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• Influence of various mineral supply on sweet corn root development

  49-52.

  F. Orosz

  I. Terbe

  Views:

  141

  Investigations into root strength have assumed particular importance with the emergence of American rootworm (Diabrotica virgifera-virgifera) as the number one pest, mainly as a result of monocultural production. Three treatments were applied in the trial: zero control treatment, treatment "A" (g/m2): 4, 47 N + 7, 89 P205 + 19, 74 K20 and treatment "B"(g/m²): 8, 94 N + 15, 78 P₂0₅ + 19, 74 K20. Measurements were made to find out whether the treatments had produced any significant difference between the root strength of the two varieties (normal sweet Puma F I and super sweet Dessert R75 Fl) at the two dates of measurement (tasseling, milk stage) in the year 2003. The treatments with a high phosphorous ratio resulted in an apparent increase in root strength with both varieties. There was a detectable difference in root strength also between the two points of measurement, suggesting that root development had remained stable. The treatments produced significant increase not only in the root strength but also in the yields of both varieties.

• Vegetative and micropropagation potential of Piper guineense (Schumach and Thonn)

  29-36

  A. M. SAKPERE

  V. N. Ezenu

  Views:

  187

  The continuous loss of forest plants due to deforestation, and the increasing demand for Piper guineense because of its medicinal and food value, has put a permanent pressure on its population in the wild where it is collected. A method for conservation and mass propagation is therefore required. This research was undertaken to determine the optimal concentration of auxin needed for vegetative propagation and to investigate the potential of Piper guineense for micropropagation. The auxin optimization study of vegetative propagation was based on the use of two-nodal stem cuttings treated with five different concentrations of indole-butyric acid (IBA). Growth parameters such as the number of sprouted, rooted and survived cuttings among others were determined. To investigate the potential of Piper guineense for micropropagation, nodal explants were subjected to different sterilizing treatments using ethanol, NaOCl, mancozeb, streptomycin and Plant Preservative Mixture (PPM). The effect of plant growth regulators (PGRs) was tested on sterilized nodal explants using full strength Murashige and Skoog (MS) hormone-free media alone as control and MS media supplemented with PGRs (BA, NAA and KIN) at different concentrations and combinations. Significant differences were observed across the treatments for all growth parameters measured. However, 2000 ppm IBA significantly (p<0.05) influenced sprouting and rooting of the stem cuttings. Piper guineense explants have deep tissue contaminants, which cannot be eradicated by surface sterilization alone except double sterilization using PPM. On control media, neither shoot nor root response was observed while the highest percentage of induced roots was obtained from explants cultured on MS +1 mg/L BA + 0.25 mg/L NAA. Shoot induction was only achieved when BA was used alone and when subcultured on media supplemented with NAA, which generated roots.