CHAPTER ONE
INTRODUCTION  
Rice is a staple food for more than 60 percent of the world’s population (Richardson and Stubbs, 1978). Rice has become a staple food crop of considerable strategic importance in many rapidly growing African countries where consumption among the urban poor household has increased substantially (WARDA, 1993).  Cultivated rice is designated as either oryza sativa or oryza glabberima, oryza sativa is the predominant species. “Oryza glabbenma is grown only in Africa” on a limited scale.  The rapid rise in rice production in the years, following world was 11, mainly in Asia, stemmed from expanded irrigation areas, the increased use of fertilizers, effective control of pests, double rice cropping, and the widespread adoption of improved genetic materials. The combined use of nitrogen fertilizers and use of high-yielding varieties has made possible the expression of high yield in irrigated areas. Varieties of short growth duration which are insensitive to the photoperiod have allowed year round planting and multiple cropping.  The adoption of semi-dwaft high yield varieties triggered the beginning in 1967: Chinese farmers also turned to the utilization of the semi-dwaft varieties. The development of hybrid rice in China since the 1970s has set off a second “Green Revolution” in that area.  New genetic information and genetic diversity provide the foundation for more efficient breeding programs for rice production. It remained for the simply inherited recessive gene (Sdi) in the Chinese semi-dwaft rice to provide rice breeders with the impetus to achieve further progress in rice breeding.   
1.1 RICE GRAIN QUALITY INDICATORS   The most important factors that plant breeders consider in developing new rice varieties are grain quality and yield. The term “grain quality” has many meanings and is perceived differently defending on end use, field of interest, specialization and ethnic importance as a quality characteristic, rice millers emphasize processing quality: and consumers demand a widely divergent array of cooking and eating qualities.  Quality in rice may be categorized into four broad areas:   Milling quality   Cooking and processing quality   Nutritive quality   Specific standards for cleanliness, soundness and purity.  All four (4) categories are important in judging the suitability of rice for a specific use. The quality characteristics desired vary considerably, being ultimately related to final consumer acceptance of each rice product.  Characteristics that influence rice quality include those under genetic control and those independent of genetic control, such as purity and cleanliness. These latter characteristics are primarily a function of handling and storage and as such are described thoroughly in United States standards for rice and in the rice inspection handbook.  A major factor influencing rice quality is the environment in which the plants are grown. Once a new variety is released for commercial production, it spreads to wherever it can be produced advantageously compared to currently grown varieties. Consequently, before released, new varieties are tested agronomical and for quality over their likely production area.  Tests are carried out in rice performance nurseries in each rice producing state. These trials permit evaluating quality characteristics of new varieties over wide ranges of environmental influence such as soil, climate and cultural practices.  Characteristics Influencing Qualities in Rice Include:  Hull and pericarp colour   Grain-shape, weight, uniformity, and general appearance   Milling cut turn.  Kernel, chalkiness, translucency and colour and cooking, eating and processing characteristics.