EFFECT OF SELECTED INSECTICIDE ON WHITEFLY (Bemisia tabaci) INFESTING BRINJAL PLANTS 153 TRENDS AND VARIABILITY OF WHEAT CROP IN PAKISTAN Saleem Abida M. Asif Masooda M. Zubair Anwara Saleem Zahidb Irum Razaa aStatistics and Computing Program, Social Sciences Research Institute, PARC National Agricultural Research Centre, Islamabad, Pakistan. b Institute of Business and Management Sciences, The University of Agriculture, Peshawar, Pakistan.  saleemabidpk@gmail.com (Corresponding author) Corresponding Author ARTICLE HISTORY: Received: 18-Oct-2018 Accepted: 29-Dec-2018 Online Available: 17-Jan- 2019 Keywords: Trend, Growth, Variability, Semi-log model, Wheat crop ABSTRACT The main focus of the study was to analyze trends and variability of wheat crop in Pakistan. Semi-log trend model was used to find trends and growth rate in area, yield and production of wheat crop whereas the variability was measured by Cuddy-Della Valle index of variability. The findings of the study illustrate that wheat area in Punjab, Sindh and Baluchistan was increased over the time whereas cultivated area of wheat in Khyber Pakhtunkhwa province was marginally decreased during 1981-85 to 2011-15. The results show that there was substantial increase in wheat yield and production in all four provinces of Pakistan. The increase in wheat yield may due to the adoption of new varieties of wheat in the country over the time. It was also concluded from the results that area and yield of wheat in Baluchistan recorded the highest degree of variability whereas in Punjab province area and yield of wheat crop were noticed the lowest degree of variability. Similarly, the maximum variability in wheat production was recorded for Baluchistan province followed by Sindh, Khyber Pakhtunkhwa, and Punjab. Mostly the variability in wheat production was due to the variability in wheat area and their yield. Contribution/ Originality The present study was conducted to examine the growth and variability in area, production and yield of wheat crop in all provinces (i.e. Khyber Pakhtunkhwa, Baluchistan, Sindh and Punjab) of Pakistan. Information on growth performance and variability in wheat production would help the policy makers of the country to implement policy measures regarding the wheat crop. DOI: 10.18488/journal.1005/2018.8.2/1005.2.153.159 ISSN (P): 2304-1455/ISSN (E):2224-4433 How to cite: Saleem Abid, M. Asif Masood, M. Zubair Anwar, Saleem Zahid and Irum Raza (2018). Trends and variability of wheat crop in Pakistan. Asian Journal of Agriculture and Rural Development, 8(2), 153-159. © 2018 Asian Economic and Social Society. All rights reserved. Asian Journal of Agriculture and Rural Development Volume 8, Issue 2 (2018): 153-159 http://www.aessweb.com/journals/5005 mailto:saleemabidpk@gmail.com http://www.aessweb.com/journals/5005 http://crossmark.crossref.org/dialog/?doi=10.18488/journal.1005/2018.8.2/1005.2.153.159 Asian Journal of Agriculture and Rural Development, 8(2)2018: 153-159 154 1. INTRODUCTION Agriculture sector plays an important role in the economy of Pakistan which contributes 18.9 percent to GDP and absorbs 42.3 percent of labour force (Government of Pakistan, 2018). Wheat is grown extensively in Pakistan on a subsistence basis for home consumption. On average, the households incur 12.55 percent of the monthly expenditures on wheat and wheat flour (Government of Pakistan, 2017). The per capita wheat production in Pakistan is 131 kgs per year, while per capita wheat consumption is 118 kgs per year which is highest in the world (Govt. Khyber Pakhtunkhwa, 2014). Wheat productivity and yield are the important determinants of wheat supply. Availability of adequate food is of major concern at household, provincial and country level for food security. Any variation in the supply and demand of wheat in world market affects the welfare of farmers, consumers, taxpayers and those directly or indirectly dependent on agriculture (Jehangir et al., 2008; Hong-juan et al., 2017). Variability is an important measure of decision making in the dynamics of development and agricultural production. To analyze variations in crop production regardless of growth, it is important to understand the nature of income stability and food security. The variations in crop production affect prices and cause sharp fluctuations, but also lead to significant differences in income available to farmers. The magnitude of the variations depends on the nature of crop production technology, its sensitivity to weather, availability of inputs, economic environment, and several other factors (Wasim, 2011). Hazell (1989) found that due to the adoption of modern technology, global food grain production and the production of Indian food grains increased. Mehra (1981) argued that the variability in grain production has increased in India due to improved technological progress from the mid-1960s to large scale. Wasim (2001) evaluated that due to adoption of high yielding varieties and new farm technologies the variability in production increases. Similar opinions are also put forward by Ray (1983), Parthasarathy (1984), Mitra (1990) and Singh and Issac (2018). As wheat is a staple food of the country so it occupies a central place in Pakistan’s agricultural policies. The present study was conducted to examine the growth and variability in area, production and yield of wheat crop in all provinces (i.e. Khyber Pakhtunkhwa, Baluchistan, Sindh and Punjab) of Pakistan. Information on growth performance and variability in wheat production would help the policy makers of the country to implement policy measures regarding the wheat crop. 2. MATERIALS AND METHOD A time series data from 1980-81 to 2014-15 on area, yield and production of wheat for Baluchistan, Khyber Pakhtunkhwa (KP), Punjab and Sindh provinces was collected from different issues of Agricultural Statistics of Pakistan. 2.1. Linear semi-log trend function In order to find trends and estimate growth rate in area, yield and production of wheat crop semi- log trend function was used (Abid et al., 2014). lnZ = 0 + 1W+ e where Z = dependent variable (area, production and yield of wheat crop); 1 = trend coefficient; W = trend over specific period; ln = natural logarithm; and e = error term To find out the compound growth rate the following formula was used (Gujarati, 2004). r = {antilog(1) -1}*100 Asian Journal of Agriculture and Rural Development, 8(2)2018: 153-159 155 where r = Compound growth rate and 1 = trend coefficient. 2.2. Measurement of variability The variability in wheat area, yield and production was measured by Cuddy-Della Valle index of variability (1978) that is applied by different researchers in time series data. The formula for Cuddy-Della Valle Index of Variability (I) is I = CV∗ √(1 − 𝑅2 where CV represent the coefficient of variation; and R2 is coefficient of determination from a time- trend regression. 3. RESULTS AND DISCUSSION 3.1. Trends analysis of wheat crop Trends in wheat area, yield and production were presented in Table-1. The results from the table shows that the wheat area in Pakistan during 1981-85 was 7309 thousand hectares as compared to 8783 thousand hectares sown during 2011-15, which displays that wheat area increased by 22.2 percent over the time. The production of wheat was increased from 12053 thousand tonnes to 24688 thousand tonnes during 1981-85 to 2011-15, which indicate that wheat production in Pakistan was increased by 104.8 percent. It may be due to the corresponding increase in wheat area in Pakistan and also increase in wheat yield per hectare (67.8 percent) (Table 1 & Figure 1). Results of the study also illustrate that the wheat area in Punjab, Sindh, Khyber Pakhtunkhwa and Baluchistan was 5242,1021, 784 and 262 thousand hectares during 1981-85 whereas it was 6719, 1084,742 and 384 thousand hectares in 2011-15, respectively. So that the area under wheat crop in Punjab (28.2 percent), Sindh (6.2 percent) and Baluchistan (46.6 percent) was increased over the time. But the cultivated area of wheat crop in Khyber Pakhtunkhwa province was decreased by 5.4 percent during 1981-85 to 2011-15. Table 1: Trend of wheat crop in Pakistan, 1981-82 to 2014-15 (5-year averages) Year Punjab Sindh Khyber Pakhtunkhwa Balochistan Pakistan (Area in "000" Hectares) 1981-85 5242 1021 784 262 7309 1986-90 5577 1041 809 273 7700 1991-95 5855 1087 850 359 8152 1996-00 6029 1061 843 334 8268 2001-05 6263 888 738 334 8223 2006-10 6655 1048 751 387 8841 2011-15* 6719 1084 742 384 8929 (Production in "000" Tonnes) 1981-85 8653 2085 907 407 12053 1986-90 9817 2232 1023 527 13598 1991-95 11919 2313 1173 788 16193 1996-00 14258 2601 1095 707 18661 2001-05 15948 2328 1034 649 19960 2006-10 17768 3670 1149 775 23362 2011-15* 18837 3759 1253 840 24688 Yield in kgs per hectare 1981-85 1649 2042 1158 1551 1648 Asian Journal of Agriculture and Rural Development, 8(2)2018: 153-159 156 1986-90 1759 2144 1261 1945 1765 1991-95 2035 2128 1379 2202 1986 1996-00 2361 2466 1291 2114 2255 2001-05 2544 2618 1402 1948 2426 2006-10 2669 3497 1531 1994 2642 2011-15* 2803 3468 1688 2185 2765 Source: Government of Pakistan. 1990-2017 *4-year averages The average production of wheat crop in Punjab, Sindh, Khyber Pakhtunkhwa and Baluchistan provinces were 8653,2085,907 and 407 thousand tonnes during 1981-85 whereas it was 18837,3759,1253 and 840 thousand tons during 2011-15, respectively. The results shows that there was a substantial increase in production of wheat crop in all provinces of Pakistan. Similarly, it was exposed from the results that the yield of wheat crop was significantly increased in Punjab (70 percent), Sindh (69.8 percent), Khyber Pakhtunkhwa (45.8 percent) and Baluchistan (40.9 percent); it may be due to the introduction of new wheat varieties in the country over the time. Figure 1: Trend in area and production of wheat crop in Pakistan, 1981-82 to 2011-15 3.2. Growth analysis of wheat crop Estimated growth rates of wheat Crop during 1981-82 to 2014-15 were accessible in Table-2. It was revealed from the outputs that the semi log models were statistically significant for wheat area, yield and production in all provinces of Pakistan but wheat area model for Sindh province was statistically non-significant. The sign of trend co-efficient for yield and production of wheat was positive for all models of four provinces of Pakistan except wheat area for Khyber Pakhtunkhwa and Sindh provinces where the sign of trend co-efficient were negative. The positive sign of growth rate explain that wheat area, yield and production in Pakistan was increased at a rate of 0.65 percent, 1.90 percent and 2.56 percent per year, respectively. 7309 7700 8152 8268 8223 8841 8929 12053 13598 16193 18661 19960 23362 24688 0 5000 10000 15000 20000 25000 30000 35000 40000 1981-85 1986-90 1991-95 1996-00 2001-05 2006-10 2011-15 Area ('000' Hectares) Production ('000' Tonnes) Asian Journal of Agriculture and Rural Development, 8(2)2018: 153-159 157 Table 2: Estimated growth rate of wheat crop in Pakistan, 1981-82 to 2014-15 Wheat/Region Coefficient of Determination (R2) Trend Coefficient (b) t-Statistic Growth Rate (%) Area Pakistan 86.4 0.00651 14.26** 0.65 Khyber Pakhtunkhwa 23.8 -0.00316 -3.16** -0.32 Punjab 94.3 0.00858 22.92** 0.86 Sindh 0.10 -0.00033 -0.21NS -0.03 Baluchistan 52.0 0.0133 5.89** 1.34 Production Pakistan 95.2 0.0253 25.19** 2.56 Khyber Pakhtunkhwa 30.2 0.00755 3.72** 0.76 Punjab 94.0 0.0283 22.40** 2.87 Sindh 69.6 0.0196 8.56 ** 1.98 Baluchistan 50.2 0.0198 5.68** 2.00 Yield Pakistan 93.4 0.0188 21.24** 1.90 Khyber Pakhtunkhwa 59.6 0.0107 6.87** 1.08 Punjab 89.6 0.0197 16.6** 1.99 Sindh 83.4 0.0199 12.6** 2.01 Baluchistan 19.8 0.00654 2.81** 0.66 **Significant at 1% level of significance; NS=Non significant Table 2 illustrate that the compound growth rate for wheat area in Punjab and Baluchistan provinces were 0.86 percent and 1.34 percent, respectively. It means that the area under wheat crop in these two provinces were increasing at a rate of 0.86 percent and 1.34 percent per annum. In contrast, compound growth rate for wheat area of Khyber Pakhtunkhwa and Sindh were -0.32 and -0.03 percent, which indicate that area under wheat crop was decreased at the rate of 0.32 percent and 0.03 percent per annum in these two provinces, respectively. It was also exposed from the results that the compound growth rate of wheat production for Khyber Pakhtunkhwa, Punjab, Sindh and Baluchistan were 0.76, 2.87, 1.98 and 2.00 percent respectively, which explain that the production of wheat crop in the four provinces were increased at the rate of 0.76, 2.87, 1.98 and 2.00 percent per annum. The data also indicate that the yield of wheat crop in Pakistan as well as in all the four provinces were increased. 3.3. Variability in wheat crop The estimated relative variability index in wheat crop during 1981-82 to 2014-15 was presented in Table 3. It may be observed from the results that area and yield of wheat crop in Baluchistan recorded the highest degree of variability whereas in Punjab province area and yield of wheat crop were noticed the lowest degree of variability. Similarly, the maximum variability in wheat production was recorded for the Baluchistan province followed by Sindh, Khyber Pakhtunkhwa, and Punjab. Mostly the fluctuation in wheat production was due to the fluctuations in area under wheat crop and their yield. According to Goswami and Challa (2006), if variability in both area and yield components decline, then the variability in production is bound to decline. This is true with respect to wheat crop in Pakistan (Table-3). The results shows that the variability in wheat production had increased with the increased variability in area and yield, it may be due to the adoption of new technology. Asian Journal of Agriculture and Rural Development, 8(2)2018: 153-159 158 Table 3: Variability in wheat crop of Pakistan during 1981-82 to 2014-15 Provinces Instability Index For Area For Production For yield Punjab 2.1 6.0 5.8 Sindh 8.4 14.6 10.1 Khyber Pakhtunkhwa 5.8 11.0 8.2 Balochistan 11.7 18.8 12.7 Pakistan 2.5 5.2 4.5 Source: Author’s own calculation 4. CONCLUSION The results illustrate that the area under wheat in Punjab, Sindh and Baluchistan were increased over the time whereas cultivated area of wheat in Khyber Pakhtunkhwa province was marginally decreased during 1981-85 to 2011-15. The results show that there was significant increase in wheat yield and their production in the four provinces of Pakistan. The increase in yield of wheat was possibly due to the introduction of new varieties in the country over the time. The semi log models were statistically significant for wheat area, yield and production in all provinces of Pakistan except wheat area model for Sindh province which was statistically non-significant. It may be observed that area and yield of wheat in Baluchistan recorded highest degree of variability whereas in Punjab province area and yield of wheat were noticed lowest degree of variability. Similarly maximum variability in wheat production was recorded for the Baluchistan province followed by Sindh, Khyber Pakhtunkhwa, and Punjab. Mostly the variation in wheat production was due to the fluctuations in wheat area and their yield. The variability in wheat had increased, it may be due to the adoption of new varieties and better methods of cultivation, increase in variability of rainfall and prices and so on. Funding: This study received no specific financial support. Competing Interests: The authors declared that they have no conflict of interests. Contributors/Acknowledgement: All authors participated equally in designing and estimation of current research. Views and opinions expressed in this study are the views and opinions of the authors, Asian Journal of Agriculture and Rural Development shall not be responsible or answerable for any loss, damage or liability etc. caused in relation to/arising out of the use of the content. References Abid, S., Shah, N. A., Hassan, A., Farooq, A., & Masood, A. (2014). Growth and trend in area, production and yield of major crops of Khyber Pakhtunkhwa, Pakistan. Asian Journal of Agriculture and Rural Development, 4(2), 149-155. view at Google scholar Cuddy, J. D. A., & Della, V. P. A. (1978). Measuring of instability of time series data. Oxford Bulletin of Economics and Statistics, 40(1), 79-85. view at Google scholar Government of Pakistan. (2017). Household integrated economic survey 2015-16. Statistics Division, Pakistan Bureau of Statistics, Islamabad. Government of Pakistan. 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