National Academy for Agricultural Research Management Hyderabad India2Department of Economics Yale University New Haven Connecticut USA

From 1967 to 1991 rice production in India grew by 2.82% per year. Area planted to rice grew by 0.58% per year and rice yields grew by 2.28% per year. Yield increases were the result of increased input use (including irrigation) and the adoption of modern rice varieties. The classification of 'modern varieties' has not been constant over time as rice breeders have incorporated new traits into modern rice varieties. In this chapter we report estimates of the economic value of several of these traits using data from farms in India.

In earlier work, Gollin and Evenson (Chapter 9) applied hedonic evaluation methods to district production data where estimates of the genetic resource content of rice varieties were available. An alternative and more direct procedure for evaluating trait values is to utilize data on actual varietal yields in the field. The ideal data set would be produced by a controlled experiment where natural factors including disease and insect susceptibility were held constant. Such data do not exist but can be approximated in the two data sets that are used in this study.

The first data set is compiled by ICAR for selected districts and years. ICAR reports yields for the three 'highest yielding' varieties in farmers' yield trials in each district-year combination for irrigated and unirrigated, kharif and rabi season rice. Fertilizer use is controlled and yields are reported for a sample of farms in the district. Each variety can be given trait characteristics and hence yields can be related to these characteristics. This data set is available for the years 1977-1989, covering some 45 districts in India. The weakness of these data is that the sample size of three is not large enough to provide an adequate control group. Furthermore, it is a highly selected reference group. It is plausible that the district average yield for the year in question and other district-level variables might represent a control group. Thus if poor weather affects the district average, it should affect the top three varieties as well, or if pest incidences were severe it could have affected all varieties. But it is also possible that the ICAR sample was representative of the district.

The second varietal data set is more promising. These state-level data are reported by state departments of agriculture and by the state Directorate of Economics and Statistics for different years. For each state-year combination, all important varieties planted are included in the data set. Yields from crop-cutting experiments carried out on farmers' fields are reported in this data set. The data set covers the five states of Punjab, Haryana, Andhra Pradesh, Tamil Nadu and Karnataka. For these data, one can use the yields of other varieties in the state as a reference group. Thus for a given year the yield of varieties with a particular trait can be compared with the yields of all varieties in the state. Weather, insect and disease problems, etc., can be considered to have influenced all varieties equally.

0 0

Post a comment