Browsing by Author "Egbucha, K.C."

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    DICENTRIC CHROMATID BRIDGES AND POLLEN STERILITY IN CLEOME GYNANDRA
    (Department of Plant Science and Biotechnology, Nasarawa State University, Keffi., 2017-01-18) Isa, Hauwa'u; Onovo, J.C.; Egbucha, K.C.
    The present investigation revealed that the haploid chromosome number of Cleome gynandra (Linn) is n=9 and 4n=36. It is essentially a tetraploid. Meiotic chromosome behaviour in pollen mother cells (PMCs) in this tetraploid at Anaphase I and II were highly irregular. The percentage of chromatid bridges observed during the course of investigation in this tetraploid species was found to be 40.35. In the present investigation the tetraploid species investigated showed 47.60% morphologically fertile pollens, and 52.40% morphologically sterile pollens. It appears that the high frequency of chromatid bridges formed (40.35%) and 52.40% pollen deformity seems to indicate that chromatid bridges were not beneficial to the ecological aptitude of the taxon with regards to its sexual reproduction as deformed pollens often are nonviable. From the results of the present investigation, it was clear that structural alterations in the chromosomes due to largely frequent bridge formation appeared to be part of a common factor contributing to the sterility of pollen grains in Cleome gynandra.
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    KARYOTYPE ANALYSIS IN ZEA MAYS L. VAR. EVERTA (POPCORN) CULTIVATED WITHIN OWERRI, SOUTHEAST NIGERIA
    (Department of Plant Science and Biotechnology, Nasarawa State University, Keffi., 2023-02-20) Egbucha, K.C.; Aghale, Duke Nduka; Isa, Hauwa'u
    Karyotype analysis of Zea mays L. variety everta (Popcorn) was carried out with an aim of establishing any karyotypic features of this plant which could be useful in designing crop improvement efforts for the crop. Fruits of the plant were obtained from operators and certified in a University Herbarium. Germinating root tips were pretreated in colchicine solution and fixed with acetic ethanol. Metaphase chromosomes were accessed after hydrolysis and squashing in orcein. A diploid chromosome count of 2N = 20 was recorded for all cells. The karyotype was highly asymmetrical with intrachromosomal asymmetry index of 0.4548 and interchromosomal asymmetry index of 0.4314. The shortarm had a very high coefficient of variation value of 84.14%, while total length coefficient of variation value was 43.14%. The implication of a history of both major and cryptic activities in this karyotype can be interpreted as karyotypic instability which could be exploited in improvement regimes such as recurrent selection.