Fruit and spur leaf growth and quality as influenced by low irradiance levels in pear

• Published in: Scientia horticulturae 1998-10, Vol.77 (3), p.195-205
• Main Authors: Garriz, P.I, Colavita, G.M, Alvarez, H.L
• Format: Article
• Language: English
• Subjects: Abscission; Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; Crop climate. Energy and radiation balances; Economic plant physiology; Fructification, ripening. Postharvest physiology; Fruit quality; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Growth; Growth and development; Leaf area; Pyrus communis L; Shading
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/S0304-4238(98)00182-4

The effects of shading on spur leaf and fruit growth and quality of Pyrus communis L. cv. `Bartlett' were evaluated in the High Valley region of Argentina. The trees were trained to palmette leader and fruit load was low. Treatments were application of shade using a 80% saran shade cloth, applied at two stages of fruit development: 2 October–3 December 1996 (14 days after full bloom (DAFB) to 76 DAFB, Stage I) and 3 December 1996–23 January 1997 (76–128 DAFB, Stage II). Meteorological data were continuously monitored. Shading during Stage I decreased area per spur leaf, specific leaf mass and fruit diameter by 16.70%, 20.88% and 10.80%, respectively, at 76 DAFB. There was no significant treatment effect on final fruit size, although shaded fruits tended to be smaller. Microscopic examinations showed contrasting anatomical features in leaves that were exposed to different light regimes. Induction of early fruit drop by cloth-covering individual branches during Stage I was also demonstrated here. Shading during Stage II yielded significantly ( P≤0.05) smaller fruits as compared to control and light reduction did not affect fruit firmness and soluble solids concentration. It was concluded that early shading reduced spur vigor and fruit load, whereas late shading diminished fruit size. These results suggest some goals of pruning and training for optimizing yield, by efficiently converting captured sunlight into fruit.