บทคัดย่องานวิจัย

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The long-term effect of growth regulators and pruning on the size, yield and fruit quality of litchi trees.

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

Yearbook - South African Litchi Growers' Association Year: 1995 Vol: 7 Pages: 5-10 Ref: 21 ref.

1995

บทคัดย่อ

The long-term effect of growth regulators and pruning on the size, yield and fruit quality of litchi trees.

 

Trials were conducted over 5 years with mature trees of cv. HLH Mauritius at Friedenheim Experimental Farm (25 deg S., 671 m a.s.l.). The following treatments were compared: pruning fruit-bearing branches by 30 cm at harvest; applying foliar sprays of paclobutrazol (PP333) at various rates onto postharvest flush growth or young flower panicles; drenching soil with PP333 at various rates; combining pruning and soil applications of PP333; or applying foliar sprays of chlormequat-chloride (CCC) at various rates onto postharvest flush growth and also young flower panicles. Data are tabulated on annual yields, fruit quality, residues of PP333 in fruits, and tree height and canopy diameter at different stages of the experiment. Effective tree size control and manipulation were achieved by pruning and/or soil application of PP333. However, to be justified economically these treatments require more intensive and higher inputs. Increased yields were not always achieved and a wider variation in yield occu

rred in comparison with untreated control trees. PP333 was ineffective when applied as a foliar spray. Soil treatment resulted in traces of residues in the aril of the fruit, the lowest limit of detection being 0.04 p.p.m. For this reason, PP333 cannot be recommended for soil treatment commercially, particularly if the crop is to be exported. CCC gave unsatisfactory results in this trial and adversely affected yields.