ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Long-term effect of growth retardants and pruning on growth, yield and fruit quality of litchi (Litchi chinensis Sonn.) trees.

Oosthuizen, J. H.; Froneman, I. J.; Roe, D. J.;

Journal of the Southern African Society for Horticultural Sciences Year: 1995 Vol: 5 Issue: 2 Pages: 61-63 Ref: 11 ref.

1995

บทคัดย่อ

Litchi cv. Mauritius trees, commonly grown in South Africa, are vigorous and fast growing and overcrowding occurs within 8-10 years of establishment. High density plantings are therefore not possible unless trees are removed when they are at their most productive. Methods to control the size of adult trees were investigated over a 5-year period at Friedenheim (25 deg S.), a warm subtropical area of South Africa. Treatments consisted of pruning fruit-bearing branches back by 300 mm at harvest, applying foliar sprays of paclobutrazol (PP) onto the postharvest flush and/or young flower panicles, soil drenching with PP, a combination of pruning and soil applications of PP, and chlormequat-chloride foliar sprays onto the postharvest flush and young flower panicles. Annual yields were recorded. Residues of PP in fruit arils were determined. Height and canopy diameter of trees in the different treatments were measured before and after the trial. Effective control of tree size was achieved by pruning, s

oil application of PP and a combination of these 2 methods. However, treatments involving soil PP application reduced cumulative yields over 5 seasons compared with controls; PP residues of 0.06-0.09 mg/kg were found in fruits. Chlormequat-chloride treatments reduced yields in the first couple of years and were then discontinued due to unavailability. Pruning of bearing branches was recommended as a method of controlling tree size because it did not affect long-term yields and was also environmentally friendly.