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The Diffusion of High Yielding Varieties of Rice and Wheat in Pakistan: 

The Diffusion of High Yielding Varieties of Rice and Wheat in Pakistan Qazi T. Azam Robert E. Evenson

Research Questions: We plan to address four questions for each crop.: 

Research Questions: We plan to address four questions for each crop. What factors determined the date of origin of HYV diffusion in different districts? What factors determined the rate of HYV diffusion in different districts? What factors determined the level of yields on land where farmers adopted HYV’s? What factors determined the level of yields on land where farmers did not adopt HYV’s?

Specifications:A. The Origin Specification:: 

Specifications: A. The Origin Specification: For both crops we specify the dependent variable as: PctHYV69: The percent of area in the district in 1969 planted to HYVs.

The independent variables are:RMLiteracy, RdHiType, MktDist0To5Km, MktDistOver 5Km,YTrad69,YRatio69 : 

The independent variables are: RMLiteracy, RdHiType, MktDist0To5Km, MktDistOver 5Km,YTrad69,YRatio69 Where: RMLiteracy: The percent of rural adult males with literacy (based on census data). RdHitype: The ratio of length of “High Type” paved roads to the cropped area (all crops) in the districts. MktDist0To5Km: The number of markets within 0 To 5 kilometers of the average district farm. MktDistOver5Km: The number of markets greater than 5 kilometers from the average district farm. YTrad69: The Average Yield (1969-70 to 1970-71) of Traditional (Non-HYV) varieties in the district. YHYV69: The Average Yield (1969-70 to 1970-71) of HYV varieties in the district. YRatio: YHYV69/YTrad69.

For the wheat specification we added:: 

For the wheat specification we added: PctIrrig69: The percent of wheat crop irrigated in 1969

For the rice specification we added:: 

For the rice specification we added: PctBasmati69: The percent of the rice crop planted to Basmati varieties in 1969

Slide7: 

Table 1. Variable Summary and Means

Slide8: 

Table 1. Variable Summary and Means (cont..)

Slide9: 

Table 2. Estimates: Origin Specifications

Origin Estimates:: 

Origin Estimates: Earlier HYV Adoption with Higher Farm Literacy. Wheat: Better Production Conditions. Rice: Better Basmati Production Conditions.

B. The Rate of Diffusion Specification: : 

B. The Rate of Diffusion Specification: We recognize the “S-shaped” nature of adoption by defining our dependent variable in the rate specification as: LogHYV = ln (PctHYV/100-PctHYV) This variable is defined over all years, 1969 to 1998

The independent variables are:: 

The independent variables are: RMLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM Where: Each of these variables is defined for each year. In addition we added a variable (ResExpend, a research stock variable based on real research expenditures) that varies by year and province (Punjab & Sind).

The origin variables are also included in the rate specifications : 

The origin variables are also included in the rate specifications These are PctHYV69, YTrad69 and YRatio. For the wheat specification we also included PctIrrig69 For the rice specification we included PctBasmati69.

Slide14: 

Table 3. Estimates: Diffusion Rate Specification

The diffusion rate estimates for wheat indicate that: : 

The diffusion rate estimates for wheat indicate that: Higher farmer literacy rates accelerate diffusion Higher levels of investment in wheat research accelerate diffusion. Favorable production conditions, as reflected in the YTrad69, YRatio69, and PctIrrig69, accelerate diffusion. Road condition and market condition do not accelerate diffusion.

The diffusion rate estimates for rice indicate that:: 

The diffusion rate estimates for rice indicate that: Higher farmer literacy accelerates diffusion. Higher levels of investment in rice research accelerates diffusion. Higher yield advantage (YRATIO) accelerates diffusion Favorable conditions for Basmati production accelerates diffusion Road and Market conditions do not affect diffusion.

C. The Yield Specifications: : 

C. The Yield Specifications: For the yield specification the dependent variables are: YHYV: The district average yield on area planted to HYV’s. And, YTrad: The district average yield on area planted to Traditional Varieties (This does not include Basmati Varieties for Rice). The independent variables in these specifications are: RMLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM and ResExpend. The origin yield variables are also included in this specification

Slide18: 

Table 4. Estimates: Yield specifications

The wheat yield estimates indicate: : 

The wheat yield estimates indicate: That farmer literacy is associated with higher yields for both Traditional and HYV’s. That better roads and market conditions have little net effect on yields, except that market conditions favor HYV yields (possibly through better access to inputs). That research programs contribute to higher yields for both Traditional and HYV production. This attests (along with the literacy results) to contributions from research programs other than genetic improvement capacity (agronomy, management etc).

The wheat yield estimates indicate: (Continued): 

The wheat yield estimates indicate: (Continued) That conditions associated with origin HYV adoption (PctHYV69) indicate that traditional variety production did get crowded on to less favorable production conditions. That initial irrigation conditions favored traditional varieties.

The rice yields estimates indicate:: 

The rice yields estimates indicate: That production condition favoring 1969 adoption favored subsequent yields of both traditional and HYVs. That rice research favored HYV yields. That market and road conditions had little impact on yields

Simultaneous Equations specifications:: 

Simultaneous Equations specifications: The purpose of the simultaneous equations is to consider the dynamics of the relationships between HYV adoption and yields. The single equation estimates do not capture this relationship, except to the extent that 1969 levels of HYV adoption has lasting effects on later adoption.

For wheat, there is a relationship between HYV adoption and irrigation : 

For wheat, there is a relationship between HYV adoption and irrigation The Wheat system is a four equation system with endogenous variables noted by an asterisk: LogHYV*: PctIrrig*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, PctHYV69,YTrad69, YRatio. PctIrrig*: LogHYV*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, PctIrrig69,YTrad69, YRatio. YTrad*: PctIrrig*, LogHYV*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, YTrad69. YHYV*: PctIrrig*, LogHYV*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, YHYV69.

For rice, irrigation is not an issue, since all rice is effectively irrigated, but competition with Basmati Rice is important: : 

For rice, irrigation is not an issue, since all rice is effectively irrigated, but competition with Basmati Rice is important: The rice model is a five equation model (with endogenous variables noted by an asterisk). LogIRRI*: PctBasmati* RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, PctIRRI69, YTrad69, YRatio. LogBasmati*: LogIRRI*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, PctBasmati69, YTrad69, YRatio. YTrad*: PctBasmati*,LogIRRI*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, YTrad69. YBasmati*: PctBasmati,* LogIRRI*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, YBasmati69. YIRRI*: PctBasmati*, LogIRRI*, RmLiteracy, RdHiType, MktDist0To5Km, MktDistOver5KM,ResExpend, YIRRI69.

Slide25: 

Table 5 Simultaneous Equation Specification (3 stage Least Square) (Continued)

Slide26: 

Table 5 Simultaneous Equation Specification (3 stage Least Square). Conti….

Slide27: 

Table 5 Simultaneous Equation Specification (3 stage Least Square).

Simultaneous Equation Estimates for Wheat Shows:: 

Simultaneous Equation Estimates for Wheat Shows: HYV adoption stimulates irrigation. Irrigation stimulates HYV adoption. Literacy stimulates HYV adoption Better Roads & Markets stimulate irrigation. Wheat Research stimulates HYV adoption, irrigation and yields. HYV adoption impacts on wheat yields.

Slide29: 

Table 6 Simultaneous Equation Specification (3 stage Least Square) Cont...

Slide30: 

Table 6 Simultaneous Equation Specification (3 stage Least Square).

Simultaneous Equation Estimates for Rice Indicates:: 

Simultaneous Equation Estimates for Rice Indicates: Basmati area competes with IRRI area. Literacy stimulates IRRI and Basmati diffusion. Rice research stimulates IRRI and Basmati diffusion. IRRI adoption raises Basmati yields and Traditional varieties yields

Conclusions:: 

Conclusions: Determinants: Date of Origin - Higher farmer literacy Wheat: Better Production Conditions Rice: Better Production Conditions for Basmati.

Conclusions: (Continued): 

Conclusions: (Continued) Determinants: Diffusion - Higher Farmer Literacy - Higher Crop Research Investment - Favorable Production Conditions

Conclusions: (Continued): 

Conclusions: (Continued) Determinants: HYV Yields - Higher Literacy (Wheat) - Higher Research Investment - HYV Adoption Raises Yields

Conclusions:: 

Conclusions: Determinants: HYV Yields - Higher Literacy (Wheat) - Higher Research Investment - Roads & Markets: Small Impact