj)=.% 3.2. Wheat yield The wheat yield of Torbate Heydarie was taken from October 1992 to May 28. The highest yield of wheat was recorded in the years of 1993 and 1998 with the total of 41 kg/ ha while the lowest wheat yield recorded in 28 with the value of 956 kg/ha (Fig. 2). Fig. 1 and 2 present the results of wheat area and yield from 1993 to 28 respectively. Results indicated that there is no strong relationship between wheat area and yield Rainfall Various rainfall values over sixteen years from in Torbate Heydarie are demonstrated in Fig. 3. Rainfall values were recorded and being analysed from October to May for a period of sixteen years. For each year, the sum and mean of rainfall have been calculated over the cultivation period. Results reveal that reported maximum and minimum values of rainfall were in the range of 28.2 and 6.1 mm in 1992 and 28 respectively. The results of variance analysis between rainfall and yield in Torbate Heydarie over the period of revealed a strong relationship between rainfall and yield (P-value=. 15). It appears that the mean of rainfall values significantly affects wheat yield (Table 1). Our findings are in agreement with Giunta et al., 23 who stated that rainfall has a higher influence on wheat yields during cultivation because rainfall affect the available soil moisture during the reproduction period Temperature Maximum and minimum temperature were recorded daily and average of whole months in growing period being analysed from October until May, which counted for a period of sixteen years. For each year, a sum and mean of daily maximum and minimum temperature for eight months from planting month until harvesting month were being calculated. Data showed that maximum and minimum of temperature changed each year Mean maximum temperature Mean maximum temperature is the average of daily maximum temperature for each eight months of growing period. The highest maximum of temperature was 24.6 C in 22 while the lowest maximum temperature was in 1998 with the value of 21.2 C (Fig. 4). Table 2 revealed variance analysis between maximum temperature and wheat yield in Torbate Heydarie. Results indicated that average of maximum temperature and yield showed strong association. The maximum of temperature considerably affects wheat yield with the p-value of.38 (<.5). 124

5 Mean of Temperature ( C) Minimum of temperature ( C) Fig. 5: Average of daily minimum temperature on the growth period Fig. 6: Mean of temperature on the growth period 3.6. Mean minimum temperature Mean minimum temperature is the average of daily minimum temperature for each month during the growing period from planting to harvesting month (October to May). The highest mean of minimum temperature was -1.7 C recorded in 22 and the lowest recorded minimum temperature was -5.2 C in 28 (Fig. 5). Variance analysis results in Table 3 revealed a weak relationship between mean minimum temperature and yield. The minimum temperature did not significantly contribute in wheat yield with the p- value of.895 (Table 3) Mean of temperature Mean of temperature is the average of daily mean temperature within each month from planting to harvesting month. The highest mean temperature was in 22 with recording data of 11.4 C, while,

6 presented the minimum mean of temperature (9.1 C) (Fig. 6). The variance analysis in Table 4 indicated that there is a weak relationship between mean of temperature and yield. The mean of temperature does not significantly contribute to the yield of wheat with the p-value of.813 (>.5). The results showed that whereas there was no relationship between wheat yield and minimum and mean temperature, maximum of temperature significantly affect wheat yield over in Torbat Heydarie. Ayman (26) stated that high temperature during the growing season is able to decrease cereal yield by increasing evaporation rate. Furthermore, Wassenaarl et al. (25) indicated that seasonal precipitation and temperature significantly affect grain yields. 4. CONCLUSION In conclusion, reducing of rainfall in the growth period can affect wheat yield. The effects of rainfall on various years of cultivation differed, but generally there was a decrease in wheat yield with reducing of rainfall. Furthermore, higher maximum temperature over 15 years reduced wheat yield. The mean rainfall as much as mm and maximum temperature around C can present higher yield of wheat. Wheat varieties were sensitive to drought and temperature. To obtain higher yield in Torbate Heydarie, cultivation of resistant wheat varieties to drought and higher maximum temperature is strictly recommended by authors. REFERENCES Briggle L, Wand Curtice B C (1987). Wheat world and wheat improvement. American society of Agronomy. Southsegoe Road, Madison, Wisconsin, USA. PP: 34. Emami Y (27). Cereal production. Shiraz University Press. pp: Food and Agricultural Organization (25). FAOSTAT. Database for agriculture. Available online on: fao.org/faostat/ collection subset=agriculture. French RJ, Schultz JE (1984). Water use efficiency of wheat in a Mediterranean-type environment. I. The relation between yield, water use and climate. Australian Journal of Agricultural Research, 35(6): Giunta F, Motzo R, Deidda M (23). Effect of drought on yield and yield components of durum wheat and triticale in a Mediterranean environment. Field Crops Research, 33: Khodabande N (1987). Cereal culture. Sepehr edition. pp: Lopez CG, Banowetz GM, Peterson CJ, Kronstad WE (23). Dehydrin expression and drought tolerance in seven wheat cultivars. Crop Science, 43: Mendelsohn R, Nordhaus WD, Shaw D (1994). The Impact of Global Warming on Agriculture: A Ricardian Analysis.The American Economic Review, 84(4): Monson RK, Jaeger CH, Adams WW, Driggers EM, Silver GM, Fall R (1992). Fall Relationships among Isoprene Emission Rate, Photosynthesis, and Isoprene Synthase Activity as Influenced by Temperature. Plant Physiology, 98: World Bank Group, Zand A (26). The effect of herbicides on weed control and yield of wheat in irrigated uplands. Journal of Pesticides, 7: Zeng M, Craig F, Morris L, Batey L, Wrigley CW (1997). Sources of Variation for Starch Gelatinization, Pasting and Gelation Properties in Wheat. Cereal Chemistry, 74(1):