Research and Pioduciiviiy in Wheat and Maize: An Inicrnaiional Analysis 



67 



Table 4.2: Wheat: Yield Regressions (Equation 4.13, 

 Logistic Borrowing Function 4.7) 



Regression 



R^ 

 Constant 



1. Area (A) 



2. Time (t) 



3. Own 

 research 

 [K(t)\ 



4. Borrowed 

 knowledge 

 [B(t)] 



1. Area: 



2. Time: 



3. Own research K(r): 



Notes: 

 No. of observations: 1,316 (64 countries, 21 years, 28 missing observations) 

 Variables: 



Dependent: Average yield, 100/kg per hectare 

 Independent: 



wheat area in '000 hectares 

 the year /, f = 1, 2, . . . 21 



sum of counts of Plant Breeding Abstracts from 1948 

 to year t 

 4. Borrowed knowledge:fl//>) as defined in equations 4.7,4.8 

 Country dummies: 63 country-dummy variables included in all regressions to 

 represent variable 5 in equation 4.13 

 Deflator: 

 regression 1 area deflator, regression 2 K(t), p(t), regional deflator 

 regression 3 K(t) area, B(tJ, p(t) regional deflator 

 regressions 4, 5 none 

 Country dummies included in all the regressions a, |3 values were estimated in 

 regressions 1 and 4. 

 In parentheses: / values 



The results in table 4.1 indicate positive relations between 

 research and yield increases both in wheat and in maize. With the 



