- S A Oosthuyse
- HortResearch SA, PO Box 3849, Tzaneen 0850, South Africa
- 2004
The main scaffold branches of bearing HLH Mauritius (Tai So) litchi trees were either girdled (cinctured) or left. To girdled or non-girdled trees, low-biuret urea, potassium nitrate, or amino acid complex were sprayed in mid-June 2003, prior to flowering in July. Furthermore, paclobutrazol was applied to the soil under the canopy in mid-March, 2003, the roots were pruned in early June, 2003, or the terminal branches were headed back by 30 to 45 cm in mid-June, 2003. The winter conditions (temperatures) were strongly inductive, this presumably masking any treatment benefit of stimulating bud-development and increasing flowering intensity. Winter pruning or girdling delayed buddevelopment,
reduced flowering intensity, and increased flowering stage variance. These effects were pronounced following winter pruning. Girdling markedly increased the number of fruits set per inflorescence and tree yield. Headed branched terminated by more leaves showed a greater propensity to initiate inflorescences as opposed to a new shoots. Flowering was more intense, set per inflorescence better, and the initiation of bud-development earlier on the sun-exposed as opposed to the more shaded side of the trees, this indicating the importance of canopy sun-exposure for increased tree performance. Potassium nitrate spraying increased inflorescence stage of development variance. Soil paclobutrazol application was ineffective in influencing inflorescence development stage or variance, or flowering intensity or fruit set. An effect in this regard would be expected when environmental conditions are less effective in inducing flowering. Repeating the study when winter conditions are less inductive was deemed necessary.