Genetic Divergence, Implication of Diversity, and Conservation of Silkworm,Bombyx mori

Abstract

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.

Implications of genetic diversity in the improvement of silkworm Bombyx mori L.

“…Maqbool et al (2015) and Falconer and Mackay (1996) indicate that these results can be explained by the fact that populations, over time, have been differentiated by genetic drift and continuous artificial selection, being able to adapt morphologically and/ or physiologically to specific agroclimatic conditions which eventually led to divergence. Bindroo and Moorthy (2014) suggest that variation is affected by other evolutionary forces such as effective size of the population, mutation, gene flow, inbreeding depression and natural selection. In silkworm, it could be affected by domestication, genetic drift, inbreeding, and the breeding systems used.…”

“…According to Brown (1988), an enhancer selects elite parentals to obtain superior progenies, but the continuous use of the best genotypes reduces the genetic base, since only the alleles that come from these parents are available. Bindroo and Moorthy (2014) suggest that reduction also occurs when the breeder introduces wild-type alleles to their target genotype, because the process of "eliminating" "undesirable" alleles must be begun.…”

Genetic diversity of maize accessions for maizelethal necrosis disease resistance

“…PCR based molecular marker techniques have made it possible for breeders and other scientists to make genetic diversity estimates as generated through different molecular markers (Arif et al, 2010;Poczai et al, 2013). Genetic diversity results from the genetic variation among individuals and may be expressed in DNA sequences (Bindroo and Moorthy, 2014;Osawaru et al, 2015). It can be categorized in terms of the number of different alleles existing in different populations, distribution of those alleles in the chromosomes, the impact they have on performance and the general variability among different populations under various environmental conditions (Rao and Hodgkin, 2002;Mondini et al, 2009;Bindroo and Moorthy, 2014).…”

“…Genetic diversity results from the genetic variation among individuals and may be expressed in DNA sequences (Bindroo and Moorthy, 2014;Osawaru et al, 2015). It can be categorized in terms of the number of different alleles existing in different populations, distribution of those alleles in the chromosomes, the impact they have on performance and the general variability among different populations under various environmental conditions (Rao and Hodgkin, 2002;Mondini et al, 2009;Bindroo and Moorthy, 2014). Some of the techniques that have been applied in molecular studies include RFLPs (Mondini et al, 2009), RAPDs (Brown-Guedira et al, 2000Mondini et al, 2009), AFLPs (Mondini et al, 2009), SSRs (Kumari et al, 2005;Beyene et al, 2005;Mondini et al, 2009;Aci et al, 2013;Abraha et al, 2014).…”

Screening and classification of mulberry silkworm, Bombyx mori based on thermotolerance

“…Genetic diversity in silkworm is generally measured based on the phenotypic traits that have been used for differentiation of silkworm genotypes because most of the traits are either qualitative or quantitative (Bindroo and Moorthy, 2014). However, molecular markers are other types to estimate genetic diversity, which can provide a rapid means of analysis of genetic diversity in germplasm (Bindroo and Moorthy, 2014).…”