28 SOCIAL SCIENTIST one might say it has been predicated on a relative decline in basic food production. This is because, to the extent that irrigated and fertile land as well as capital is restricted and there is competition for its allocation between different types of crops, the success of the non-staple crops has necessarily to be at the expense of the staples; the 'success* of the non-staples is in turn related to the whole complex of profitability conditions and government policies in operation at various times. In the case of the Latin American developing countries, de Janvry (1981) finds a systematic tendency during the period of green revolution from the late fifties onwards, of a decline in the growth-rates of what he calls the *wage-goods1 portion of agricultural products, of which the most important is basic foodgrains, relative to the growth-rates of commercial crops; this has translated in many cases into a decline in the per capita production of staple foodgrains, compared to a vigorous growth of products for export to the metropolitan centres both at the national and at the world level. As a result a marked dualism has emerged within the agriculture of these countries between a dynamic capitalist sector producing in one way or another for export and a peasant subsistence sector with stagnant yields and falling output per head. The reason for these common patterns have to do with the superior purchasing power vis-^-vis third world agriculture, of the metropolitan centres, which we may think of as having two highly unequal segments of varying weight. The domestic metropolitan centres comprise the non-agricultural sector of the national economy concerned; this is not exactly, but is substantially conterminous with the urban sector of the economy. The international metropolitan centre is more powerful, by several dozen multiples in terms of purchasing power, than the domestic metropolitan centre, and if the third world economy concerned relaxes protectionism and liberalises trade and the entry of foreign capital, the suction effect of the immensely larger purchasing power of the international metropolis is felt in a more or less rapid alteration of the agricultural production structure in the direction required to satisfy the needs of the metropolis. This process enriches the domestic capitalist producers who in collaboration with the MNCs are the instruments of this alteration in the cropping structure, and at the same time precipitates a crisis of livelihood for the ordinary mass of the peasantry and labourers. The predominance of international metropolitan purchasing power also tends to affect adversely most of the domestic metropolitan population by a relative displacement of and therefore higher costs of basic staple crops, and through lowered domestic availability of and higher prices of a range of specialised goods in increasing foreign demand. Students of development not only in the western countries but also in the affected third world countries often see nothing to be concerned