THESIS

Moreover, genetic diversity has an important role in plant breeding programs.
The loss of genetic diversity, in part due to the conventional breeding programs
associated with modern agricultural practices, has been dramatic in many cultivated
species (Wilkes, 1983). In consequence, the narrow genetic base of the elite
germplasm has increased the potential vulnerability to pests and abiotic stress.
Therefore, the wild relatives and even alien species are needed to broaden the genetic
bases of breeding program through interspecific hybridization (Stoskopf, 1993).
Therefore, plant breeders can succeed their breeding programs by relying on the
diversity or variation in plant populations. A comprehensive understanding of the
amount and pattern of genetic variation that exists within and between the available
cultivated and wild accessions is important for enhancing genetic potential because
the diverse germplasm may include traits needed for effective improvement of the
crop (Seehalak, 2005). Moreover, plant diversity study also reveals the relationship
among plants in a population which guides the researcher to understand their
evolution, indicates the centers of origin (Xu-xiao et al., 2003).
Germplasm collections are assembled and maintained primarily because of
their potential use in crop improvement in the present and in the future. Additionally,
the collection aims to provide a broad genetic base from which plant breeders can
obtain desirable genotypes. Therefore, for the materials in the genebank to be of
interest to the breeder, characterization and evaluation data should be available
(Engle, 1992).
Characterization and evaluation are required to identify the desirable
germplasm for utilization as well as to avoid duplication in management efforts
(Engle, 1992). The role of characterization and evaluation in the utilization of genetic
resources is recognized and need to be more clearly understood. The curator’s
responsibilities are maintained and characterize a collection, to assemble the
information resulting from all parts of the process and to transmit it to the data banks
(Islam, 1992). Moreover, evaluation is the essential link between conservation and
use. For a better utilization, evaluation must be related to the breeder or consumer
needs. Usually these are characters related to high yield, resistance to pests and
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