Determinación de la fecha óptima de siembra en alcaucil

In Argentina artichoke seed multiplication has not been adopted to a great extent by horticulturists, hence this specie is mainly grown by vegetative propagated means. The objective of the present work was to evaluate different sowing dates on seed-grown artichoke production. The experience was conducted during 2003/05 at the Agronomy Faculty, Rosario National University, located at 33o 1′ S y 60o 59′ O. Imperial Star and Violeto Invernale cultivars were used as plant material along a completed randomized design with four replications. Ten different sowing dates were considered from March to December of 2003 and 2004. The number of artichokes, mean weight of the heads, yield, days to first harvest and harvest period were studied by analysis of variance. Waller-Duncan test was performed for mean comparisons. Highly significant differences were found among sowing dates for all evaluated traits. November sowing showed the highest yield (23.6 t·ha-1), due to an increased number (125.4·103) of heavier heads (179 g), and a longer harvest period as well. The most precocious harvest was attained after June sowing. However it presented the lowest yield (3.4 t·ha-1), number of artichokes (29.2·103) and head mean weight (117.6 g), as well as the shortest harvest period. In order to obtain maximum production of both cultivars from sexual propagation, the November sowing date is recommendable because its production coincides with a time of competitive prices generating a grater gross income.---------------------------------------------------------------------------------------El alcaucil se propaga en forma asexual siendo en Argentina la utilización de semillas una práctica poco difundida. A fin de establecer la fecha óptima de siembra en cultivares de multiplicación sexual, se realizó el presente trabajo en la Facultad de Ciencias Agrarias de la Universidad Nacional de Rosario ubicada a 33o 1′ S y 60o 59′ O entre 2003 y 2005. Como material experimental se utilizó Imperial Star (IS) y Violeto Invernale (VI), efectuándose siembras mensuales en un dise o de bloques completamente aleatorizado desde marzo a diciembre de 2003 y 2004. Número de capítulos (NC), peso medio (PM), rendimiento (RE), días a cosecha (DAC) y días de cosecha (DDC) fueron estudiadas a través de análisis de varianza y la prueba de Waller- Duncan para la comparación de medias. Al analizar las fechas de siembra en ambas cultivares se encontraron diferencias altamente significativas en todas las variables. La siembra de noviembre produjo mayor NC (125,4·103), PM (179 g), RE (23,6t·ha-1) y DDC sin demos