THESIS

Moreover, an accurate determination of genome size provides basic
information for breeders and molecular geneticists. Comparisons of nuclear DNA
amount were also useful in cytotaxonomy and evolution. Beacause of its rapid and
simple, DNA flow cytometer has become a popular method for ploidy screening,
detection of mixoploidy and aneuploidy, cell cycle analysis, assessment of degree of
polysomaty, determination of reproductive pathway and estimation of absolute DNA
amont to determine size. Therefore, ploidly level determination was useful to confirm
hybridity of interspecific hybrids. However, a major drawback to ploidy identification
using bulk samples is that bulk samples may mask the presence of aneuploid plants
(Lee and Lin, 2005).
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Therefore, the induction of polyploidy can overcome crossing barriers
resulting from endosperm failure. In intra-specific, intraploidy crosses, viable seeds
are produced because the endosperm develops normally. Conversely, in most interploidy
crosses, inviable seeds are produced as a result of endosperm failure. How ever,
endosperm may also fail to develop adequately in some intraploidy, interspecific
crosses, while some interploidy crosses succeed. Therefore, crossing success is
predicted by effective ploidy, rather that actual ploidy (Jansky, 2006).