DIFFERENT PLANT DENSITIES OF MICROPROPAGATED 'SPINOSO SARDO' ARTICHOKES

A large quantity of vegetable material used in Sardinia for ‘Spinoso Sardo’ artichoke multiplication comes from original nuclei of mother plants, originated by selection and micropropagation of different clones, in order to regain vigour and productivity. In this work productivity and vegetative behaviour of plants belonging to clone “M”, obtained in vitro, was evaluated. The trial was carried out with four different plant density: 7000, 8500, 10000 and 11500 plants/ha. First two thesis represented standard conditions adopted by farmers in different areas, while the other two plant density were planned to increase productivity. The trial was carried out in an important artichoke growing area located in the western coast of Sardinia (Oristano, Italy) and repeated in two cycles. Each plot was set up in 2005 and 2006 using young plants obtained through pre-germinated “ovoli”. Experimental design adopted was a four replication randomized block. Each plot included 48 plants, sized 1.40 m between rows and respectively 1, 0.8, 0.7 and 0.6 m on the row. The higher plant density showed more artichoke heads per surface unit; however a relevant part of these products was classified as 2nd commercial category or even as unmarketable. Higher density also had negative effects on earliness and uniformity of artichoke heads. In conclusion, according to obtained experimental data, artichoke growing with plant density higher than 8500 plants/ha shows no economic convenience.