Introduction

Abstract

Rice is the most important tropical cereal and supplies a quarter of the entire caloric intake of the human race. It is the staple food of more people than any other crop and 90 per cent is grown and consumed in South and Southeast Asia, which are major centres of the world’s population. Rice belongs to the genus Oryza and there are two main cultigens: sativa in Asia and glaberrima in Africa. It is a semi-aquatic graminaceous crop of great diversity: there are probably more cultivars of rice than of all the other food grains put together. As early as 1891, Watt estimated that about 10 000 rice cultivars were grown in Undivided Bengal alone. Rice is also unique in that it has become established in a greater and more complex range of environmental conditions than any other crop — from upland rice at altitudes of 3000 m, to rain-fed lowlands, irrigated areas, tidal swamps and, finally, the deepwater areas which are the subject of this book.