Studies on gene frequencies of polyembryony and karyotype in fluted pumpkin (telfairia occidentalis hook. f.)

Thesis Abstract

Five experiments were performed to investigate the
polyembryonic expressions and karyomorphology of fluted pumpkin
(Telfairia occidentalis Hook. F.). The results obtained revealed three
morphotypes of polyembryony which included twin, triple and
quadruple, irrespective of the shape of the pod. The three
morphotypes had side shoots that varied in length. Some were
unequal, a few of them were almost equal, and many had
rudimentary side shoots, which subsequently degenerated with time.
Chi-square test between the pod shape and the embryo type depicted
independence (χ2= 1.02; P= 0.90) between pod shape and the embryo
type. The triple and quadruple embryo types had the highest and
lowest frequencies of occurrence, respectively. The gene frequencies
in the first year were 0.64 and 0.36 for polyembryony (S allele) and
monoembryony (s allele), respectively. The derived zygotic frequencies
were 0.41 for the homozygous dominant (SS); 0.46 for the
heterozygous (Ss) and 0.13 for the homozygous recessive (ss). These
summed up to 0.87 for the multiple embryonic traits and 0.13 for the
single embryonic trait. In the second year, the zygotic frequencies for
the homozygous dominant (SS), the heterozygous (Ss) and the
homozygous recessive (ss) were 0.33, 0.49 and 0.18, respectively.
These corresponded with the 0.82 for the multiple embryonic traits
and 0.18 for the single embryonic trait. Chi square analysis showed
that the gene frequencies in both years did not differ significantly (χ2=
0.017; P= 0.96). The results obtained from the cytological studies of
fluted pumpkin revealed the interphase and mitotic stages of the cell
cycle, and a diploid chromosome number of 2n = 22. There were
traces of polyploids namely; aneuploids (2n = 22 + 1), triploid (3n =
Five experiments were performed to investigate the
polyembryonic expressions and karyomorphology of fluted pumpkin
(Telfairia occidentalis Hook. F.). The results obtained revealed three
morphotypes of polyembryony which included twin, triple and
quadruple, irrespective of the shape of the pod. The three
morphotypes had side shoots that varied in length. Some were
unequal, a few of them were almost equal, and many had
rudimentary side shoots, which subsequently degenerated with time.
Chi-square test between the pod shape and the embryo type depicted
independence (χ2= 1.02; P= 0.90) between pod shape and the embryo
type. The triple and quadruple embryo types had the highest and
lowest frequencies of occurrence, respectively. The gene frequencies
in the first year were 0.64 and 0.36 for polyembryony (S allele) and
monoembryony (s allele), respectively. The derived zygotic frequencies
were 0.41 for the homozygous dominant (SS); 0.46 for the
heterozygous (Ss) and 0.13 for the homozygous recessive (ss). These
summed up to 0.87 for the multiple embryonic traits and 0.13 for the
single embryonic trait. In the second year, the zygotic frequencies for
the homozygous dominant (SS), the heterozygous (Ss) and the
homozygous recessive (ss) were 0.33, 0.49 and 0.18, respectively.
These corresponded with the 0.82 for the multiple embryonic traits
and 0.18 for the single embryonic trait. Chi square analysis showed
that the gene frequencies in both years did not differ significantly (χ2=
0.017; P= 0.96). The results obtained from the cytological studies of
fluted pumpkin revealed the interphase and mitotic stages of the cell
cycle, and a diploid chromosome number of 2n = 22. There were
traces of polyploids namely; aneuploids (2n = 22 + 1), triploid (3n =