PRODUCTIVITY IMPACT OF THE MODERN VARIETIES OF RICE IN INDIA

Transcription

1 The Developing Economies, XLIV-2 (June 2006): PRODUCTIVITY IMPACT OF THE MODERN VARIETIES OF RICE IN INDIA Blackwell Oxford, DEVE The June 44 2Original modern the developing Developing 2006 The rice UK Article Author(s) Publishing varieties economies Economies & Ltd in Institute india of Developing Economies Aldas JANAIAH, 1 Mahabub HOSSAIN, 2 and Keijiro OTSUKA 3 1 National Centre for Agricultural Economics and Policy Research, New Delhi, India; 2 Social Sciences Division, International Rice Research Institute, Metro Manila, Philippines; and 3 Foundation for Advanced Studies on International Development and National Graduate Institute for Policy Studies, Tokyo, Japan First version received June 2005; final version accepted February 2006 The present paper analyzed the long-term yield growth and total factor productivity (TFP) growth by applying Tornqvist-Theil index method for two periods, namely, (early Green Revolution) and (late Green Revolution), for major rice-growing states of India. The yield data shows an increasing long-term growth trend throughout the Green Revolution period in irrigated states where modern variety (MV) adoption was nearly complete. However, yield advances started to slow down for intensive irrigated rice systems in the 1990s, whereas rainfed ecosystems have increased during the late Green Revolution period. The domestic spillovers of MV from irrigated to rainfed states is likely to be one of the contributing factors to increased TFP growth in ranifed areas after the 1980s. This implies that the MV of rice developed for irrigated ecosystems have also benefited substantially the rainfed-dominant eastern Indian states in the long run where partial irrigation facilities such as shallow tube wells were created after the mid-1980s. Keywords: Green Revolution; Total factor productivity growth; Modern varieties of rice; Ecosystem; India JEL classification: O3 I. INTRODUCTION A lthough cropped area under food grains (cereals, millets, and pulses) declined by 2%, total food grain production rose from 103 to 206 million tons in India between the triennium ending 1970 and 2000, which can be termed the Green Revolution (GR) period. The phenomenal increases in yield of rice and wheat crops were the chief sources of increased food grain production over the past three decades. However, the growth rate of rice yield slowed down in the late GR Authors express sincere thanks to the anonymous referee who provided extremely useful suggestions and comments on a previous version of the paper. The Developing Economies, XLIV-2 (June 2006): XXX XXX doi: /j x

2 modern rice varieties in india 191 period ( ) compared with the early GR period ( ). Many recent studies report that rice yields were either declining or stagnant after the 1980s under the intensive irrigated rice ecosystems (Flinn and De Datta 1984; Cassman and Pingali 1995; Nambiar 1988; Pingali, Hossain, and Gerpacio 1997; Greenlands 1997; Yadav, Dwivedi, and Pandey 2000; Dawe et al. 2000; Kumar and Yadav 2001). Most of these studies were based on experimental data designed with specific objectives under controlled environments (e.g., fixed nutrient doses, variety, and other management practices) in the research farms and adaptive research trials. These studies provide an impression that productivity impact of technological progress has been vanishing in the irrigated ecosystems. The yield trends of modern varieties (MV) from the controlled environment, however, might not be matched with those of the farmers fields (real farm environment), because farmers adopt new improved MV and adjust their farm practices over the long period to cope with the changing production and micro-policy environments. Furthermore, yield growth is not a true measure of technology impact, as it does not net out the effect of input growth from output growth. Thus, total factor productivity (TFP) growth is a correct measure of the efficiency at the farm level (Evenson and Prey 1991). The crop breeders have released nearly 620 types of MV of rice over the past 35 years in India. The MV released till the mid-1970s were largely higher-yielding under ideal production environments, whereas subsequent generations of MV were characterized by improved resistance to pests and diseases and improved grain quality (DRR 2001). These improvements in the successive generations of MV are expected to contribute to TFP growth in three ways, namely, lowering the cost of production, higher market price per unit of output, and lowering downward yield instability. The principal goal of the paper is to test empirically three key hypotheses regarding the productivity impacts of successive generations of MV. First, in view of improvements in various traits of MV over the period, the productivity growth as measured by TFP is expected to increase throughout the GR period. Secondly, instability in crop yield is expected to decline as adoption of new MV with better traits increases over the period. Finally, despite the fact that yield gains of MV have almost saturated in the irrigated ecosystems for which these MV were originally developed, the rainfed ecosystem, where new irrigation facilities such as shallow and tube wells were created, is expected to receive external benefits from these MV transferred from the irrigated ecosystems through domestic spillovers. The paper is organized as follows. The data sources and methods of analysis are explained in the next section. Section III examines the development and adoption of MV of rice and their spillovers across states. Section IV discusses the long-term growth trends of yield, TFP, and instability of rice yield across the Indian states. The last section concludes with summary and policy implications.

3 192 the developing economies II. DATA SOURCES AND METHODS OF ANALYSIS Two sets of data were used for the study. First, the state-level time-series data on quantity of output and input use levels, and prices of output and inputs, compiled from the reports of Cost of Cultivation of Principal Crops published by the Ministry of Agriculture, Government of India (GOI-MOA, various years) for the period were used to estimate TFP growth for the selected major states of India. Thus, there were 29 observations (number of years) in each state for measurement and analysis of TFP growth. Under Cost of Cultivation Scheme, farm-level input-output data for all major crops were collected from a large number of sample farmers (vary from state to state) representing all ecosystems in all major states every year since , and periodical reports of the scheme were published with the state-level average figures of all inputs, outputs, and their values. In addition, state-level statistics on area, production and yields, area irrigated, and area planted with MV were compiled for the period 1970 to 2001 from the respective state s Bureau of Economics and Statistics. Second, the relevant data on basic characteristics and origin (where MV was developed and/or released) of all released MV of rice in different states of India for the period were compiled from the research reports and bulletins of Indian Council of Agricultural Research (ICAR 1992), Central Rice Research Institute (CRRI 1996), and Directorate of Rice Research (DRR 2001). The area under specific crop varieties is not available from any published official documents until now, even though such data is recorded for major crops such as rice and wheat in unorganized and unpublished documents within state agriculture departments. The data on area and yield for all MV of rice grown by the farmers during and in 14 major rice producing states accounting for approximately 97% of India s rice area and production were compiled from these unpublished records with the concerned state s Department of Agriculture (SDA). The SDA in each state maintains the variety-wise area and yield for major crops, which is compiled from various districts of the state every year. District-level agriculture department officials including a statistician compiles MV-wise area based on seed sales both by public sector and private sector seed agencies of various MV. Yield figures for various MV estimates from crop-cutting experiments, which are done in a large number of representative sample farms in every district every year under the supervision of district-level statistician throughout the country for estimation of crop yields. This data was analyzed to assess the contribution of MV released over the past 30 years. Further, we also assessed domestic spillovers through interstate/regional movement of MV from one state to other and their impacts across Indian states. A. Estimation of TFP Growth The TFP growth measures growth in output contributed by factors other than input growth. Thus, drawing on Solow (1956), TFP is considered as a conventional

4 modern rice varieties in india 193 indicator of technological progress over time. There are a number of studies in recent years on measurement and analysis of TFP for various crops and/or group of crops in Indian agriculture (Kumar and Mrithyunjaya 1992; Sidhu and Byerlee 1992; Rosegrant and Evenson 1992, 1993; Dholakia and Dholakia 1993; Kumar and Rosegrant 1994; Fan, Hazell, and Thorat 1998; Evenson, Pray, and Rosegrant 1999; Pingali and Heisy 1999). Most of these studies used either Divisia index or alternatively Tornqvist-Theil index of TFP. These studies report that TFP growth for various crop sectors and agricultural sector in India was approximately 0.6% to 1.3% per year during , with a deceleration in TFP growth after the mid-1980s. For this paper, Tornqvist-Theil index method is applied for TFP estimation because of not only its methodological superiority over conventional Divisia index (Rosegrant and Evension 1992), but also its simplicity in estimation, especially for a single crop. The TFP index formula is specified as below. TFPt QIt XIt TFP TFP = QI ln ln ln XI = where QI t is the total output index, XI t is the total input index, and S jt are factor shares of input j at time t. As explained above, the state-level time-series data on quantity of output and input use levels, and prices of output and inputs, compiled from the reports of Cost of Cultivation of Principal Crops for the period (GOI-MOA, various years) were used to estimate TFP growth for the selected major states of India. Thus, there were 29 observations (number of years) in each state for estimation of TFP growth. All major inputs such as seeds, fertilizers, manures, human and animal labor, machinery, and irrigation were included in the estimation of TFP. As only value figures were available for machinery and irrigation inputs in the cost of cultivation reports (GOI-MOA, various years), diesel price per liter for year t was used to calculate the quantity of diesel (liters per hectare) for year t, which was included in the computation of input index as a proxy for machinery. Similarly, electricity charges per horse power (HP) for year t were used to compute total quantity of electricity (number of HP per hectare) from the irrigation charges, and same has been used for estimation of input index for year t. B. Estimation of Instability The instability indices for farm-level yields of rice were estimated separately for early and late GR periods in the selected states. The following formula is used to compute instability indices: I = [SD Σ ln(y t /Y t 1 )] * 100, t 1 t 1 t 1 QIt 1 + XI ln S S ln QI jt jt 1 t 1 2 XIjt jt ( ), j 1

5 194 the developing economies where I refers to instability index (%) that measures the magnitude of year-to-year fluctuations in incremental yield changes over the period; SD stands for standard deviation; Y t is crop yield during tth year and Y t 1 is yield during (t 1)th year. III. DEVELOPMENT AND ADOPTION OF MODERN VARIETIES Two sets of data were used to examine development and release of MV, and their adoption rates across Indian states. First, the variety-wise characteristics of all MV released in different states of India during , and source of origin where each MV was developed were compiled from the research reports and bulletins of ICAR (1992), CRRI (1996), and DRR (2001). Second, data on area and yield for all MV of rice grown by the farmers during and in 14 major rice-producing states that were compiled from the unpublished records with the concerned SDA. The improvement of MV of crops entails a dynamic process to develop successive generations of MV with new traits demanded by farmers and consumers. Although higher yield potential of MV was a principal source of productivity growth during the early GR period, the improved traits, such as better grain quality and resistance to pests and diseases in the successive generations of MV, are expected to contribute to productivity growth at a later stage of the GR period. Furthermore, the MV that were developed for and adopted widely in the irrigated ecosystems are expected to spread into rainfed areas where new irrigation sources such as shallow and tube wells were created over the long period by spillover effects. This section describes development and adoption of MV by traits, as well as inter-regional spillovers of MV over the period. 1 A. Development and Release of Modern Varieties India s rice-breeding program in public sector has been developed with wellinstitutionalized coordinated network since the inception of All India Coordinated Rice Improvement Project (AICRIP) in 1965, covering approximately 100 research institutions across the state. The AICRIP provides a free movement of a MV from one state to other irrespective of source of origin of MV. 2 1 Lack of time-series data on MV-wise adoption rates constrained any rigorous analysis to explain effects of various variety traits on adoption rate of a particular MV, and their ultimate effects on TFP over the period under examination. Since MV-wise adoption rate is available for only two crop years ( and ), a simple and straightforward descriptive analysis was done to examine adoption pattern of various MV by variety-traits and year of release. This analysis provides factual information on adoption pattern of all MV grown during crop years across states. 2 AICRIP facilitates research partnership between different R&D institutions within the India. Four major activities are done under the AICRIP-network, namely, varietal development (plant breeding), plant protection, natural resources management, and transfer of technologies through nationwide

6 modern rice varieties in india 195 TABLE 1 Number of Modern Varieties (MV) of Rice Released for Major Production Environments in India, Period No. of MV Released Share for Different Ecosystem (%) Irrigated Rainfed Upland Rainfed Lowland Source: Complied from various reports of ICAR (1992), CRRI (1996), and DRR (2001). The number of MV of rice released from different states of India was 620 during the period Among the released MV, 54% were recommended for the favorable irrigated ecosystem, 27% for the rainfed lowland, and 19% were for the rainfed upland ecosystem (Table 1). The proportion of MV released for the rainfed ecosystems increased steadily over the 35-year period. The number of MV released has increased substantially since the mid-1980s. Indeed, two-thirds of total number of MV were released during (late GR period). on-farm/frontline demonstrations of new MV. Among them, varietal development activity is the lifeline for overall R&D through AICRIP. The identified elite lines of improved cultivars (after initial breeding process for 6 7 years) are pooled at AICRIP headquarter (Directorate of Rice Research a cording center of AICRIP, Hyderabad) from all participating RD institutions and tested in as many locations as possible all over the country for three to four crop seasons at research station sites, and one season in the farmers field (evaluation trials) through the coordinated network mechanism. A Central Variety Release Committee (CVRC) under the Ministry of Agriculture examines the performance of the tested cultivars based on the coordinated trials and approves it for the release as a MV for India as a whole if it is found suitable for more than one state. If a cultivar is found suitable only in one state, the concerned state agricultural university would approve the release of that cultivar as the MV for the state. An elite/improved cultivar that is developed in a state/institution might also be released by other states, if it was found suitable through coordinated variety-testing mechanism. This is the most powerful means that facilitate many MV move from one state/ institution to other through institutionalized network, which has an inbuilt transparent mechanism for free sharing of improved germplasm in all concerned scientists/institutions. Another means through which MV moves from one state to other is on-farm/frontline demonstrations program, being conducted by AICRIP network. All potential MV (mostly released MV) are identified from different states and seeds of these MV are distributed to all targeted states, irrespective of where these MV are released/developed, for frontline demonstrations in farmers fields in consultation with the concerned state s department of agriculture. The participating states are allowed to promote any MV, if it is found suitable and outperforming in the farmers fields through frontline demonstrations.

7 196 the developing economies TABLE 2 Share of Adopted Modern Varieties (MV) in Total Released MV and Their Adoption Rate by Period of Release of MV in India, Period of Release Total Released MV Released MV Adopted during (%) Adoption Rate (%) Yield (ton/ha) Total Source: Complied from various reports of ICAR (1992), CRRI (1996), DRR (2001), and from state Departments of Agriculture. TABLE 3 Area Planted to Modern Varieties (MV) of Rice by Resistance to Pest and Diseases in India, Reaction of MV Number of Adopted MV Million ha Area Planted % of Total No resistance Resistance to single pest/disease Multiple resistance All MV Source: Compiled from state Departments of Agriculture. Over the last several decades, R&D strategy has been changing its priorities to meet the growing needs of rice farmers and consumers. Most of the MV released were of slender grain type (considered as better grain quality) throughout the period, indicating a positive response of rice-breeding program to meet the increasing demand for better quality rice. B. Adoption Rate of Released Modern Varieties Actually farmers adopted only 221 out of the 620 MV of rice released in India during For example, although approximately 50% of MV released in the 1990s (new MV) were adopted during in different states, their total adoption rate was only 28% (Table 2). Among all adopted MV, the top 30 MV that were adopted in more than one state covered 61% of total MV area. Approximately

8 modern rice varieties in india 197 TABLE 4 Area Planted to Modern Varieties (MV) of Rice by Type of Grain in India, Grain Type Number of Adopted MV Million ha Area Planted % of Total Long slender Medium slender Long bold Medium bold Short bold All MV Source: Compiled from state Departments of Agriculture. three-fourths of the total area planted with the top 30 MV was covered by those MV that were developed and released before 1990, which can be called early MV. Nearly 38% of India s rice area was planted to those MV that were released during (early MV). Recent case studies based on sample surveys in the irrigated ecosystems also report that approximately 75 90% of rice area on sample farms was planted to those MV that were released before 1990 (Singh, Janaiah, and Hossain 2000; Gowda, Janaiah, and Hossain 2000; Janaiah, Singh and Hossain 2000). This implies that the MV developed in the early 1980s are still more popular with Indian farmers. As a matter of fact it apparently shows that the varietal replacement has slowed down in the 1990s. However, it is not unusual to experience relatively lower adoption and/or lower varietal replacement rate of newer MV within a short period after these MV were made available to the farmers. As empirically proved by Brennan and Byerlee (1991) based on adoption pattern of individual modern wheat cultivars in Australia, the adoption of a new MV is a dynamic process, which takes several years to reach maximum adoption level. Therefore, lower adoption rate of those MV that were developed and released in the 1990s (Table 2) does not necessarily imply that these MV are inferior to those MV that were developed and released before the 1990s (early MV). The average farmers yield of adopted MV that were developed and released over the GR period has remained roughly constant at approximately 4 tons per hectare (Table 2). However, there was a substantial improvement in grain quality and resistance to pests and diseases for the MV adopted in recent years. Approximately 60% of adopted MV have resistance to one or two insect pests or diseases that covered 55% of India s rice area (Table 3). Furthermore, MV with slender grain quality (better grain quality) were planted in approximately 63% of country s rice area that corresponds to increasing demand for high quality rice over the period (Table 4).

9 198 the developing economies TABLE 5 Area Planted to Modern Varieties (MV) of Rice and Their Concentration Ratio in Different Indian States, State Number of MV Adopted Area Planted (Million ha) Area Planted as % of State s Rice Area Area Planted as % of India s Rice Area Andhra Pradesh Karnataka Tamil Nadu Kerala Southern Region Punjab Haryana Uttar Pradesh Northern Region Assam Bihar Madhya Pradesh Orissa West Bengal Eastern Region Maharashtra Gujarat Western Region All India Source: Compiled from the respective state Departments of Agriculture. Sum of those states that were indicated above. C. Inter-regional Spillovers and Their Effects on Adoption As some of the MV were adopted in more than one state, the total number of MV is calculated to be 309 at all-india level (Table 5), even though the actual total is Nearly one-third of total adopted MV were distributed in the rainfed region of eastern India, covering approximately one-fourth of the country s rice area. The remaining two-thirds were largely dominated by irrigated ecosystem (Table 5). During , the coverage of MV reached 81% of total rice area in India. Interestingly, adoption rate of MV in eastern India reached nearly 78% of total rice area, despite the fact the average yield in this region is by far below the level for the rest of the country because of the unfavorable production environments. 3 Note that about 30 MV like Swarna, IR 64, IR 36, etc. were grown in more than one state. Since adopted MV were considered by state-wise, these MV were accounted for more than once depending upon the number of states in which they were grown during the period ( ). Although the actual number of adopted MV was only 221 as shown in Tables 3 and 4, the total number of adopted MV in all states together has become apparently 309 (Table 5), because some varieties were grown in more than one state.

10 modern rice varieties in india 199 TABLE 6 Area Planted to Adopted Modern Varieties (MV) in Indian States by Source of Their Origin, State Area Planted to MV (million ha) Percent Contribution from Same State Other States ICAR International Source Andhra Pradesh Karnataka Tamil Nadu Kerala Southern Region Punjab Haryana Uttar Pradesh Northern Region Assam Bihar Madhya Pradesh Orissa West Bengal Eastern Region Maharashtra Gujarat Western Region All India Source: Complied from various reports of ICAR (1992), CRRI (1996), DRR (2001) and compiled from respective state Departments of Agriculture. ICAR = Indian Council of Agricultural Research. Includes MV Introduced from International Rice Research Institute and other Countries. Total of those states that were indicated in this table. The MV grown in particular Indian states are not exclusively those developed in the same state. In some cases, the popular varieties with farmers are those MV developed and released in other states. Table 6 summarizes the inter-state/regional movement (domestic spillovers) of MV from one state to others. At the countrylevel, only 38% of total MV area was planted by MV developed in the same state, whereas those MV that were developed in other states and national research institutions in India, such as the Indian Council of Agricultural Research, covered approximately 41% of MV area. The direct releases of the International Rice Research Institute s breeding material covered about 21% of total MV rice area in India. The most important finding from this table is that about one-third of MV area in the eastern India was planted to those MV that were developed in other regions, largely in the irrigated ecosystem of South India. Although the eastern region is the biggest gainer of MV from other regions, western and northern regions also gained. These findings suggest that the rice MV developed for irrigated ecosystems especially of

11 200 the developing economies South India have also benefited substantially the eastern India through domestic spillovers. Most of MV were adopted in the rainfed-dominant eastern India through domestic spillovers especially after mid-1980s in areas where shallow and tube-well irrigation facilities were created. IV. PRODUCTIVITY GROWTH AND INSTABILITY The long-term trends in growth of rice yield and TFP and instability indices were computed for two different periods, namely, the early GR period ( ) and the late GR period ( ), to examine changes that took place between these two periods. 4 A. State-Level Trends in Yield Growth and Input Uses In contrast to the studies based on controlled environments cited earlier, the long-term growth trends of yields show an increasing trend throughout the GR period in Andhra Pradesh, Tamil Nadu, Karnataka, and Punjab (irrigated ecosystem), which were the forerunners of the rice GR in India (Table 7). However, growth TABLE 7 Compound Annual Growth Rates of Yield for Rice in Major States of India State Irrigated Area Ratio in 1999 (%) Annual Growth Rate of Yield (%) Andhra Pradesh Tamil Nadu Karnataka Punjab Uttar Pradesh Assam Bihar Madhya Pradesh Orissa West Bengal All India Source: Compiled from respective state Bureau of Economics and Statistics. 4 Total period was divided into two sub-periods for TFP and instability analyses, namely, (early GR period) and (late GR period). The reasons for choosing 1984/85 as a cut-off point are a) nearly 100% area of rice and wheat crops was covered with MV and irrigation by the mid-1980s in the favorable irrigated environments. Further, incremental increase in input use levels has considerably declined between 1985 and 2000 as compared to early GR period in this region; b) MV adoption has picked tremendously in the rainfed ecosystems after the 1985; c) many earlier studies reported either stagnation or decline in rice productivity after the mid-1980s; and d) India achieved self-sufficiency in food production during 1983 because of GR technologies.

12 modern rice varieties in india 201 TABLE 8 Trend in Input Use Levels for Rice in the Selected States of India State Andhra Pradesh: MV area (%) Organic manure (ton/ha) Chemical fertilizer (kg/ha) Labor (mandays/ha) TFP growth (%) Punjab: MV area (%) Organic manure (ton/ha) Chemical fertilizer (kg/ha) Labor (mandays/ha) TFP growth (%) Bihar: MV area (%) Organic manure (ton/ha) Chemical fertilizer (kg/ha) Labor (mandays/ha) TFP growth (%) West Bengal: MV area (%) Organic manure (ton/ha) Chemical fertilizer (kg/ha) Labor (mandays/ha) TFP growth (%) Source: Compiled from GIO-MOA (various years). MV = modern rice varieties; TFP = total factor productivity. rate of rice yields slowed down in the 1990s in these states as MV adoption became nearly complete, even though it did not become negative. There was also less increase in input uses in the 1990s as compared with the 1970s and 1980s in the irrigated states (Table 8). Furthermore, a cross-ecosystem yield trend shows that yield advances in rice started to increase at slower rate in intensive irrigated rice systems in the 1990s, whereas rainfed ecosystems have increased during the late GR period (Figure 1). It is, however, not unusual to reach yield plateau or deceleration in its growth in the progressive areas because the technology has reached its own potential ceiling beyond which yield levels cannot be increased easily (Pingali, Hossain, and Gerpacio 1997). The states such as Assam, Bihar, Madhya Pradesh, and West Bengal, which were predominantly rainfed areas, have picked up with quantum jump in the growth of rice yields in the 1980s (Table 7). Yield growth, however, has substantially slowed down even in some rainfed states during the 1990s. For the country as a whole, yield

13 202 the developing economies Fig. 1. Trends in Rice Yield for Irrigated and Rainfed Ecosystems, India, of rice has increased at annual compound growth of 2.3% during , with maximum growth achieved in the 1980s. Use of chemical fertilizer per unit of cropped area has substantially increased in irrigated states such as Andhra Pradesh and Punjab during the early GR periods, as MV area expanded rapidly. This also accompanied appreciable TFP growth (Table 8). The eastern India states, such as Bihar and West Bengal, which are predominantly rainfed states, have picked up after the 1980s with increased MV adoption. B. TFP Growth As stated in Section II, time-series data ( ) on quantities and prices of all major inputs, and output compiled from the reports of Cost of Cultivation of Principal Crops were used to estimate TFP growth for the selected major states of India. Table 9 reports growth rates of TFP during the early and late GR periods for major selected states. The TFP growth for rice was significantly higher in Punjab than in any other states during the early GR period; however, it slowed down drastically during the late GR period. However, output growth also declined rapidly between the early and late GR periods in Punjab, implying that the TFP growth was a principal source of output growth in this state. In Andhra Pradesh, which is also the forerunners of rice GR, the TFP grew at an average rate of 1.3% per annum during the entire GR period. The estimates of TFP growth in this study are closely comparable with earlier studies (Kumar and Mrithyunjaya 1992; Rosegrant and Evenson 1992, 1993; Kumar and Rosegrant 1994; Fan, Hazell, and Thorat 1998).

14 State modern rice varieties in india 203 TABLE 9 Total Factor Productivity (TFP) Growth of Rice in Principal Growing States (% per year) Period Output Growth Input Growth TFP Growth Andhra Pradesh Early GR Late GR Overall GR Karnataka Early GR Late GR Overall GR Punjab Early GR Late GR Overall GR Uttar Pradesh Early GR Late GR Overall GR Assam Early GR Late GR Overall GR Bihar Early GR Late GR Overall GR Madhya Pradesh Early GR Late GR Overall GR Orissa Early GR Late GR Overall GR West Bengal Early GR Late GR Overall GR Source: Compiled from GIO-MOA (various years). GR = Green Revolution. While fertilizer use for rice rapidly increased in Punjab, labor use substantially declined between the 1970s and 1980s (Table 8) because of mechanization of agriculture in Punjab. Therefore, higher rate of MV adoption, increased use of fertilizers, and irrigation expansion seem to be primary factors for TFP growth until the mid-1980s. Since TFP did not grow after the mid-1980s, increased input uses were the main factors that can contribute to output growth in Punjab as well as in Andhra Pradesh. In contrast, TFP growth picked up in Bihar and Orissa (largely rainfed states) as MV adoption increased after the 1980s in these states. In partially irrigated states such as Uttar Pradesh and West Bengal, TFP continued to increase, but it slowed down somewhat in the late GR period as compared with the early GR period (Table 9).

15 204 the developing economies TABLE 10 Instability Indices of Farm-Level Yields for Rice in Selected States, India (%) States Andhra Pradesh Punjab Bihar West Bengal Source: Compiled from GIO-MOA (various years). C. Has Green Revolution Increased Instability in Crop Yield? One of the arguments by the critics of GR was that GR technology has brought new production risks that led to rice production being more unstable than in pre-gr period (Dantwala 1987). One of the hypotheses in the current paper is that the development and adoption of MV with improved traits, such as increased resistance to pests, diseases, salinity, and drought, has stabilized the crop yields by reducing production risks over the period. To test this hypothesis empirically, instability indices were estimated for farm-level yields of rice separately for the early and late GR periods in the selected states. The estimates of instability indices (Table 10) clearly show that crop yields have been more stabilized, particularly in Punjab and Andhra Pradesh between the early and late GR periods where improved GR technologies were adopted rapidly and extensively. There was also an appreciable decrease in instability of yield between the early GR and post-gr periods in such rainfied states as Bihar and West Bengal as well, although instability indices are higher in these states than in Punjab and Andhra Pradesh during the late GR period. The expanded coverage of improved MV after the mid-1980s was likely to contribute to reduction in yield instability in Bihar and West Bengal. To sum up, yield instability might be higher at the initial stage of technology adoption because resistance to a variety of biotic and anti-biotic stresses can be incorporated to MV gradually over time. Therefore, yield tends to be stabilized during the later stages as experienced most notably in Punjab. Thus, instability of crop yield has declined gradually under irrigated agriculture followed by rainfed agriculture, where a series of new improved MV were adopted. V. CONCLUSIONS There were phenomenal increases in yields of rice in India especially under favorable irrigated environments over the past three decades of the GR. However, some studies indicated either declining or stagnation in yield of the intensive irrigated rice

16 modern rice varieties in india 205 systems largely based on experiments under controlled environments. However, yield growth is not a true measure of technology impact, as it does not net out the effect of input growth from output growth. The TFP growth is more appropriate measure of productivity impact of technical change. Therefore, the current paper analyzed the long-term yield growth in comparison with TFP growth by applying Tornqvist-Theil index method for the two periods, namely, (early GR) and (late GR), for major rice-growing states of India. It is found that MV with improved traits were increasingly and widely adopted by farmers, which is likely to be a chief source of TFP growth during the late GR period in the irrigated states. Although the long-term yields show an increasing trend throughout the GR period in irrigated states where MV adoption was nearly complete, it is also true that yield growth slowed down in the irrigated ecosystems in the 1990s. In contrast, rainfed ecosystems have picked up during the late GR period. In partially irrigated states such as Uttar Pradesh and West Bengal, TFP continued to increase, but it slowed down to some extent in the late GR period as compared with early GR period. The inter-state or inter-regional movement of MV from one state to another through coordinated rice-breeding network indicates spillover benefits from irrigated to rainfed states where new irrigation sources, such as shallow and tube wells, were created. Indeed, such varietal movement seems to have contributed to increased TFP growth in ranifed states such as Bihar, Orissa, and West Bengal after the 1980s. This strongly suggests that the MV of rice developed originally for irrigated ecosystems have also benefited substantially the rainfed dominant eastern Indian states through spillover benefits where partial irrigation facilities were made available. Therefore, it is a mistake to assume that the GR bypassed unfavorable rainfed areas. So far as such spillover effects exist, the GR technology eventually confers benefits to poor farmers in unfavorable areas. Thus, the strategy to develop technologies first for favorable areas can be justified not only on the efficiency ground but also on the equity ground. In our view, this might be an important lesson that sub-saharan African countries can learn from the Asian experience, if they want to realize a Green Revolution in generally unfavorable production environments. REFERENCES Brennan, J. P., and Derak Byerlee The Rate of Crop Varietal Replacement on Farms: Measures and Empirical Results for Wheat. Plant Varieties and Seeds 4, no. 1: Cassman, K. G., and Prabhu Pingali Extrapolating Trends from Long-Term Experiments to Farmers Fields: The Case of Irrigated Rice System in Asia. In Agricultural Sustainability; Economic, Environmental and Statistical Considerations, ed. Vic Barnett, Roger Payne, and Roy Steiner. Chichester: Wiley. Central Rice Research Institute (CRRI) Miracle Rice Varieties. Cuttack: CRRI. Dantwala, M. L Growth and Equity in Indian Agriculture. Indian Journal of Agricultural Economics 42, no. 2:

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