STUDIES ON GENE FREQUENCIES OF POLYEMBRYONY AND KARYOTYPE IN FLUTED PUMPKIN (Telfairia occidentalis Hook. F.)

Thesis Abstract

Five experiments were performed to investigate thepolyembryonic expressions and karyomorphology of fluted pumpkin(Telfairia occidentalis Hook. F.). The results obtained revealed threemorphotypes of polyembryony which included twin, triple andquadruple, irrespective of the shape of the pod. The threemorphotypes had side shoots that varied in length. Some wereunequal, a few of them were almost equal, and many hadrudimentary side shoots, which subsequently degenerated with time.Chi-square test between the pod shape and the embryo type depictedindependence (χ2= 1.02; P= 0.90) between pod shape and the embryotype. The triple and quadruple embryo types had the highest andlowest frequencies of occurrence, respectively. The gene frequenciesin the first year were 0.64 and 0.36 for polyembryony (S allele) andmonoembryony (s allele), respectively. The derived zygotic frequencieswere 0.41 for the homozygous dominant (SS); 0.46 for theheterozygous (Ss) and 0.13 for the homozygous recessive (ss). Thesesummed up to 0.87 for the multiple embryonic traits and 0.13 for thesingle embryonic trait. In the second year, the zygotic frequencies forthe homozygous dominant (SS), the heterozygous (Ss) and thehomozygous recessive (ss) were 0.33, 0.49 and 0.18, respectively.These corresponded with the 0.82 for the multiple embryonic traitsand 0.18 for the single embryonic trait. Chi square analysis showedthat the gene frequencies in both years did not differ significantly (χ2=0.017; P= 0.96). The results obtained from the cytological studies offluted pumpkin revealed the interphase and mitotic stages of the cellcycle, and a diploid chromosome number of 2n = 22. There weretraces of polyploids namely; aneuploids (2n = 22 + 1), triploid (3n =Five experiments were performed to investigate thepolyembryonic expressions and karyomorphology of fluted pumpkin(Telfairia occidentalis Hook. F.). The results obtained revealed threemorphotypes of polyembryony which included twin, triple andquadruple, irrespective of the shape of the pod. The threemorphotypes had side shoots that varied in length. Some wereunequal, a few of them were almost equal, and many hadrudimentary side shoots, which subsequently degenerated with time.Chi-square test between the pod shape and the embryo type depictedindependence (χ2= 1.02; P= 0.90) between pod shape and the embryotype. The triple and quadruple embryo types had the highest andlowest frequencies of occurrence, respectively. The gene frequenciesin the first year were 0.64 and 0.36 for polyembryony (S allele) andmonoembryony (s allele), respectively. The derived zygotic frequencieswere 0.41 for the homozygous dominant (SS); 0.46 for theheterozygous (Ss) and 0.13 for the homozygous recessive (ss). Thesesummed up to 0.87 for the multiple embryonic traits and 0.13 for thesingle embryonic trait. In the second year, the zygotic frequencies forthe homozygous dominant (SS), the heterozygous (Ss) and thehomozygous recessive (ss) were 0.33, 0.49 and 0.18, respectively.These corresponded with the 0.82 for the multiple embryonic traitsand 0.18 for the single embryonic trait. Chi square analysis showedthat the gene frequencies in both years did not differ significantly (χ2=0.017; P= 0.96). The results obtained from the cytological studies offluted pumpkin revealed the interphase and mitotic stages of the cellcycle, and a diploid chromosome number of 2n = 22. There weretraces of polyploids namely; aneuploids (2n = 22 + 1), triploid (3n =