Genetic diversity is critical to success in any crop breeding and it provides information about the quantum of genetic divergence and serves a platform for specific breeding objectives. It is one of the three forms of biodiversity recognized by the World Conservation Union (IUCN) as deserving conservation. Silkworm Bombyx mori, an economically important insect, reported to be domesticated over 5000 years ago by human to meet his requirements. Genetic diversity is a particular concern because greater genetic uniformity in silkworm can increase vulnerability to pests and diseases. Hence, maintenance of genetic diversity is a fundamental component in long-term management strategies for genetic improvement of silkworm which is cultivated by millions of people around the worlds for its lusture silk. In this paper genetic diversity studies carried out in silkworm using divergent methods (quantitative traits and biochemical and molecular markers) and present level of diversity and factors responsible for loss of diversity are discussed. 1. Introduction Sericulture is a unique field of agriculture, because silkworms are reared on an extensive scale in rearing houses and their silk cocoons are utilized as fine material for clothing. Like agriculture, sericulture also requires a continuous flow of productive silkworm breeds and host plant varieties to meet the ever-changing demand of people involved in the industry besides the consumer sector. To meet all these requirements, the breeder needs very wide and inexhaustible genetic resources to meet the ever-changing demands from various sectors. Considering the great economic importance of Bombyx mori, silk producing countries, such as China, Japan, India, Russia, Korea, Bulgaria, and Iran, have collected number of silkworm breeds suitable for a wide range of agroclimatic conditions. More than 4000 strains are maintained in the germplasm of B. mori and 46 institutes are involving silkworm genetic resources maintenance, which includes univoltine, bivoltine, and polyvoltine strains. These different genotypes display large differences in their qualitative and quantitative traits that ultimately control silk yield. It was estimated that silkworm genome consists of about 4.8′ 108？bp; its genetic information volume is about one-sixth of human being. There are over 450 morphological, physiological, and biochemical characters recorded at present, among them 300 (including multiallele) had been located on 27 groups of the total 28 chromosomes [1]. Apart from a rich biodiversity of geographical races, there are also a large
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