Articles by Author: Petrus J Robbertse

Search results for Petrus J Robbertse

We found 30 results for you
  1. Plant anatomy as a tool for evaluating the effect of different levels of nitrogen, plant population density, row spacing and irrigation on kenaf (<em>Hibiscus cannabinus</em>) fibre development

    Plant anatomy as a tool for evaluating the effect of different levels of nitrogen, plant population density, row spacing and irrigation on kenaf (<em>Hibiscus cannabinus</em>) fibre development

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Kenaf (Hibiscus cannabinus) provides high-quality fibre that is used in papermaking, building materials and absorbents. The study aims were to conduct a proper anatomical study of fibre development in kenaf stems, and to investigate if the number of fibre wedges,...
  2. The Role of Genotype-Environment Interaction in Adaptability

    Item type: Journal Article • Journal: South African Forestry Journal
    The over sites ratio of clonal (familial) genotype-environment interaction (GEI) variance to mean trial variance determines the regression that is used to predict adaptability. Genotypic and environmental variances do not contribute significantly to this regression. Genotype x environment interaction effects...
  3. A preliminary study of the pollen of <em>Mangifera indica</em> L. cv. Haden in South Africa

    A preliminary study of the pollen of <em>Mangifera indica</em> L. cv. Haden in South Africa

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The effect of temperature and light intensity on the dehiscence of anthers of Mangifera indica L. cv. Haden and on the in vitro germination, stainability and viability of mango pollen grains was studied. Pollen of two mango cultivars grown in...
  4. The influence of temperature and boron on pollen germination in <em>Mangifera indica</em> L.

    The influence of temperature and boron on pollen germination in <em>Mangifera indica</em> L.

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Fruit set in the mango (Mangifera indica L.) cultivar ‘Haden’ is exceptionally low. In an effort to determine the reason for this phenomenon, the influences of temperature and application of boron on pollen germination and the effectiveness of cross- versus...
  5. Leaf characters of various tea clones in relation to quality

    Leaf characters of various tea clones in relation to quality

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The leaves of ten different tea clones were investigated to explore the possibility that structural differences exist between clones and that morphological characters relate to the quality of the infusion. Our results revealed a significant negative correlation between TF-values and...
  6. Preliminary investigation on the potential of <em>Clivia miniata</em> Regel as a cut flower

    Preliminary investigation on the potential of <em>Clivia miniata</em> Regel as a cut flower

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Clivia miniata Regel is widely cultivated as a garden ornamental and a pot plant. It occurs in many attractive shades of orange, red, yellow and pink but little information exists regarding its use as a cut flower. The possibility of...
  7. Effect of temperature on the growth of <em>Lachenalia</em> cv. Ronina during the bulb preparation phase

    Effect of temperature on the growth of <em>Lachenalia</em> cv. Ronina during the bulb preparation phase

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Lachenalia cultivars have excellent characteristics as flowering pot plants. The effect of three temperature regimes on the growth of small bulbs of Lachenalia cv. Ronina to flowering size (± 7 g) was studied. Potted bulbs were grown in three temperature...
  8. Low temperature treatment advances flowering in <em>Clivia miniata</em> (Lindley) Regel

    Low temperature treatment advances flowering in <em>Clivia miniata</em> (Lindley) Regel

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Clivia miniata plants were exposed to a cold treatment of 7.5–10 °C for 14 days in the dark from 24 April 2000. Compared to the non-cold treated control plants, the cold-treated plants started flowering four weeks earlier resulting in 80%...
  9. Effect of leaf-section position and physiological stage of the donor plant on <em>Lachenalia</em> leaf-cutting performance

    Effect of leaf-section position and physiological stage of the donor plant on <em>Lachenalia</em> leaf-cutting performance

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The effect of leaf-section position and physiological stage of the donor plant on leaf cutting performance was determined on three Lachenalia cultivars, viz ‘Romelia’, ‘Rupert’ and ‘Robyn’. Performance was evaluated in terms of leaf cutting survival, number of bulblets formed,...