Relationship between leaf color index and berry set, fruit quality and yield on the 'Muscat of Alexandria' grape grown under a soilless culture
2009
Tamura, F., Okayama-ken. General Agriculture Center, Akaiwa (Japan). Agricultural Experiment Station | Fujii, Y.
The respective relationships between leaf color index (SPAD index measured using a chlorophyll meter, SPAD-502) and berry set, fruit quality, and yield were investigated for the 'Muscat of Alexandria' grape grown under a soilless culture. Significant correlation was observed between the berry set, berry size, and the SPAD index of the leaf attached on the fifth basal node for the periods from bud break to bloom. The number of berries per cluster and berry size increased concomitant with increased color index. Negative correlation was found between the SPAD index and sugar content. Results of this experiment, however, showed that the SPAD index was 30-45 at bloom, when sugar content of fruits indicated 15.9-18.8%. The sugar content was sufficient and the commercial values of the crop were not damaged markedly. These results suggest that the nutrient status is comparatively favorable in vine that the SPAD index of the fifth leaf be 40-44 at bloom from the perspective of fruit production.
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