Resumo

LOPEZ M, Miguel Ángel; CHAVES, Bernardo; FLOREZ R, Víctor Julio  e  SALAZAR, Melba Ruth. Node appearance model for substrate grown carnation (Dianthus caryophyllus L.) cv. Delphi. Agron. colomb. [online]. 2010, vol.28, n.1, pp.47-54. ISSN 0120-9965.

Phenological models are designed to understand and predict plant development. The aim of this study was to determine the base temperature (Tb) for node appearance, and according to this relationship, to generate a phenological model for the first production peak of standard carnation cv. Delphi. The trial was established in the SENA facilities of the municipality of Mosquera (Cundinamarca, Colombia). There, under greenhouse conditions, carnation cuttings were planted in three different substrates (100% burnt rice husks; mixture of 65% burnt rice husks and 35% coconut fiber; mixture of 35% burnt rice husks and 65% coconut fiber). Tb was estimated by adjusting the exponential model for node appearance rate and accumulated temperature. Euler`s method was used for node simulation, and plant phenological development was determined through thermal time. The type of substrate did not influence node appearance average rate (0.102 nodes/day). Estimated Tb was 0.12°C, whereas 1,363.2 degree day (dd) accumulated from the pinch to flower bud appearance, and the harvest peak was reached at 2,226.5 dd. Node appearance proceeded rapidly in the earlier development stages, to gradually decline after flower  bud appearance. While the maximum number of observed nodes was 16.18, the model estimated the same parameter in 16.89. The model fits adequately the observed data, and shows a low square root of mean square error index (RSME = 0.28).

Palavras-chave : development; base temperature; thermal time; simulation.

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