THESIS

Confirmation of interspecific hybrids
2.1 Pollen fertility
To confirm that the putative hybrid obtained were truly of interspecific,
pollen fertility analysis was performed at flowering stage. Since interspecific and
intergeneric hybrid sterility has been reported as a general hybrid barrier in many
crops, pollen viability was tested (Yoon, 2003). Almost all pollen grains of
interspecific hybrid were not stained by acetocarmine and the size was smaller than
their parent (Figure 12).
According to Behera and Singh (2002a; 2002b) who reported that the
sterility is typically due to the disharmonius genetic consititution or combination of
genes of the hybrids with different types of earliest differentiation to the final stage of
meiosis.
The pollen fertility of intra- and inter-specific hybrids between S.
melongena and its wild relative, and their respective parents were showed in Table 20.
The intraspecific hybrids within S. melongena had higher pollen viability than the
interspecific hybrids between S. melongena and S. torvum (0.00 %). This result
indicate that the F1 hybrids within S. melongena had high pollen viability due to the
species with closely related genetic affinity produce fertile hybrids with regular
chromosome pairing, while the hybrids of those more distantly related species have
meiotic irregularities and are sterile (Marfil et al., 2006).
However, the pollen fertility of interspecifc hybrids between S. melongena
x S. americanum (61.09 %), S. melongena x S. villosum (74.23 and 73.50 %) and S.
melongena x S. nigrum (72.88 %) had high pollen fertility than S. melongena x S.
torvum (0.00 %). This result indicated the hybrids from those species were not true
interspecific hybrids because all pollen grains of interspecific hybrid were not stained
by acetocarmine and the size was smaller than their parents (Yoon, 2003). According
to Gowda et al. (1990), hybrids between S. melongena x S. macrocarpon are sterile,
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