HIGH DENSITY PROTECTED CULTURE OF PEACHES: A THREE YEAR RESEARCH STUDY ON "PERMANENT CANOPY" CULTIVATION IN SARDINIA

The experiment was carried out at the C.R.A.S. farm at Uta, in the country around Cagliari (39° 17' latitude North, 10 m. above sea level). It started in 1986 with the plantation of GF677 rootstocks which had been grafted in September the same year while the buds were dormant.

Three peach cultivars ("Maravilha", "San Pedro" and "Maycrest") and two nectarine cultivars ("Armking" and "Fla 3–4") were chosen for the experiment because of their mild low and medium temperature requirements.

A high plantation density was adopted with 6,660 trees per hectare with a distance between trees of 1.00 x 1.50 m.. The trees were cultivated on "permanent canopy" for the three year period 1990–1992.

Half the plantation was covered by two greenhouses in order to study the effect of greenhouse as against open field culture.

The results of the high density greenhouse cultivation of peaches are very encouraging both a far as regards yield and quality. "Maravilha" and "San Pedro" have given the most interesting results with mean values of 5.5 kg/tree and 4.5 kg/tree respectively.

The effect of "forcing" on time to maturity has been extremely interesting with a significative decrease in favour of the greenhouse cultivated trees as confronted to those grown in the open field. Average time to maturity was reduced by 24–28 days in common peaches and 17–21 days in nectarines.