NEW VALUABLE ROOTSTOCKS FOR AN INTENSIVE CULTIVATION OF THE PLUM TREE
In the process of producing the plum-tree there are however, some difficulties whose solution would greatly increase the efficiency of this culture.
Thus referring only to the production of the grafted planting material the main problems to be solved aim at obtaining new rootstocks with an increased degree of affinity to the main sorts in the world assortment and a moderate growth for the creation of plantations of an intensive and superintensive character, shortening the period of obtaining the planting material and obtaining increased of grafted trees per ha.
With a view to solving these targets our staff has attempted to make their contribution by enriching the present range for grafting the plum-tree with new rootstocks.
The research has been carried on in 2 of the main natural areas where plum trees are cultivated in our country: Vîlcea and Horezu. The main pedoclimatic characteristics of this zone are: a rough relief with altitudes of 250–650 m, a soil having a high content of clay and the volume of annual precipitations of 715.7 mm. The mean annual temperature is of 10.2°C with temperatures falling to -27°C in January and frost of -2 to -3°C in April and October.
In this natural zone, in the course of time there have been formed dozens of autochthonous sorts of plum-trees which produce at present thus meeting the needs for fresh fruit or derived product.
Between 1972–1976 our staff has made in this zone a pomological study on the local sorts of plum-tree keeping for further research 15 of those considered more valuable in point of productivity adaptation to pedoclimatic conditions, resistence to the main diseases and pests characteristic of the plum-tree.
Thus the following sorts have been kept: Otesani 8, De Copaceni, Calugaresti, Pepenii, Gogosele, Molive, Troianu 9, Otesani 11, and some types of Mirobolan.
Otesani 8 presents a moderate growth, a reduced habitus, blossoms late in the year, is self-fertilizing, productive and shows a good resistence to frost, diseases and pests. Its fruit is small with a mediocre taste.
De Copaceni is a sort of medium vigour, with late blossoms, self-fertilizing, productive with a good resistence to frost, diseases and pests. Its fruit is large, finely coloured, non-adherent to stones, is good for consumption both fresh and dehydrated.
Calugaresti is a vigorous sort with a medium period of blossom, self-fertilizing with large and constant yellow large fruit, with